Guest

Cisco IOS Software Releases 12.2 T

SIP Support for Media Forking

Table Of Contents

SIP Support for Media Forking

Contents

Prerequisites for SIP Support for Media Forking

Restrictions for SIP Support for Media Forking

Information About SIP Support for Media Forking

Benefits of SIP Support for Media Forking

Overview of Media Streams

Voice Media Streams

DTMF-Relay Media Streams

Voice Plus DTMF-Relay Media Streams

Multiple Codec Selection Order and Dynamic Payload Codecs

Media Forking Applications

Media Forking Initiation

How to Configure SIP Support for Media Forking

Configuring Codec Complexity on Cisco 2600 Series Routers, Cisco 3600 Series Routers, Cisco 37xx Routers, and Cisco AS5300 Routers

Configuring Codec Complexity on Cisco 7200 Series Routers

Mapping Payload Types to Dynamic Payload Codecs

Configuring Multiple Codec Selection Order

Monitoring SIP Support for Media Forking

Verifying Codec Complexity Settings

Verifying Network Dial Peers

Verifying Media Forking on SIP Calls

Troubleshooting SIP Support for Media Forking

Configuration Examples for SIP Support for Media Forking

SIP Network Using Media Forking Example

Edge Gateway Configuration Example

Party A Configuration Example

Party B Configuration Example

Party C Configuration Example

Party A Initial Call Setup Trace Example

Party B Initial Call Setup Trace Example

Party A Add Second Stream Trace Example

Party C Add Second Stream Trace Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

debug ccsip events

debug ccsip info

debug ccsip media

show sip-ua calls

Glossary


SIP Support for Media Forking


The SIP Support for Media Forking feature provides the ability to create midcall multiple streams (or branches) of audio associated with a single call and then send those streams of data to different destinations. The SIP Support for Media Forking feature allows service providers to use technologies such as speech recognition, voice authentication, and text-to-speech conversion to provide sophisticated services to their end-user customers. An example is a web-browsing application that uses voice recognition and text-to-speech (TTS) technology to make reservations, verify shipments, or order products.

Feature Specifications for SIP Support for Media Forking

Feature History
 
Release
Modification

12.2(15)T

This feature was introduced.

Supported Platforms

Cisco 2620XM, Cisco 2621XM, Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3620, Cisco 3631, Cisco 3640, Cisco 3660, Cisco 3725, Cisco 3745, Cisco 7200 series, and Cisco AS5300.


Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

Prerequisites for SIP Support for Media Forking

Restrictions for SIP Support for Media Forking

Information About SIP Support for Media Forking

How to Configure SIP Support for Media Forking

Configuration Examples for SIP Support for Media Forking

Additional References

Command Reference

Glossary

Prerequisites for SIP Support for Media Forking

The following are general prerequisites for Session Initiation Protocol (SIP) deployment:

Ensure that your Cisco router has the minimum memory requirements necessary for voice capabilities.

Establish a working IP network.

For more information about configuring IP, refer to the following document:

Cisco IOS IP Configuration GuideRelease 12.2

Configure VoIP.

For more information about configuring VoIP, refer to the following document:

Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2

The following are specific prerequisites for the SIP Support for Media Forking feature:

Configure the gateway receive-rtcp timer (using the timer receive-rtcp command on the gateway) if a SIP media inactivity timer is desired. The timer monitors and disconnects calls if no Real-Time Control Protocol (RTCP) packets are received within a configurable time period. If you are using Cisco IOS Release 12.2(11)T or higher, refer to the Configuring SIP Connection-Oriented Media, Forking, and MLPP Features chapter of the Cisco IOS SIP Configuration Guide specific to your release.

If using a Cisco 2600 series router, Cisco 3600 series router, or a Cisco 37xx router, ensure that the voice card is configured for high-complexity mode of operation for full media-forking functionality.

If using a Cisco 7200 series router, ensure that the voice card is configured for high-complexity mode of operation.

If using a Cisco AS5300 universal access server, ensure that the proper version of VCWare is loaded onto your router. For media forking, the voice feature card used is the DSPM Voice (C542 or C549).

Restrictions for SIP Support for Media Forking

Unsupported Features in the SIP Support for Media Forking Feature

The ability to use IP multicast.

The ability to create streams with different codecs.

The ability to use media forking functionality over Transmission Control Protocol (TCP). User Datagram Protocol (UDP) only is supported.

The ability to make fax calls when multiple streams are used.

The ability to make modem calls when multiple streams ar e used.

IP-to-IP hairpinning, because there is no telephony call leg to be associated with a call.

When using no voice activity detection (VAD), you can use 10 percent of the capacity of the router to make media forked calls. If no VAD is configured on the Cisco 7200 series, a maximum of 15 channels can be used. For example, on a Cisco 2691, two T1s are supported. Ten percent of two T1s is 4.8 calls, so 4.8 media forking calls can be performed when no VAD is configured. For a Cisco AS5300, four T1s are supported that give a total of 96 calls. Ten percent of 96 is 9.6 calls, so 9.6 media forking calls can be performed when no VAD is configured.

Restrictions on Codec Usage

The codecs implemented are G.711, G.729, and G.726 on all supported platforms. No other codecs are supported.

For dynamic payload type codecs (G.726), the payload type must be the same for all streams in the call. This ensures that the codec is mapped to the same payload type on all streams of a re-Invite message. See the "Mapping Payload Types to Dynamic Payload Codecs" section for more information.

The codecs on all the streams must be the same and must be one of the supported codecs. If a re-Invite message is received and multiple codecs are listed in the m-lines of the forked-media streams, the gateway attempts to find the codec in the list that matches the first stream. If a matching codec is not found, the stream is rejected by setting the port number to 0 in the response. See the "Mapping Payload Types to Dynamic Payload Codecs" section for more information.

Restrictions on Forking Functionality and Voice Feature Cards

With the Cisco 2600 series routers, Cisco 3600 series routers, or Cisco 37xx routers, forking is partially supported for NM-HDV configured for medium- complexity mode of operation. A maximum of two streams is supported, and the only combinations supported are:

Voice only on both streams.

Voice plus dual-tone multifrequency (DTMF)-relay on both streams.

For full functionality, the NM-HDV should be configured for high-complexity mode of operation.

With the Cisco 7200 series routers, the Enhanced High-Capacity Digital Voice port adapter (PA-VXC-2TE1+ T1/E1) must be configured for high-complexity mode of operation.

With the Cisco AS5300 universal access server, DSPM Voice (C542 and C549) must be configured.

Restrictions on DTMF-Relay

DTMF-relay is supported as described in RFC 2833, RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals. Cisco proprietary DTMF is not supported.

When DTMF-relay is configured, only the Real-Time Transport Protocol Named Telephony Event (RTP-NTE) payload format can be used in a forked call. RTP-NTE is described in RFC 2833 and prevents the generation of spurious digits at the receiving gateway.

Streams that include only DTMF-relay packets can be used only in a two-stream call and must be established as the second stream.

All forked voice-only and voice plus DTMF-relay streams must use the same codec.

Restrictions on Media Streams

Multiple Domain Name System (DNS) media queries are not supported on all media streams. DNS query is done on the fully qualified domain name (FDQN) of the initial stream only.

Media streams are created and deleted only through re-Invite messages. They are not created through the command-line interface (CLI).

A maximum of three voice-over-IP media streams are supported because three streams can be concurrently sent to the digital signal processor (DSP).

Calls that have a single stream (that is, a conventional two-party call) cannot be set up as DTMF-only.

The first stream cannot be deleted while other streams are active, nor can it be put on hold.

The stream type of an active stream cannot be modified. For example, you cannot change a voice-only stream to voice plus DTMF only.

Information About SIP Support for Media Forking

To configure the SIP Support for Media Forking feature, it is helpful to understand the following concepts:

Benefits of SIP Support for Media Forking

Overview of Media Streams

Multiple Codec Selection Order and Dynamic Payload Codecs

Media Forking Applications

Media Forking Initiation

Benefits of SIP Support for Media Forking

The SIP Support for Media Forking feature allows service providers to deploy a core SIP network server and use technologies such as speech recognition, voice authentication, and text-to-speech conversion to provide sophisticated services to their end-user customers. Service providers use the multiple media streams provided by media forking to monitor the progress of customers through specific applications or requests, which in turn helps the customer transition easily from one facet of the application to another. One example is a web-browsing application that uses voice recognition and text-to-speech (TTS) technology to make reservations, verify shipments, or order products.

SIP media streams are created and deleted only through re-Invite messages; no CLI is required.

Overview of Media Streams

With the SIP Support for Media Forking feature you can create up to three Real-Time Transport Protocol (RTP) media streams to and from a single DS0 channel. In addition, separate gateway destinations (IP address or UDP port) are maintained for each of the streams. The streams are bidirectional; media received from the destination gateways are mixed in the DSP before being sent to the DS0 channel, and pulse code modulation (PCM) received from the DS0 is duplicated and sent to the destination gateways.

Originating gateways establish multiple media streams on the basis of Session Description Protocol (SDP) information included in midcall re-Invites received from a destination gateway, third-party call controller, or other SIP signaling entity. Only one SIP call leg is involved in media forking at the gateway, so the SIP signaling entity that initiates the re-Invites must be capable of aggregating the media information for multiple destinations (such as IP address, port number, payload types, or codecs) into one SDP description. Multiple m-lines in the SDP are used to indicate media forking, with each m-line representing one media destination.


Note SIP media streams are created and deleted only through re-Invite messages; no specific CLI is required.


The ability to create midcall multiple streams (or branches) of audio associated with a single call and send those streams of data to different destinations is similar to a three-way or conference call. A media-forked call has some differences. For example, in a three-way call, each party hears all of the other parties. But in a media-forked call, only the originating caller (the controller) hears the audio (voice and DTMF digits) from all the other participants. The other participants hear audio only from the originating caller and not from each other.

Another difference between a three-way call and a media-forked call is that media streams can be configured on the gateway. Three-way calls send the audio to all of the other parties involved in the call. However, media-forking permits each media stream to be independently configured. For example, one media stream to one party may include both voice and DTMF digits, whereas another media stream to another party may include only DTMF digits.

The SIP Support for Media Forking feature supports three types of media streams: voice, DTMF-relay only, and voice plus DTMF-relay.

Voice Media Streams

Voice-only media streams send all audio from the DS0 channel, and the audio is encoded according to the selected codec. Voice-only media streams have the following characteristics:

DTMF digits are sent as in-band audio.

All forked streams must use the same codec, which is referred to as simple forking.

Only the following codecs and their variants are allowed: G.711, G.726, and G.729.

For the G.726 codecs, dynamic payload types are negotiated in SDP. SDP messages contain capabilities information that is exchanged between gateways. The payload types must be the same for all streams in the call. See the "Mapping Payload Types to Dynamic Payload Codecs" section for more information.

DTMF-Relay Media Streams

DTMF-relay provides reliable digit relay between VoIP gateways and a standardized means of transporting DTMF tones in RTP packets. DTMF-relay media streams have the following characteristics:

DTMF-relay media streams do not include voice and do not use a codec. DTMF-relay packets are sent when the originating party presses a DTMF digit.

Only RTP-NTE can be used in a forked DTMF-relay call. RTP-NTE is used to transport DTMF digits and other telephony events between two endpoints. RTP-NTE prevents the generation of spurious digits at the receiving gateway and is further described in RFC 2833.

DTMF-relay streams are supported only on calls with two established streams and can appear only as the second stream.

The payload-type value assigned to DTMF-relay packets in SDP must be the same for all streams that use DTMF-relay. The default payload type for Cisco gateways is 101. For more information on payload types see the "Multiple Codec Selection Order and Dynamic Payload Codecs" section for more information.

Voice Plus DTMF-Relay Media Streams

Voice plus DTMF-relay media streams send both encoded voice and DTMF-relay packets and have the following characteristics:

The receiving gateway can distinguish the voice component from the DTMF component.

Unlike DTMF-relay, voice plus DTMF is supported on any of the established streams of a forked call.

Only RTP-NTE can be used in a forked DTMF-relay call.

All streams must use the same codec (simple forking).

Only the following codecs and their variants are allowed: G.711, G.726, and G.729.

For the G.726 codecs, dynamic payload types are negotiated in SDP. SDP messages contain capabilities information that are exchanged between gateways. The payload types must be the same for all streams in the call. See the "Mapping Payload Types to Dynamic Payload Codecs" section for more information.

The payload-type value assigned to DTMF-relay packets in SDP must be the same for all streams that use DTMF-relay. The default payload type for Cisco gateways is 101.

Multiple Codec Selection Order and Dynamic Payload Codecs

When using multiple codecs you must create a voice class in which you define a selection order for codecs, and you can then apply the voice class to VoIP dial peers. The voice class codec global configuration command allows you to define the voice class that contains the codec selection order. Then you use the voice-class codec dial-peer configuration command to apply the class to individual dial peers.

If there are any codecs that use dynamic payload types (g726r16, g726r24), Cisco IOS software assigns the payload types to these codecs in the order in which they appear in the configuration, starting with the first available payload type in the dynamic range. The range for dynamic payload types is from 96 to 127, but Cisco IOS software preassigns the following payload types by default:

Range
Function

96

fax

97

fax-ack

100

NSE

101

NTE

121

DTMF-relay

122

Fax-relay

123

CAS

125

ClearChan

Because the payload types have been reserved by the default assignments shown in the table, Cisco IOS software automatically assigns 98 to the first dynamic codec in the dial-peer configuration, 99 to the second, and 102 to the third.

Some of these preassigned payload types can be changed with the modem relay (dial-peer) command. The modem relay (dial-peer) command allows changes to the available payload types that can be used for codecs.

For outgoing calls on the originating gateway, all of the codecs that are configured in the codec list used by the dial peer are included in the SDP of the Invite message.

On the terminating gateway, Cisco IOS software always uses the dynamic payload types that the originating gateway specified in the SDP of the Invite message. This practice avoids the problem of misaligned payload types for most call types. The exception is when a delayed-media Invite message is received. A delayed-media Invite can be used by a voice portal to signal a terminating gateway before re-Inviting a forking gateway. If a delayed-media Invite is used, the Invite message does not contain SDP information, and the terminating gateway must advertise its own codecs and payload types. It does this in the SDP of its response message (either a 183 or a 200 OK). The terminating gateway assigns payload types to dynamic codecs using the same rules as the originating gateway. However, if there is a difference in either the preassigned dynamic payload types or the order in which the dynamic codecs are listed in the codec list used by the dial peer, the payload types may not be assigned consistently on the originating and terminating gateways. If the terminating gateway selects a different payload type for a dynamic codec, the call may fail.

If a G.726 codec is assigned in the first active stream of the call, there are some scenarios in which the voice portal sends a delayed-media re-Invite message to the second or third terminating gateway. Then, it is necessary to ensure that the originating gateway and the second and third terminating gateways have the same preassigned payload types and the same order of dynamic codecs in the codec list for the dial peer being used for the call. Otherwise, the added media stream may be rejected by the originating gateway if the payload types do not match.

To configure codec selection order, perform the tasks described in the following sections:

Creating a Voice Class to Define Codec Selection Order

Applying Codec Selection Order to a VoIP Dial Peer

Media Forking Applications

A web-browsing application that uses voice recognition and text-to-speech (TTS) technology to make reservations, verify shipments, or order products is a typical application of media forking. In Figure 1, a client (party A) uses a telephone to browse the web. Party A calls the voice portal (party B), and the call is routed through the originating gateway. The voice portal operates like a standard voice gateway and terminates calls to a voice response system that has voice recognition and TTS capabilities. This voice response system takes input from party A by DTMF digits or voice recognition and returns responses (for example, stock quotes retrieved from the web) to party A.

The voice portal, or party B, is also capable of third-party call control (3pcc) and can set up a call between party A and a third participant (party C) without requiring direct signaling between party A and party C. One example of a possible call between parties A and C is if party A found a restaurant listing while browsing the web and wanted to speak directly to the restaurant to make reservations.

Another feature of the voice portal is that once the call between parties A and C is established, the voice portal can continue to monitor the audio from party A. By doing so, the voice portal can terminate the connection between parties A and C when a preestablished DTMF digit or voice command is received. Party B retains the connection between itself and party A, in case party A has any further requests. Continuing with the restaurant example, the continuous connection is important if party A decides to query yet another restaurant. Party A simply goes back to the connection with party B, who sets up a call with the new restaurant.

Figure 1 Media Forking Application

Another important aspect of media forking is that although there can be more than one media destination, there is only one signaling destination (in this case, the voice portal). The call leg that was originally set up (from the originating gateway to the voice portal) is maintained for the life of the session. The media destinations are independent of the signaling destination, so media streams (or new destinations) can be added and removed dynamically through re-Invite messages. Media streams are created and deleted only through re-Invite messages rather than through any command-line interfaces (CLIs).

If you configure the timer receive-rtcp command for a gateway, a Session Initiation Protocol (SIP) media inactivity timer is started for each active media stream. The timer monitors and disconnects calls if no RTCP packets are received within a configurable time period. If any of the timers expire, the entire call is terminated—not just the stream on which the timer expired. If a stream is put on call hold, the timer for that stream is stopped. When the stream is taken off hold, the timer for that stream is started again.

There is a maximum of three VoIP media streams that can be established per call. Figure 2 shows the maximum number of streams.

Figure 2 Multiple Streams

Media Forking Initiation

Media forking is initiated by specifying multiple media fields (m-lines) in the SDP of a re-Invite message. The rules for adding and deleting multiple m-lines conform to RFC 2543, SIP: Session Initiation Protocol Appendix B.

Multiple streams are not created through command-line interfaces.

How to Configure SIP Support for Media Forking

See the following sections for configuration, monitoring, and troubleshooting tasks for this feature:

Configuring Codec Complexity on Cisco 2600 Series Routers, Cisco 3600 Series Routers, Cisco 37xx Routers, and Cisco AS5300 Routers (required)

Configuring Codec Complexity on Cisco 7200 Series Routers (required)

Mapping Payload Types to Dynamic Payload Codecs (required)

Monitoring SIP Support for Media Forking (optional)

Troubleshooting SIP Support for Media Forking (optional)

Configuring Codec Complexity on Cisco 2600 Series Routers, Cisco 3600 Series Routers, Cisco 37xx Routers, and Cisco AS5300 Routers

Configuring the correct codec complexity is required for media-forked calls. For the Cisco AS5300 access server, codec complexity is determined by the VCWare code that is loaded on the voice feature card (VFC). To download Cisco VCWare software, refer to the Cisco software download page.


Note This note applies to routers that have already been configured but need their codec complexity changed to high. If there is a DS0 group or PRI group assigned to any T1 controllers on the card, the DS0 or PRI groups must be removed. To remove the groups, shut down the voice ports associated with the groups. Then follow the procedure below.


SUMMARY STEPS

1. enable

2. configure terminal

3. voice card slot

4. codec complexity {high | medium} [ecan-extended]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

voice-card slot

Example:

Router(config)# voice-card 1

Enters voice-card configuration mode and configures a voice card. The slot argument specifies the voice-card slot location.

Step 4 

codec complexity {high | medium} [ecan-extended]

Example:

Router(config-voice-card)# codec complexity high

Specifies call density and codec complexity according to the codec standard that is being use.

For the Cisco 2691 and Cisco 26xxXM routers, set the codec complexity to high for full forking functionality. With high-complexity packaging, each DSP supports two voice channels.

For the Cisco 3600 series or the Cisco 37xx routers, set the codec complexity to high for full forking functionality.

Configuring Codec Complexity on Cisco 7200 Series Routers

On the Cisco 7200 series routers, codec complexity is configured on the DSP interface.

SUMMARY STEPS

1. enable

2. show interfaces dspfarm [slot/port] dsp [number] [long | short]

3. configure terminal

4. dspint dspfarm slot/port

5. codec high

6. description string

7. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show interface dspfarm [slot/port] dsp [number] [long | short]

Example:

Router# show interface dspfarm 3/0

Displays DSP voice channel activity. The keywords and arguments are defined as follows:

slot: Slot location of the port adapter.

port: Port number on the port adapter.

dsp: DSP information.

number: Number of DSP sets to display. Range is from 1 to 30.

long: Detailed DSP information.

short: Brief DSP information.

Use this command with the SIP Support for Media Forking feature to learn if any DSP voice channels are in the busy state. If voice channels are busy, codec complexity cannot be changed. All DSP channels must be in the idle state to make changes.

Step 3 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 4 

dspint dspfarm slot/port

Example:

Router(config)# dspint dspfarm 2/0

Enters DSP interface configuration mode. The slot/port argument specifies the slot and port numbers of the interface.

Step 5 

codec high

Example:

Router(config-dspfarm)# codec high

Specifies call density and codec complexity based on a particular codec standard.

Use the high keyword with the SIP Support for Media Forking feature. The high keyword supports two encoded voice channels. For this feature, the following codecs and their variants are supported: G.711, G.726, and G.729.

Step 6 

description string

Example:

Router(config-dspfarm)# description marketing_dept

Includes a specific description (string) about the DSP interface. This information is displayed in the output and does not affect the operation of the interface in any way.

Step 7 

exit

Example:

Router(config-dspfarm)# exit

Exits DSP interface configuration mode.

Mapping Payload Types to Dynamic Payload Codecs

The process used by Cisco IOS software to map payload types to dynamic payload codecs is important in media-forked calls because all media streams must use the same payload type.

VoIP dial peers can list codecs in two ways depending on whether a single codec or multiple codecs are to be assigned to the dial-peer. To configure a single codec in the dial-peer mode, perform the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. dial-peer voice tag voip

4. codec codec [bytes payload-size]

5. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

dial-peer voice tag voip

Example:

Router(config)# dial-peer voice 29 voip

Enters dial-peer configuration mode. The tag value is a tag that uniquely identifies the dial peer (this number has local significance only).

The following keyword can be used for configuring codecs:

voip—Indicates that this is a VoIP peer using voice encapsulation on the plain old telephone service (POTS) network.

Step 4 

codec codec [bytes payload-size]

Example:

Router(config-dial-peer)# codec g729r8

Specifies a codec for the dial peer. The following codec types can be used with media forking:

g711alaw
g711ulaw
g726r16
g726r24
g726r32
g729br8
g729r8

The default is g729r8.

The voice payload can also be specified in bytes of each frame.

Step 5 

exit

Example:

Router(config-dial-peer)# exit

Exits dial-peer configuration mode.

Configuring Multiple Codec Selection Order

With multiple codecs you can create a voice class in which you define a selection order for codecs, and you can then apply the voice class to VoIP dial peers. The voice class codec global configuration command allows you to define the voice class that contains the codec selection order. Then you use the voice-class codec dial-peer configuration command to apply the class to individual dial peers.

You can configure more than one voice class codec list for your network. The codec lists should be configured and applied to one or more dial peers based on what codecs (and the order) you want supported for the dial peers. You need to define selection order if you want more than one codec supported for a given dial peer.

To configure codec selection order, perform the tasks described in the following sections:

Creating a Voice Class to Define Codec Selection Order

Applying Codec Selection Order to a VoIP Dial Peer

Creating a Voice Class to Define Codec Selection Order

The order of preference for selecting a codec when the router negotiates with a destination router must be set.

SUMMARY STEPS

1. enable

2. configure terminal

3. voice class codec tag

4. codec preference value codec-type [bytes payload-size]

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

voice class codec tag

Example:

Router(config)# voice class codec 99

Enters voice-class configuration mode and assigns an identification tag number for a codec voice class. The range for the tag argument is from 1 to 10000, and the value of the tag argument must be unique on the router.

Step 4 

codec preference value codec-type [bytes payload-size]

Example:

Router(config-voice-class)# codec preference 1 g711alaw

Specifies a list of preferred codecs to use on a dial peer. Repeat this command to specify the preferred selection order for additional codecs, if required.

Applying Codec Selection Order to a VoIP Dial Peer

To apply voice-class codec attributes to a VoIP dial peer, perform the following steps:

SUMMARY STEPS

1. enable

2. configure terminal

3. dial-peer voice tag voip

4. voice-class codec tag

5. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

dial-peer voice tag voip

Example:

Router(config)# dial-peer voice 16 voip

Defines a VoIP dial peer and enters dial-peer configuration mode.

The tag argument value is a number that identifies the dial peer and must be unique on the router.

Step 4 

voice-class codec tag

Example:

Router(config-dial-peer)# voice-class codec 99

Assigns a previously configured codec selection preference list (codec voice class) to a VoIP dial peer. The configured codec selection is the voice class that you created in "Creating a Voice Class to Define Codec Selection Order" section.The value of the tag argument maps to the tag number created using the voice class codec global configuration command.

The voice-class command in dial-peer configuration mode is entered with a hyphen. The voice class command in global configuration mode is entered without the hyphen.

Step 5 

exit

Example:

Router(config-dial-peer)# exit

Exits dial-peer configuration mode.


Note The procedures above create a voice class. For the complete dial-peer configuration procedure, refer to the Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2.


Monitoring SIP Support for Media Forking

To monitor codec selection order, perform the tasks described in the following sections:

Verifying Codec Complexity Settings

Verifying Network Dial Peers

Verifying Media Forking on SIP Calls

Verifying Codec Complexity Settings

On a Cisco 2600 series router, Cisco 3600 series router, Cisco 37xx router, or a Cisco 7200 series router, the codec complexity can be verified by entering the show running-config command, which displays the current voice-card setting. If medium-complexity is specified, the codec complexity setting is not displayed. If high-complexity is specified, the setting codec complexity high is displayed. The following example shows an excerpt from the command output if high-complexity has been specified:

Building configuration...

Current configuration : 1864 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log uptime
no service password-encryption
!
!
memory-size iomem 10
voice-card 1
 codec complexity high
!
ip subnet-zero

Note For the Cisco AS5300 access server, codec complexity is dependant on what VCWare image is loaded on the voice feature card (VFC).


The following example shows an excerpt from the show voice dsp command, which displays the current status of all DSP voice channels, including codecs:

Router# show voice dsp

DSP#0: state IN SERVICE, 2 channels allocated
channel#0: voice port 1/0, codec G711 ulaw, state UP
channel#1: voice port 1/1, codec G711 ulaw, state UP
DSP#1: state IN SERVICE, 2 channels allocated
channel#0: voice port 2/0, codec G711 ulaw, state UP
channel#1: voice port 2/1, codec G711 ulaw, state UP
DSP#2: state RESET, 0 channels allocated

Verifying Network Dial Peers

Follow the procedure below to verify dial-peer configuration. To learn more about these commands, refer to the Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2, or the Cisco IOS Voice, Video, and Fax Command Reference, Release 12.2.

To verify the network dial peers, enter the following command in privileged EXEC mode:

Router# show dial-peer voice sum 

dial-peer hunt 0 
AD PRE PASS 
TAG TYPE MIN OPER PREFIX DEST-PATTERN FER THRU SESS-TARGET PORT 
110 voip up up    555110. 0 syst ipv4:172.18.195.49 
210 voip up up    555330. 0 syst ipv4:172.18.195.49 
200 pots up up    5553300 0 2/0/1 
101 pots up up    5551100 0 2/0/0 
366 voip up up    366.... 0 syst ipv4:172.18.195.49 

Verifying Media Forking on SIP Calls

The following example shows the show sip-ua calls command. This command is used to display the user agent client (UAC) and user agent server (UAS) information on SIP calls. It includes information about each media stream, up to three media streams if it is a media-forked call. It is useful in debugging, because it shows if an active call is forked.

To verify the UAC and UAS information on SIP calls, enter the following command in privileged EXEC mode:

Router# show sip-ua calls

SIP UAC CALL INFO

Call 1 
SIP Call ID : 515205D4-20B711D6-8015FF77-1973C402@172.18.195.49 
 State of the call : STATE_ACTIVE (6) 
 Substate of the call : SUBSTATE_NONE (0) 
 Calling Number : 555 0200 
 Called Number : 5551101 
 Bit Flags : 0x12120030 0x220000 
 Source IP Address (Sig ): 172.18.195.49 
 Destn SIP Req Addr:Port : 172.18.207.18:5063 
 Destn SIP Resp Addr:Port: 172.18.207.18:5063 
 Destination Name : 172.18.207.18 
 Number of Media Streams : 4 
 Number of Active Streams: 3 
 RTP Fork Object : 0x637C7B60 
 Media Stream 1 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 28 
  Stream Type : voice-only (0) 
  Negotiated Codec : g711ulaw (160 bytes) 
  Codec Payload Type : 0 
  Negotiated Dtmf-relay : inband-voice 
  Dtmf-relay Payload Type : 0 
  Media Source IP Addr:Port: 172.18.195.49:19444 
  Media Dest IP Addr:Port : 172.18.193.190:16890 
 Media Stream 2 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 33 
  Stream Type : voice+dtmf (1) 
  Negotiated Codec : g711ulaw (160 bytes) 
  Codec Payload Type : 0 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:18928 
  Media Dest IP Addr:Port : 172.18.195.73:18246 
 Media Stream 3 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 34 
  Stream Type : dtmf-only (2) 
  Negotiated Codec : No Codec (0 bytes) 
  Codec Payload Type : -1 (None) 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:18428 
  Media Dest IP Addr:Port : 172.16.123.99:34463 
 Media Stream 4 
  State of the stream : STREAM_DEAD 
  Stream Call ID : -1 
  Stream Type : dtmf-only (2) 
  Negotiated Codec : No Codec (0 bytes) 
  Codec Payload Type : -1 (None) 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:0 
  Media Dest IP Addr:Port : 172.16.123.99:0

 Number of UAC calls: 1

SIP UAS CALL INFO

 Number of UAS calls: 0

Troubleshooting SIP Support for Media Forking

To troubleshoot the SIP Support for Media Forking feature, perform the following steps:

Make sure that you can make a voice call.

If you are using codec types g726r16 or g726r24, use the debug voip rtp session named-event 101 command for DTMF-relay debugging.


Tip Be sure to append the argument 101 to the debug voip rtp session named-event command or the console screen will flood with messages and all calls will fail.


Use the debug ccsip all command to enable all SIP debugging capabilities, or use one of the following SIP debug commands:

debug ccsip calls

debug ccsip error

debug ccsip messages

debug ccsip states

In addition, the debug ccsip events command now displays only debugging information specifically related to SIP events. Media stream and SIP service provider interface (SPI) information is now reported in the debug ccsip media and debug ccsip info command output.

Configuration Examples for SIP Support for Media Forking

This section provides the following configuration examples:

SIP Network Using Media Forking Example

Edge Gateway Configuration Example

Party A Configuration Example

Party B Configuration Example

Party C Configuration Example

Party A Initial Call Setup Trace Example

Party B Initial Call Setup Trace Example

Party A Add Second Stream Trace Example

Party C Add Second Stream Trace Example


Note IP addresses and host names in these examples are fictitious.


SIP Network Using Media Forking Example

This section provides a configuration example for a sample SIP network that uses media forking. Figure 3 illustrates the sample network where Party A dials Party B (555-2201). The dial peer for Party B on the originating gateway points to the IP address of SIP_Tester, which is acting as the third-party call controller. The Invite message is sent to SIP_Tester, who then forwards it to Party B. The typical SIP protocol exchange takes place to set up the first stream of the call. The user information portion of the SIP URL for SIP_Tester is 9999, so the dial peers on Party B and Party C are configured with 9999.

SIP_Tester initiates the establishment of the second stream by sending an initial Invite message with no SDP to Party C. Party C rings the terminating phone and responds to SIP_Tester with cause code 183 and an SDP that advertises its media capability. When the terminating phone answers, Party C responds to SIP_Tester with a 200 OK. SIP_Tester creates a re-Invite message with two media lines (m-lines) and sends it to Party A, who creates the second stream to Party C. Party A responds with an ACK that contains its local media information in the SDP. SIP_Tester forwards the ACK with SDP to Party C. A forked call is established.

Figure 3 Sample SIP Network Using Media Forking

Edge Gateway Configuration Example

The edge gateway configuration is used to convert a Foreign Exchange Station (FXS) interface to a T1 interface. It is not involved in media forking or VoIP.

Building configuration...

Current configuration : 4455 bytes
!
version 12.2
no service single-slot-reload-enable
service timestamps debug datetime msec
service timestamps log uptime
no service password-encryption
!
!
logging rate-limit console 10 except errors
!
!
voice-card 1
!
ip subnet-zero
!
!
ip domain-name cisco.com
ip name-server 172.26.11.21
!
no ip dhcp-client network-discovery
isdn switch-type primary-dms100
isdn voice-call-failure 0
call rsvp-sync
!
!
!
controller T1 1/0
 framing esf
 linecode b8zs
 pri-group timeslots 1-24
!
controller T1 1/1
 framing esf
 linecode b8zs
 pri-group timeslots 1-24
!
!
interface Serial1/0:23
 no ip address
 no logging event link-status
 isdn switch-type primary-dms100
 isdn incoming-voice voice
 isdn T310 4000
 no cdp enable
!
interface Serial1/1:23
 no ip address
 no logging event link-status
 isdn switch-type primary-dms100
 isdn incoming-voice voice
 no fair-queue
 no cdp enable
!
interface FastEthernet3/0
 ip address 172.18.193.136 255.255.0.0
 duplex auto
 speed auto
!
ip classless
ip route 172.16.0.0 255.0.0.0 FastEthernet3/0
no ip http server
!
!
!
!
snmp-server packetsize 4096
snmp-server manager
!
voice-port 1/0:23
!
voice-port 1/1:23
!
voice-port 2/0/0
!
voice-port 2/0/1
!
voice-port 2/1/0
!
voice-port 2/1/1
!
dial-peer cor custom
!
!
!
dial-peer voice 5552 pots
 destination-pattern 5552...
 port 1/1:23
 prefix 5552
!
dial-peer voice 5555 pots
 destination-pattern 5555101
 port 2/0/1
!
!
line con 0
 exec-timeout 0 0
 transport preferred none
line aux 0
line vty 0 4
 exec-timeout 0 0
 password lab
 login
!
!
end

Party A Configuration Example

The following is the configuration for Party A.

Building configuration...

Current configuration : 1864 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log uptime
no service password-encryption
!
!
memory-size iomem 10
voice-card 1
 codec complexity high
!
ip subnet-zero
!
!
ip domain-name cisco.com
ip name-server 172.26.11.21
!         
isdn switch-type primary-dms100
isdn voice-call-failure 0
!
!
voice service voip 
 sip
!
!
!
!
!
!
!
no voice hpi capture buffer
no voice hpi capture destination 
!
fax interface-type fax-mail
mta receive maximum-recipients 0
!
controller T1 1/0
 framing esf
 linecode b8zs
!
controller T1 1/1
 framing esf
 linecode b8zs
 pri-group timeslots 1-24
!
!
!
!
interface Ethernet0/0
 ip address 172.18.193.14 255.255.0.0
 half-duplex
 fair-queue 64 256 235
 ip rsvp bandwidth 7500 7500
!
interface Ethernet0/1
 no ip address
 shutdown
 half-duplex
!
interface Serial1/1:23
 no ip address
 no logging event link-status
 isdn switch-type primary-dms100
 isdn incoming-voice voice
 no cdp enable
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.18.193.1
no ip http server
!
!
call rsvp-sync
!
voice-port 1/1:23
!
!
mgcp profile default
!
dial-peer cor custom
!
!
!
dial-peer voice 2100 voip
 destination-pattern 55521..
 session target ipv4:172.18.193.88
!
dial-peer voice 2200 voip
 destination-pattern 55522..
 session protocol sipv2
 session target ipv4:172.18.207.18:5062
 dtmf-relay rtp-nte
 codec g711ulaw
!
dial-peer voice 9999 voip
 destination-pattern 9999
 session protocol sipv2
 session target ipv4:172.18.207.18:5062
!
dial-peer voice 5557 pots
 destination-pattern 55571..
 direct-inward-dial
 port 1/1:23
!
sip-ua 
 retry invite 3
 retry response 3
 retry bye 3
 retry cancel 3
 timers trying 501
!
!
line con 0
 exec-timeout 0 0
 transport preferred none
line aux 0
line vty 0 4
 password lab
 login
line vty 5 15
 login
!
no scheduler allocate
!
end

Party B Configuration Example

The following is the configuration for Party B.

Building configuration...

Current configuration : 1769 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log uptime
no service password-encryption
!
!
memory-size iomem 10
clock timezone gmt 1
ip subnet-zero
!
!
ip domain-name cisco.com
ip name-server 172.26.11.21
!
!
!
interface FastEthernet0/0
 ip address 172.18.193.88 255.255.0.0
 no ip mroute-cache
 duplex auto
 speed auto
 fair-queue 64 256 235
 no cdp enable
 ip rsvp bandwidth 7500 7500
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.18.193.1
no ip http server
!
snmp-server engineID local 00000009020000107BDC8FA0
snmp-server community public RO
snmp-server packetsize 2048
call rsvp-sync
!         
voice-port 1/0/0
 no supervisory disconnect lcfo
!
voice-port 1/0/1
 no supervisory disconnect lcfo
!
dial-peer cor custom
!
!
!
dial-peer voice 2100 pots
 destination-pattern 5552100
 port 1/0/0
!
dial-peer voice 2101 pots
 destination-pattern 5552101
 port 1/0/1
!         
dial-peer voice 2200 pots
 destination-pattern 5552200
 port 1/0/0
!
dial-peer voice 2201 pots
 destination-pattern 5552201
 port 1/0/1
!
dial-peer voice 9999 voip
 destination-pattern 9999
 session protocol sipv2
 session target ipv4:172.18.207.18:5062
 codec g711ulaw
!
sip-ua 
 retry invite 3
 retry response 3
 retry bye 3
 retry cancel 3
 timers trying 501
!
!
line con 0
 exec-timeout 0 0
 transport preferred none
line aux 0
line vty 0 4
 password lab
 login
line vty 5 15
 login
!
!
end

Party C Configuration Example

The following is the configuration for Party C.

Building configuration...

Current configuration : 1638 bytes
!
version 12.2
service timestamps debug datetime msec
service timestamps log uptime
no service password-encryption
!
!
memory-size iomem 10
ip subnet-zero
!
!
ip domain-name cisco.com
ip name-server 172.26.11.21
!
!
!
interface Ethernet0/0
 ip address 172.18.193.80 255.255.0.0
 half-duplex
 fair-queue 64 256 235
 ip rsvp bandwidth 7500 7500
!         
interface Ethernet0/1
 no ip address
 shutdown
 half-duplex
!
ip classless
ip route 0.0.0.0 0.0.0.0 172.18.193.1
no ip http server
!
!
call rsvp-sync
!
voice-port 1/0/0
 no supervisory disconnect lcfo
!
voice-port 1/0/1
 no supervisory disconnect lcfo
!
!
dial-peer cor custom
!         
!
!
dial-peer voice 3100 pots
 destination-pattern 5553100
 port 1/0/0
!
dial-peer voice 3101 pots
 destination-pattern 5553101
 port 1/0/1
!
dial-peer voice 3200 pots
 destination-pattern 5553200
 port 1/0/0
!
dial-peer voice 3201 pots
 destination-pattern 5553201
 port 1/0/1
!
dial-peer voice 9999 voip
 destination-pattern 9999
 session protocol sipv2
 session target ipv4:172.18.207.18:5062
 dtmf-relay rtp-nte
 codec g711ulaw
!
sip-ua 
 retry invite 3
 retry response 3
 retry bye 3
 retry cancel 3
!
!
line con 0
 exec-timeout 0 0
 transport preferred none
line aux 0
line vty 0 4
 exec-timeout 0 0
 password lab
 login
 transport input none
 escape-character BREAK
line vty 5 15
 login
!
!
end

Party A Initial Call Setup Trace Example

The following is the initial call setup trace for Party A using the debug ccsip message command.

*Mar  1 00:32:02.431: Sent: 
INVITE sip:5552201@172.18.207.18:5062;user=phone SIP/2.0
Via: SIP/2.0/UDP  172.18.193.14:5060
From: "5555101" <sip:5555101@172.18.193.14>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>
Date: Mon, 01 Mar 1993 00:32:02 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
Supported: timer,100rel
Min-SE:  1800
Cisco-Guid: 27401485-351474124-2149117103-281843893
User-Agent: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Max-Forwards: 6
Timestamp: 730945922
Contact: <sip:5555101@172.18.193.14:5060;user=phone>
Expires: 180
Allow-Events: telephone-event
Content-Type: application/sdp
Content-Length: 299

v=0
o=CiscoSystemsSIP-GW-UserAgent 2763 7166 IN IP4 172.18.193.14
s=SIP Call
c=IN IP4 172.18.193.14
t=0 0
m=audio 16412 RTP/AVP 0 100 101
c=IN IP4 172.18.193.14
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20

*Mar  1 00:32:02.499: Received: 
SIP/2.0 183 Session Progress
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "5555101" <sip:5555101@172.18.193.14;user=phone>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
CSeq: 101 INVITE
Require: 100rel
RSeq: 5413
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Type: application/sdp
Content-Length: 223

v=0
o=SIP_Tester 1239625037 1770029373 IN IP4 172.18.207.18
s=SIP Prot Test Call
t=0 0
m=audio 17236 RTP/AVP 0 100
c=IN IP4 172.18.193.88
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

*Mar  1 00:32:02.539: Sent: 
PRACK sip:9999@172.18.207.18:5062;user=phone SIP/2.0
Via: SIP/2.0/UDP  172.18.193.14:5060
From: "5555101" <sip:5555101@172.18.193.14>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
Date: Mon, 01 Mar 1993 00:32:02 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
CSeq: 102 PRACK
RAck: 5413 101 INVITE
Content-Length: 0

*Mar  1 00:32:02.563: Received: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "5555101" <sip:5555101@172.18.193.14;user=phone>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
CSeq: 102 PRACK
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Length: 0

*Mar  1 00:32:03.609: Received: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "5555101" <sip:5555101@172.18.193.14;user=phone>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
CSeq: 101 INVITE
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Type: application/sdp
Content-Length: 223

v=0
o=SIP_Tester 1239625037 1770029374 IN IP4 172.18.207.18
s=SIP Prot Test Call
t=0 0
m=audio 17236 RTP/AVP 0 100
c=IN IP4 172.18.193.88
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

*Mar  1 00:32:03.633: Sent: 
ACK sip:9999@172.18.207.18:5062;user=phone SIP/2.0
Via: SIP/2.0/UDP  172.18.193.14:5060
From: "5555101" <sip:5555101@172.18.193.14>;tag=1D556B-24F1
To: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
Date: Mon, 01 Mar 1993 00:32:02 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
Max-Forwards: 6
Content-Length: 0
CSeq: 101 ACK

Party B Initial Call Setup Trace Example

The following is the initial call setup trace for Party B using the debug ccsip message command. Also, call status is displayed with the show sip-ua calls command.

*Mar  1 00:43:13.655: Received: 
INVITE sip:5552201@172.18.193.88;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 487666621@172.18.207.18
Supported: 100rel
CSeq: 101 INVITE
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Type: application/sdp
Content-Length: 278

v=0
o=SIP_Tester 1818337819 831652457 IN IP4 172.18.207.18
s=SIP Prot Test Call
t=0 0
m=audio 16452 RTP/AVP 0 100 101
c=IN IP4 172.18.193.14
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20

*Mar  1 00:43:13.683: Sent: 
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 00:43:13 gmt
Call-ID: 487666621@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Content-Length: 0



*Mar  1 00:43:13.715: Sent: 
SIP/2.0 183 Session Progress
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 00:43:13 gmt
Call-ID: 487666621@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Require: 100rel
RSeq: 5450
Allow-Events: telephone-event
Contact: <sip:5552201@172.18.193.88:5060;user=phone>
Content-Type: application/sdp
Content-Disposition: session;handling=required
Content-Length: 243

v=0
o=CiscoSystemsSIP-GW-UserAgent 1886 7999 IN IP4 172.18.193.88
s=SIP Call
c=IN IP4 172.18.193.88
t=0 0
m=audio 17936 RTP/AVP 0 100
c=IN IP4 172.18.193.88
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

*Mar  1 00:43:13.779: Received: 
PRACK sip:5552201@172.18.193.88;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 487666621@172.18.207.18
CSeq: 102 PRACK
RAck: 0 101 INVITE
Content-Length: 0



*Mar  1 00:43:13.791: Sent: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 00:43:13 gmt
Call-ID: 487666621@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 102 PRACK
Content-Length: 0



*Mar  1 00:43:17.251: Sent: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 00:43:13 gmt
Call-ID: 487666621@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Contact: <sip:5552201@172.18.193.88:5060;user=phone>
Content-Type: application/sdp
Content-Length: 243

v=0
o=CiscoSystemsSIP-GW-UserAgent 1886 7999 IN IP4 172.18.193.88
s=SIP Call
c=IN IP4 172.18.193.88
t=0 0
m=audio 17936 RTP/AVP 0 100
c=IN IP4 172.18.193.88
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

*Mar  1 00:43:17.343: Received: 
ACK sip:5552201@172.18.193.88;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5552201" <sip:5552201@172.18.193.88;user=phone>;tag=279390-CB
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 487666621@172.18.207.18
CSeq: 101 ACK
Content-Length: 0


show sip-ua calls

SIP UAC CALL INFO

   Number of UAC calls: 0

SIP UAS CALL INFO

Call 1
SIP Call ID                : 487666621@172.18.207.18
   State of the call       : STATE_ACTIVE (6)
   Substate of the call    : SUBSTATE_NONE (0)
   Calling Number          : 9999
   Called Number           : 5552201
   Bit Flags               : 0x1212003A 0x20000
   Source IP Address (Sig ): 172.18.193.88
   Destn SIP Req Addr:Port : 172.18.207.18:5062
   Destn SIP Resp Addr:Port: 172.18.207.18:5062
   Destination Name        : 172.18.207.18
   Number of Media Streams : 1
   Number of Active Streams: 1
   RTP Fork Object         : 0x0
   Media Stream 1 
    State of the stream : STREAM_ACTIVE (5) 
    Stream Call ID : 9 
    Stream Type : voice-only (0) 
    Negotiated Codec : g711ulaw (160 bytes) 
    Codec Payload Type : 0 
    Negotiated Dtmf-relay : inband-voice (0) 
    Dtmf-relay Payload : 0 
    Media Source IP Addr:Port: 172.18.193.88:17936 
    Media Dest IP Addr:Port : 172.18.193.14:16452 
   Number of UAS calls: 1

Party A Add Second Stream Trace Example

The following is the second stream trace added by Party A. Also, call status is displayed with the show sip-ua calls command.

*Mar  1 00:33:05.178: Received: 
INVITE sip:5555101@172.18.193.14;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
To: "5555101" <sip:5555101@172.18.193.14;user=phone>;tag=1D556B-24F1
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
Supported: 100rel
CSeq: 101 INVITE
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Type: application/sdp
Content-Length: 635

v=0
o=SIP_Tester 1239625037 1770029375 IN IP4 172.18.207.18
s=SIP Prot Test Call
t=0 0
m=audio 17236 RTP/AVP 0 100
c=IN IP4 172.18.193.88
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20
m=audio 17114 RTP/AVP 0 100 101 101 100
c=IN IP4 172.18.193.80
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194

*Mar  1 00:33:05.222: Sent: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
To: "5555101" <sip:5555101@172.18.193.14>;tag=1D556B-24F1
Date: Mon, 01 Mar 1993 00:33:05 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Contact: <sip:5555101@172.18.193.14:5060;user=phone>
Content-Type: application/sdp
Content-Length: 431

v=0
o=CiscoSystemsSIP-GW-UserAgent 2763 7167 IN IP4 172.18.193.14
s=SIP Call
c=IN IP4 172.18.193.14
t=0 0
m=audio 16412 RTP/AVP 0 100
c=IN IP4 172.18.193.14
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20
m=audio 18802 RTP/AVP 0 101 100
c=IN IP4 172.18.193.14
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

*Mar  1 00:33:05.234: Received: 
ACK sip:5555101@172.18.193.14;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: <sip:5552201@172.18.207.18;user=phone>;tag=tester-tag
To: "5555101" <sip:5555101@172.18.193.14;user=phone>;tag=1D556B-24F1
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
CSeq: 101 ACK
Content-Length: 0



show sip-ua calls 
SIP UAC CALL INFO

Call 1
SIP Call ID                : 1A3F2B6-14F311CC-801AECAF-10CC98B5@172.18.193.14
   State of the call       : STATE_ACTIVE (6)
   Substate of the call    : SUBSTATE_NONE (0)
   Calling Number          : 5555101
   Called Number           : 5552201
   Bit Flags               : 0x12120030 0x20000
   Source IP Address (Sig ): 172.18.193.14
   Destn SIP Req Addr:Port : 172.18.207.18:5062
   Destn SIP Resp Addr:Port: 172.18.207.18:5062
   Destination Name        : 172.18.207.18
   Number of Media Streams : 2
   Number of Active Streams: 2
   RTP Fork Object         : 0x83064DC8
   Media Stream 1 
    State of the stream : STREAM_ACTIVE (5) 
    Stream Call ID : 11 
    Stream Type : voice-only (0) 
    Negotiated Codec : g711ulaw (160 bytes) 
    Codec Payload Type : 0 
    Negotiated Dtmf-relay : inband-voice (0) 
    Dtmf-relay Payload : 0 
    Media Source IP Addr:Port: 172.18.193.14:16412 
    Media Dest IP Addr:Port : 172.18.193.88:17236 
   Media Stream 2 
    State of the stream : STREAM_ACTIVE (5) 
    Stream Call ID : 12 
    Stream Type : voice+dtmf (1) 
    Negotiated Codec : g711ulaw (160 bytes) 
    Codec Payload Type : 0 
    Negotiated Dtmf-relay : rtp-nte (6) 
    Dtmf-relay Payload : 101 
    Media Source IP Addr:Port: 172.18.193.14:18802 
    Media Dest IP Addr:Port : 172.18.193.80:17114 

   Number of UAC calls: 1

SIP UAS CALL INFO

   Number of UAS calls: 0

Party C Add Second Stream Trace Example

The following is the second stream trace added by Party C. Also, call status is displayed with the show sip-ua calls command.

*Mar  1 00:44:19.763: Received: 
INVITE sip:5553201@172.18.193.80;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5553201" <sip:5553201@172.18.193.80;user=phone>
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 2108310431@172.18.207.18
Supported: 100rel
CSeq: 101 INVITE
Contact: <sip:9999@172.18.207.18:5062;user=phone>
Content-Length: 0

*Mar  1 00:44:19.792: Sent: 
SIP/2.0 100 Trying
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5553201" <sip:5553201@172.18.193.80;user=phone>;tag=2895C8-53B
Date: Mon, 01 Mar 1993 00:44:19 GMT
Call-ID: 2108310431@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Content-Length: 0

*Mar  1 00:44:19.828: Sent: 
SIP/2.0 183 Session Progress
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5553201" <sip:5553201@172.18.193.80;user=phone>;tag=2895C8-53B
Date: Mon, 01 Mar 1993 00:44:19 GMT
Call-ID: 2108310431@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Require: 100rel
RSeq: 6083
Allow-Events: telephone-event
Contact: <sip:5553201@172.18.193.80:5060;user=phone>
Content-Type: application/sdp
Content-Disposition: session;handling=required
Content-Length: 523

v=0
o=CiscoSystemsSIP-GW-UserAgent 8259 5683 IN IP4 172.18.193.80
s=SIP Call
c=IN IP4 172.18.193.80
t=0 0
m=audio 18988 RTP/AVP 0 100 101
c=IN IP4 172.18.193.80
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20

*Mar  1 00:44:20.985: Sent: 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5553201" <sip:5553201@172.18.193.80;user=phone>;tag=2895C8-53B
Date: Mon, 01 Mar 1993 00:44:19 GMT
Call-ID: 2108310431@172.18.207.18
Server: Cisco-SIPGateway/IOS-12.x
CSeq: 101 INVITE
Allow-Events: telephone-event
Contact: <sip:5553201@172.18.193.80:5060;user=phone>
Content-Type: application/sdp
Content-Length: 523

v=0
o=CiscoSystemsSIP-GW-UserAgent 8259 5683 IN IP4 172.18.193.80
s=SIP Call
c=IN IP4 172.18.193.80
t=0 0
m=audio 18988 RTP/AVP 0 100 101
c=IN IP4 172.18.193.80
a=rtpmap:0 PCMU/8000
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=ptime:20

*Mar  1 00:44:20.997: Received: 
ACK sip:5553201@172.18.193.80;user=phone SIP/2.0
Via: SIP/2.0/UDP 172.18.207.18:5062
From: "SIP_Tester" <sip:9999@172.18.207.18:5062;user=phone>;tag=tester-tag
To: "5553201" <sip:5553201@172.18.193.80;user=phone>;tag=2895C8-53B
Date: Mon, 01 Mar 1993 01:01:01 GMT
Call-ID: 2108310431@172.18.207.18
CSeq: 101 ACK
Content-Type: application/sdp
Content-Length: 277

v=0
o=SIP_Tester 2029259292 42666129 IN IP4 172.18.207.18
s=SIP Prot Test Call
t=0 0
m=audio 16728 RTP/AVP 0 101 100
c=IN IP4 172.18.193.14
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=rtpmap:100 X-NSE/8000
a=fmtp:100 192-194
a=ptime:20

show sip-ua calls 
SIP UAC CALL INFO

   Number of UAC calls: 0

SIP UAS CALL INFO

Call 1
SIP Call ID                : 186464186@172.18.207.18
   State of the call       : STATE_ACTIVE (6)
   Substate of the call    : SUBSTATE_NONE (0)
   Calling Number          : 9999
   Called Number           : 5553201
   Bit Flags               : 0x1212003A 0x20000
   Source IP Address (Sig ): 172.18.193.80
   Destn SIP Req Addr:Port : 172.18.207.18:5062
   Destn SIP Resp Addr:Port: 172.18.207.18:5062
   Destination Name        : 172.18.207.18
   Number of Media Streams : 1
   Number of Active Streams: 1
   RTP Fork Object         : 0x0
   Media Stream 1
    State of the stream : STREAM_ACTIVE (5) 
    Stream Call ID : 7 
    Stream Type : voice+dtmf (1) 
    Negotiated Codec : g711ulaw (160 bytes) 
    Codec Payload Type : 0 
    Negotiated Dtmf-relay : rtp-nte (6) 
    Dtmf-relay Payload : 101 
    Media Source IP Addr:Port: 172.18.193.80:19352 
    Media Dest IP Addr:Port : 172.18.193.14:16770

   Number of UAS calls: 1

Additional References

For additional information related to the SIP Support for Media Forking feature, refer to the following references:

Related Documents

Related Topic
Document Title

Cisco SIP Functionality

Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2

Cisco IOS Voice, Video, and Fax Command Reference, Release 12.2 T

Session Initiation Protocol (SIP) for VoIP, Release 12.2(8)T

Session Initiation Protocol Gateway Call Flows, Release 12.2(4)T

Call Transfer Capabilities Using the Refer Method, Release 12.2(8)T

SIP Media Inactivity Timer, Release 12.2(8)T

Dual Tone Multifrequency Relay for SIP Calls Using Named Telephone Events, Release 12.2(2)XB

Cisco IOS References

Cisco IOS Debug Command Reference, Release 12.2 T

Cisco IOS IP Configuration Guide, Release 12.2

Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.2 T

Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols, Release 12.2 T

Cisco IOS IP Command Reference, Volume 3 of 3: Multicast, Release 12.2 T

Cisco IOS Dial Technologies Configuration Guide, Release 12.2


Standards

Standards1
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

1 Not all supported standards are listed.


MIBs

MIBs1
MIBs Link

CISCO-SIP-UA-MIB

To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

1 Not all supported MIBs are listed.


To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://tools.cisco.com/ITDIT/MIBS/servlet/index

If Cisco MIB Locator does not support the MIB information that you need, you can also obtain a list of supported MIBs and download MIBs from the Cisco MIBs page at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

To access Cisco MIB Locator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:

http://www.cisco.com/register

RFCs


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/public/support/tac/home.shtml


Command Reference

This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 T command reference publications.

New Commands

debug ccsip info

debug ccsip media

show sip-ua calls

Modified Commands

debug ccsip events

debug ccsip events

To enable tracing of events that are specific to SIP service provider interface (SPI), use the debug ccsip events command in privileged EXEC mode. To disable debugging output, use the no form of this command.

debug ccsip events

no debug ccsip events

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

12.1(1)T

This command was introduced.

12.1(3)T

The output of this command was changed.

12.2(2)XA

Support was added for the Cisco AS5350 and Cisco AS5400.

12.2(2)XB1

This command was introduced on the Cisco AS5850.

12.2(11)T

This command was integrated into Cisco IOS Release 12.2(11)T.

12.2(15)T

Much of the information formerly found in the output of the debug ccsip events command is now reported in the output of the debug ccsip info and debug ccsip media commands. The debug ccsip events command now displays only the debug information specifically related to SIP events.


Usage Guidelines

This command previously traced all events posted to SIP SPI from all interfaces and also provided general SIP SPI information. Beginning with Cisco IOS Release 12.2(15)T, the debug ccsip events command displays only debugging information specifically related to SIP SPI events. Media stream and SIP SPI information is now reported in the debug ccsip media and debug ccsip info command output.

Examples

The following is sample output from the debug ccsip events command for a Cisco 3660:

Router# debug ccsip events

SIP Call events tracing is enabled 
Router# 
Nov 15 18:20:25.779: Queued event from SIP SPI : SIPSPI_EV_CC_CALL_SETUP 
Nov 15 18:20:25.779: Queued event from SIP SPI : SIPSPI_EV_CREATE_CONNECTION 
Nov 15 18:20:25.783: Queued event from SIP SPI : SIPSPI_EV_SEND_MESSAGE 
Nov 15 18:20:25.815: Queued event from SIP SPI : SIPSPI_EV_CREATE_CONNECTION 
Nov 15 18:20:25.819: Queued event from SIP SPI : SIPSPI_EV_SEND_MESSAGE 
Nov 15 18:20:28.339: Queued event from SIP SPI : SIPSPI_EV_CLOSE_CONNECTION 
Nov 15 18:20:28.339: Queued event from SIP SPI : SIPSPI_EV_SEND_MESSAGE 
Nov 15 18:20:50.844: Queued event from SIP SPI : SIPSPI_EV_CLOSE_CONNECTION 
Nov 15 18:20:50.844: Queued event from SIP SPI : SIPSPI_EV_SEND_MESSAGE 
Nov 15 18:20:50.848: Queued event from SIP SPI : SIPSPI_EV_CC_CALL_DISCONNECT 

Related Commands

Command
Description

debug ccsip all

Enables all SIP-related debugging.

debug ccsip info

Enables tracing of general SIP SPI information.

debug ccsip media

Enables tracing of SIP call media streams.


debug ccsip info

To enable tracing of general SIP service provider interface (SPI) information, use the debug ccsip info command in privileged EXEC mode. To disable debugging output, use the no form of this command.

debug ccsip info

no debug ccsip info

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

Beginning in Cisco IOS Release 12.2(15)T, the debug ccsip info command is a separate option that displays general SIP SPI information for debug purposes. In past releases, this output was part of the debug ccsip events command.

Examples

The following is sample output from the debug ccsip info command for a Cisco 3660:

Router# debug ccsip info 

SIP Call info tracing is enabled 
Router# 
Nov 15 18:19:22.670: ****Adding to UAC table
Nov 15 18:19:22.670: adding call id E to table
Nov 15 18:19:22.670: CCSIP-SPI-CONTROL: act_idle_call_setup 
Nov 15 18:19:22.670: act_idle_call_setup:Not using Voice Class Codec
Nov 15 18:19:22.670: act_idle_call_setup: preferred_codec set[0] type :g729r8 bytes: 20 
Nov 15 18:19:22.670: sipSPICopyPeerDataToCCB: From CLI: Modem NSE payload = 100, 
Passthrough = 0,Modem relay = 0, Gw-Xid = 1 
SPRT latency 200, SPRT Retries = 12, Dict Size = 1024 
String Len = 32, Compress dir = 3 
Nov 15 18:19:22.670: ****Deleting from UAC table
Nov 15 18:19:22.670: ****Adding to UAC table
Nov 15 18:19:22.670: sipSPIUsetBillingProfile: sipCallId for billing records = 
20A40C3B-D92C11D5-8015E1CC-C91F3F10@12.18.195.49 
Nov 15 18:19:22.674: CCSIP-SPI-CONTROL: act_idle_connection_created 
Nov 15 18:19:22.674: CCSIP-SPI-CONTROL: act_idle_connection_created: Connid(1) created to 
172.18.193.190:5060, local_port 56981 
Nov 15 18:19:22.674: CCSIP-SPI-CONTROL: sipSPIOutgoingCallSDP 
Nov 15 18:19:22.674: convert_codec_bytes_to_ptime: Values :Codec: g729r8 codecbytes :20, 
ptime: 10
Nov 15 18:19:22.674: sip_generate_sdp_xcaps_list: Modem Relay disabled. X-cap not needed
Nov 15 18:19:22.674: sipSPIAddLocalContact 
Nov 15 18:19:22.674: sip_stats_method 
Nov 15 18:19:22.690: HandleUdpSocketReads :Msg enqueued for SPI with IPaddr: 
172.18.193.190:5060 
Nov 15 18:19:22.690: CCSIP-SPI-CONTROL: act_sentinvite_new_message 
Nov 15 18:19:22.690: CCSIP-SPI-CONTROL: sipSPICheckResponse 
Nov 15 18:19:22.690: sip_stats_status_code 
Nov 15 18:19:22.690: Roundtrip delay 16 milliseconds for method INVITE
Nov 15 18:19:22.706: HandleUdpSocketReads :Msg enqueued for SPI with IPaddr: 
172.18.193.190:5060 
Nov 15 18:19:22.706: CCSIP-SPI-CONTROL: act_recdproc_new_message 
Nov 15 18:19:22.706: CCSIP-SPI-CONTROL: sipSPICheckResponse 
Nov 15 18:19:22.706: sip_stats_status_code 
Nov 15 18:19:22.706: Roundtrip delay 32 milliseconds for method INVITE
Nov 15 18:19:22.706: sipSPIGetSdpBody : Parse incoming session description 
Nov 15 18:19:22.706: HandleSIP1xxSessionProgress: Content-Disposition received in 18x 
response:session;handling=required 
Nov 15 18:19:22.706: sipSPIDoMediaNegotiation: number of m lines is 1 
Nov 15 18:19:22.706: sipSPIDoAudioNegotiation: Codec (g729r8) Negotiation Successful on 
Static Payload
Nov 15 18:19:22.706: sipSPIDoPtimeNegotiation: One ptime attribute found - value:10 
Nov 15 18:19:22.706: convert_ptime_to_codec_bytes: Values :Codec: g729r8 ptime :10, 
codecbytes: 20
Nov 15 18:19:22.710: convert_codec_bytes_to_ptime: Values :Codec: g729r8 codecbytes :20, 
ptime: 10
Nov 15 18:19:22.710: sipSPIDoDTMFRelayNegotiation: m-line index 1 
Nov 15 18:19:22.710: sipSPIDoDTMFRelayNegotiation: Requested DTMF-RELAY option(s) not 
found in Preferred DTMF-RELAY option list! 
Nov 15 18:19:22.710: sip_sdp_get_modem_relay_cap_params: 
Nov 15 18:19:22.710: sip_sdp_get_modem_relay_cap_params: NSE payload from X-cap = 0 
Nov 15 18:19:22.710: sip_do_nse_negotiation: NSE Payload 100 found in SDP 
Nov 15 18:19:22.710: sip_do_nse_negotiation: Remote NSE payload = local one = 100, Use it 
Nov 15 18:19:22.710: sip_select_modem_relay_params: X-tmr not present in SDP. Disable 
modem relay 
Nov 15 18:19:22.710: sipSPIDoQoSNegotiation - SDP body with media description 
Nov 15 18:19:22.710: ccsip_process_response_contact_record_route 
Nov 15 18:19:22.710: CCSIP-SPI-CONTROL: ccsip_bridge: confID = 4, srcCallID = 14, 
dstCallID = 13 
Nov 15 18:19:22.710: sipSPIUupdateCcCallIds: old src/dest ccCallids: -1/-1, new src/dest 
ccCallids: 14/13 
Nov 15 18:19:22.710: sipSPIUupdateCcCallIds: old streamcallid=-1, new streamcallid=14 
Nov 15 18:19:22.710: CCSIP-SPI-CONTROL: ccsip_caps_ind 
Nov 15 18:19:22.710: ccsip_get_rtcp_session_parameters: CURRENT VALUES: stream_callid=14, 
current_seq_num=0x1B1B 
Nov 15 18:19:22.710: ccsip_get_rtcp_session_parameters: NEW VALUES: stream_callid=14, 
current_seq_num=0x180C 
Nov 15 18:19:22.710: ccsip_caps_ind: Load DSP with negotiated codec : g729r8, Bytes=20 
Nov 15 18:19:22.710: ccsip_caps_ind: set forking flag to 0x0 
Nov 15 18:19:22.710: sipSPISetDTMFRelayMode: set DSP for dtmf-relay = 
CC_CAP_DTMF_RELAY_INBAND_VOICE_AND_OOB 
Nov 15 18:19:22.710: sip_set_modem_caps: Negotiation already Done. Set negotiated Modem 
caps 
Nov 15 18:19:22.710: sip_set_modem_caps: Modem Relay & Passthru both disabled 
Nov 15 18:19:22.710: sip_set_modem_caps: nse payload = 100, ptru mode = 0, ptru-codec=0, 
redundancy=0, xid=0, relay=0, sprt-retry=12, latecncy=200, compres-dir=3, dict=1024, 
strnlen=32 
Nov 15 18:19:22.710: ccsip_caps_ind: Load DSP with codec : g729r8, Bytes=20 
Nov 15 18:19:22.710: CCSIP-SPI-CONTROL: ccsip_caps_ack 
Nov 15 18:19:22.710: ccsip_caps_ack: set forking flag to 0x60FD1EAC 
Nov 15 18:19:22.710: CCSIP-SPI-CONTROL: act_recdproc_connection_created 
Nov 15 18:19:22.710: CCSIP-SPI-CONTROL: sipSPICheckSocketConnection: Connid(2) created to 
172.18.193.190:5060, local_port 51663 
Nov 15 18:19:22.714: sip_stats_method 
Nov 15 18:19:22.722: HandleUdpSocketReads :Msg enqueued for SPI with IPaddr: 
172.18.193.190:5060 
Nov 15 18:19:22.722: CCSIP-SPI-CONTROL: act_recdproc_new_message 
Nov 15 18:19:22.722: CCSIP-SPI-CONTROL: sipSPICheckResponse 
Nov 15 18:19:22.722: sip_stats_status_code 
Nov 15 18:19:22.722: Roundtrip delay 48 milliseconds for method PRACK
Nov 15 18:19:24.706: HandleUdpSocketReads :Msg enqueued for SPI with IPaddr: 
172.18.193.190:5060 
Nov 15 18:19:24.706: CCSIP-SPI-CONTROL: act_recdproc_new_message 
Nov 15 18:19:24.706: CCSIP-SPI-CONTROL: sipSPICheckResponse 
Nov 15 18:19:24.706: sip_stats_status_code 
Nov 15 18:19:24.706: Roundtrip delay 2032 milliseconds for method PRACK
Nov 15 18:19:24.706: sipSPIGetSdpBody : Parse incoming session description 
Nov 15 18:19:24.710: CCSIP-SPI-CONTROL: sipSPIUACSessionTimer 
Nov 15 18:19:24.710: CCSIP-SPI-CONTROL: act_recdproc_continue_200_processing 
Nov 15 18:19:24.710: CCSIP-SPI-CONTROL: act_recdproc_continue_200_processing: *** This ccb 
is the parent
Nov 15 18:19:24.710: sipSPICompareRespMediaInfo 
Nov 15 18:19:24.710: sipSPIDoMediaNegotiation: number of m lines is 1 
Nov 15 18:19:24.710: sipSPIDoAudioNegotiation: Codec (g729r8) Negotiation Successful on 
Static Payload
Nov 15 18:19:24.710: sipSPIDoPtimeNegotiation: One ptime attribute found - value:10 
Nov 15 18:19:24.710: convert_ptime_to_codec_bytes: Values :Codec: g729r8 ptime :10, 
codecbytes: 20
Nov 15 18:19:24.710: convert_codec_bytes_to_ptime: Values :Codec: g729r8 codecbytes :20, 
ptime: 10
Nov 15 18:19:24.710: sipSPIDoDTMFRelayNegotiation: m-line index 1 
Nov 15 18:19:24.710: sipSPIDoDTMFRelayNegotiation: Requested DTMF-RELAY option(s) not 
found in Preferred DTMF-RELAY option list! 
Nov 15 18:19:24.710: sip_sdp_get_modem_relay_cap_params: 
Nov 15 18:19:24.710: sip_sdp_get_modem_relay_cap_params: NSE payload from X-cap = 0 
Nov 15 18:19:24.710: sip_do_nse_negotiation: NSE Payload 100 found in SDP 
Nov 15 18:19:24.710: sip_do_nse_negotiation: Remote NSE payload = local one = 100, Use it 
Nov 15 18:19:24.710: sip_select_modem_relay_params: X-tmr not present in SDP. Disable 
modem relay 
Nov 15 18:19:24.710: sipSPIProcessMediaChanges 
Nov 15 18:19:24.710: ccsip_process_response_contact_record_route 
Nov 15 18:19:24.710: CCSIP-SPI-CONTROL: sipSPIProcess200OKforinvite 
Nov 15 18:19:24.710: sip_stats_method 
Nov 15 18:19:24.710: udpsock_close_connect: Socket fd: 1 closed for connid 1 with remote 
port: 5060 
Nov 15 18:19:37.479: HandleUdpSocketReads :Msg enqueued for SPI with IPaddr: 
172.18.193.190:52180 
Nov 15 18:19:37.483: ****Found CCB in UAC table
Nov 15 18:19:37.483: CCSIP-SPI-CONTROL: act_active_new_message 
Nov 15 18:19:37.483: CCSIP-SPI-CONTROL: sact_active_new_message_request 
Nov 15 18:19:37.483: sip_stats_method 
Nov 15 18:19:37.483: sip_stats_status_code 
Nov 15 18:19:37.483: CCSIP-SPI-CONTROL: sipSPIInitiateCallDisconnect : Initiate call 
disconnect(16) for outgoing call 
Nov 15 18:19:37.483: udpsock_close_connect: Socket fd: 2 closed for connid 2 with remote 
port: 5060 
Nov 15 18:19:37.483: CCSIP-SPI-CONTROL: act_disconnecting_disconnect 
Nov 15 18:19:37.483: CCSIP-SPI-CONTROL: sipSPICallCleanup 
Nov 15 18:19:37.483: sipSPIIcpifUpdate :CallState: 4 Playout: 10230 DiscTime:1745148 
ConnTime 1743871
Nov 15 18:19:37.483: ****Deleting from UAC table
Nov 15 18:19:37.483: Removing call id E
Nov 15 18:19:37.483: freeing ccb 63330954

Related Commands

Command
Description

debug ccsip all

Enables all SIP-related debugging.

debug ccsip events

Enables tracing of events that are specific to SIP SPI.

debug ccsip media

Enables tracing of SIP call media streams.



debug ccsip media

To enable tracing of SIP call media streams, use the debug ccsip media command in privileged EXEC mode. To disable debugging output, use the no form of this command.

debug ccsip media

no debug ccsip media

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

Beginning in Cisco IOS Release 12.2(15)T, the debug ccsip media command is a separate option that displays debugging information specific to SIP media stream processing. In past releases, this output was part of the debug ccsip events command.

Examples

The following is sample output from the debug ccsip media command for a Cisco 3660:

Router# debug ccsip media 

SIP Call media tracing is enabled 
Router# 
Nov 15 18:19:53.835: sipSPISetMediaSrcAddr: media src addr for stream 1 = 172.18.195.49 
Nov 15 18:19:53.835: sipSPIReserveRtpPort: reserved port 16500 for stream 1 
Nov 15 18:19:53.867: sipSPIReplaceSDP 
Nov 15 18:19:53.871: sipSPICopySdpInfo 
Nov 15 18:19:53.871: sipSPIUpdCallWithSdpInfo: 
Preferred Codec : g729r8, bytes :20 
Preferred DTMF relay : inband-voice 
Preferred NTE payload : 101 
Early Media : No 
Delayed Media : No 
Bridge Done : No 
New Media : No 
DSP DNLD Reqd : No
Nov 15 18:19:53.871: sipSPISetMediaSrcAddr: media src addr for stream 1 = 172.18.195.49 
Nov 15 18:19:53.871: sipSPIUpdCallWithSdpInfo: 
M-line Index : 1 
State : STREAM_ADDING (3) 
Callid : -1 
Negotiated Codec : g729r8, bytes :20 
Negotiated DTMF relay : inband-voice 
Negotiated NTE payload : 0 
Media Srce Addr/Port : 172.18.195.49:16500 
Media Dest Addr/Port : 172.18.193.190:19148
Nov 15 18:19:53.871: sipSPIProcessRtpSessions 
Nov 15 18:19:53.871: sipSPIAddStream: Adding stream 1 (callid 16) to the VOIP RTP library 
Nov 15 18:19:53.871: sipSPISetMediaSrcAddr: media src addr for stream 1 = 172.18.195.49 
Nov 15 18:19:53.871: sipSPIUpdateRtcpSession: for m-line 1 
Nov 15 18:19:53.871: sipSPIUpdateRtcpSession: rtcp_session info 
laddr = 172.18.195.49, lport = 16500, raddr = 172.18.193.190, rport=19148 
Nov 15 18:19:53.871: sipSPIUpdateRtcpSession: No rtp session, creating a new one
Nov 15 18:19:53.871: sipSPISetStreamInfo: num_streams = 1 
Nov 15 18:19:53.871: sipSPISetStreamInfo: adding stream type 0 from mline 1 
Nov 15 18:19:53.871: sipSPISetStreamInfo: caps.stream_count=1, 
caps.stream[0].stream_type=0x1, caps.stream_list.xmitFunc=voip_rtp_xmit, 
caps.stream_list.context=0x634F1F2C (gccb) 
Nov 15 18:19:55.555: sipSPICompareSDP 
Nov 15 18:19:55.555: sipSPICompareStreams: stream 1 dest_port: old=19148 new=19148 
Nov 15 18:19:55.555: sipSPICompareStreams: Flags set for stream 1: RTP_CHANGE=No 
CAPS_CHANGE=No 
Nov 15 18:19:55.555: sipSPICompareSDP: Flags set for call: NEW_MEDIA=No DSPDNLD_REQD=No 
Nov 15 18:19:55.555: sipSPIReplaceSDP 
Nov 15 18:19:55.555: sipSPICopySdpInfo 
Nov 15 18:19:55.555: sipSPIUpdCallWithSdpInfo: 
Preferred Codec : g729r8, bytes :20 
Preferred DTMF relay : inband-voice 
Preferred NTE payload : 101 
Early Media : No 
Delayed Media : No 
Bridge Done : Yes 
New Media : No 
DSP DNLD Reqd : No
Nov 15 18:19:55.555: sipSPISetMediaSrcAddr: media src addr for stream 1 = 172.18.195.49 
Nov 15 18:19:55.555: sipSPIUpdCallWithSdpInfo: 
M-line Index : 1 
State : STREAM_ACTIVE (3) 
Callid : 16 
Negotiated Codec : g729r8, bytes :20 
Negotiated DTMF relay : inband-voice 
Negotiated NTE payload : 0 
Media Srce Addr/Port : 172.18.195.49:16500 
Media Dest Addr/Port : 172.18.193.190:19148

Related Commands

Command
Description

debug ccsip all

Enables all SIP-related debugging.

debug ccsip events

Enables tracing of events that are specific to SIP SPI.

debug ccsip info

Enables tracing of general SIP SPI events.


show sip-ua calls

To display active user agent client (UAC) and user agent server (UAS) information on SIP calls, use the show sip-ua calls command in privileged EXEC mode.

show sip-ua calls

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

The show sip-ua calls command displays active UAC and UAS information on SIP calls. It includes information about multiple media streams, up to three media streams if it is a media-forked call. It is useful in debugging multiple media streams because it is the only command that indicates whether an active call is forked.

Examples

The following is sample output from the show sip-ua calls command for a Cisco 3660:

Router# show sip-ua calls

SIP UAC CALL INFO

Call 1 
SIP Call ID : 515205D4-20B711D6-8015FF77-1973C402@172.18.195.49 
 State of the call : STATE_ACTIVE (6) 
 Substate of the call : SUBSTATE_NONE (0) 
 Calling Number : 5550200 
 Called Number : 5551101 
 Bit Flags : 0x12120030 0x220000 
 Source IP Address (Sig ): 172.18.195.49 
 Destn SIP Req Addr:Port : 172.18.207.18:5063 
 Destn SIP Resp Addr:Port: 172.18.207.18:5063 
 Destination Name : 172.18.207.18 
 Number of Media Streams : 4 
 Number of Active Streams: 3 
 RTP Fork Object : 0x637C7B60 
 Media Stream 1 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 28 
  Stream Type : voice-only (0) 
  Negotiated Codec : g711ulaw (160 bytes) 
  Codec Payload Type : 0 
  Negotiated Dtmf-relay : inband-voice 
  Dtmf-relay Payload Type : 0 
  Media Source IP Addr:Port: 172.18.195.49:19444 
  Media Dest IP Addr:Port : 172.18.193.190:16890 
 Media Stream 2 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 33 
  Stream Type : voice+dtmf (1) 
  Negotiated Codec : g711ulaw (160 bytes) 
  Codec Payload Type : 0 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:18928 
  Media Dest IP Addr:Port : 172.18.195.73:18246 
 Media Stream 3 
  State of the stream : STREAM_ACTIVE 
  Stream Call ID : 34 
  Stream Type : dtmf-only (2) 
  Negotiated Codec : No Codec (0 bytes) 
  Codec Payload Type : -1 (None) 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:18428 
  Media Dest IP Addr:Port : 172.16.123.99:34463 
 Media Stream 4 
  State of the stream : STREAM_DEAD 
  Stream Call ID : -1 
  Stream Type : dtmf-only (2) 
  Negotiated Codec : No Codec (0 bytes) 
  Codec Payload Type : -1 (None) 
  Negotiated Dtmf-relay : rtp-nte 
  Dtmf-relay Payload Type : 101 
  Media Source IP Addr:Port: 172.18.195.49:0 
  Media Dest IP Addr:Port : 172.16.123.99:0

 Number of UAC calls: 1

SIP UAS CALL INFO

 Number of UAS calls: 0

Table 1 describes significant fields in this output:

Table 1 show sip-ua calls Field Descriptions 

Field
Description

SIP UAC CALL INFO

Field header that indicates that the following information pertains to the SIP UAC.

Call 1

Field header.

SIP Call ID

UAC call identification number.

State of the call

Indicates the state of the call and is used for debugging purposes. The state is variable and may be different from one Cisco IOS release to another.

Substate of the call

Indicates the substate of the call and is used for debugging purposes. The state is variable and may be different from one Cisco IOS release to another.

Calling Number

Indicates the calling number.

Called Number

Indicates the called number.

Bit Flags

Indicates the bit flags used for debugging.

Source IP Address (Sig)

Indicates the signaling source IP address.

Destn SIP Req Addr: Port:

Indicates the signaling destination Request IP address and port number.

Destn SIP Resp Addr: Port:

Indicates the signaling destination Response IP address and port number.

Destination Name

Indicates the signaling destination host name or IP address.

Number of Media Streams

Indicates the total number of media streams for this UAC call.

Number of Active Streams:

Indicates the total number of active media streams.

RTP Fork Object

Pointer address of internal RTP Fork data structure.

Media Stream

Statistics about each active media stream are reported. The Media Stream header indicates the number of the media stream, and its statistics immediately follow this header.

State of the stream

State of the media stream indicated by the Media Stream header. Can be STREAM_IDLE, STREAM_ADDING, STREAM_DELETING, STREAM_CHANGING, STREAM_ACTIVE, STREAM_DEAD, or Invalid Stream State.

Stream Call ID 

Identification of the stream call indicated by the Media Stream header.

Stream Type 

Type of stream indicated by the Media Stream header. Can be voice-only, DTMF-relay, or voice plus DTMF-relay.

Negotiated Codec

Codec selected for the media stream. Can be G.711, G.729, G.726 or one of their variants.

Codec Payload Type

Payload type of the Negotiated Codec.

Negotiated DTMF-relay
DTMF-relay selected for the media stream indicated by the Media Stream header. Can be inband-voice or rtp-nte.
DTMF-relay Payload Type
Payload type of the negotiated DTMF-relay.
DTMF-relay Payload
DTMF-relay payload used in the media stream indicated by the Media Stream header.

Media Source IP Addr: Port:

The source IP address and port number of the media stream indicated by the Media Stream header.

Media Dest IP Addr: Port:

The destination IP address and port number of the media stream indicated by the Media Stream header.

Number of UAC calls

Final SIP UAC CALL INFO field. Indicates the number of UAC calls.

SIP UAS CALL INFO

Field header that indicates that the following information pertains to the SIP UAS.

Number of UAS calls

Final SIP UAS CALL INFO field. Indicates the number of UAS calls.

Related Commands

Command
Description

debug ccsip all

Enables all SIP-related debugging.

debug ccsip info

Enables tracing of general SIP SPI information.

debug ccsip media

Enables tracing of SIP call media streams.

debug ccsip events

Enables tracing of events that are specific to SIP SPI.


Glossary

3pcc—third-party call controller. In the SIP Support for Media Forking feature, the third-party call controller gateway can signal a call to a gateway on behalf of another gateway.

audio—What the user hears on the telephone. Includes both voice and DTMF digits.

branch—A fork consists of multiple media streams. Each of these streams is referred to as a branch.

call—In SIP, a call consists of all participants in a conference who are invited by a common source. A SIP call is identified by a globally unique call identifier. A point-to-point IP telephony conversation maps into a single SIP call.

CLI—command-line interface.

codec—coder-decoder. Transforms analog signals into a digital bit stream and digital signals back into analog signals. In VoIP applications, it specifies the voice coder rate of speech for a dial peer.

complex forking—A forking scenario in which at least one of the branches is transmitting using a compressed codec and at least one of the other branches is transmitting using a noncompressed (G.711) codec. See also simple forking.

conference—A call in which all parties receive and send media.

dial peer—An addressable call endpoint that contains configuration information including the voice protocol, a codec type, and a telephone number associated with the call endpoint.

DNS—Domain Name System. Used to translate H.323 IDs, URLs, or e-mail IDs to IP addresses. DNS is also used to assist in locating remote gatekeepers and to reverse-map raw IP addresses to host names of administrative domains.

DSP—digital signal processor. DSP modules provide voice compression and packetization services to the VoIP card so that it can be configured and expanded.

DTMF—dual-tone multifrequency. Tones that are generated when a button on a touch-tone phone is pressed. When the tone is generated, it is compressed, transported to the other party, and decompressed.

DTMF-relay— DTMF-relay provides reliable digit relay between VoIP gateways when a low-bandwidth codec is used. DTMF-relay provides a standardized means of transporting DTMF tones in Real-Time Transport Protocol (RTP) packets and is identified by dynamic payload types in the SDP.

dynamic payload—Payloads that are defined at the initiation of a session and that are not assigned to specific RTP formats.

endpoint—A terminal or gateway that acts as a source or sink of voice data. An endpoint can call or be called, and it generates or terminates the information stream.

fork—A fork consists of all the media streams (branches) that are generated and transmitted by an endpoint. Only one party (the controller) receives the media from all of the other parties. The other parties receive media from the controller.

forking—A transmit function of the endpoint. It is used to forward a request in several directions simultaneously; for example to find a user when the user may be at one of several locations.

FQDN—fully qualified domain name. Complete domain name including the host portion; for example, serverA.companyA.com.

FXS—Foreign Exchange Station. An FXS interface connects directly to a standard telephone and supplies ring, voltage, and dial tone.

Invite—A SIP message that initiates a SIP session. It indicates that a user is invited to participate, provides a session description, indicates the type of media, and provides insight regarding the capabilities of the called and calling parties.

IP—Internet protocol. A connectionless protocol that operates at the network layer (Layer 3) of the OSI model. IP provides features for addressing, type-of-service specification, fragmentation and reassembly, and security. IP is defined in RFC 791. This protocol works with TCP and is usually identified as TCP/IP. See also TCP and TCP/IP.

ISDN—Integrated Services Digital Network.

NTE—named telephony event. Format of RTP packets used to transport DTMF digits (or dynamic payload types) as defined in RFC 2833, RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals.

payload types—Define the content and format of RTP packets and the resulting stream of data generated by RTP flow. Payload types are identified in the payload field of the RTP header in each RTP packet. There are two methods for specifying payload types: static and dynamic.

PSTN—public switched telephone network. PSTN refers to the local telephone company.

QoS—quality of service. Measure of performance for a transmission system that reflects its transmission quality and service availability. QoS refers to the ability of a network to provide better service to selected network traffic over various underlying technologies. QoS is not inherent in a network infrastructure. Rather, you must institute QoS by strategically deploying features that implement it throughout the network.

re-Invite—An Invite request sent during an active call leg.

RTCP—Real-Time Control Protocol. Monitors the QoS of an IPv6 RTP connection and conveys information about the ongoing session.

RTP—Real-Time Transport Protocol. A network protocol used to carry packetized audio and video traffic over an IP network.

RTP-NTE—Real Time Protocol-Named Telephony Event. RTP-NTE is described in RFC 2833 and prevents the generation of spurious digits at the receiving gateway. It must be used when DTMF-relay is configured in a forked call.

SDP—Session Description Protocol. Messages that contain capabilities information that are exchanged between gateways.

session—A SIP session includes a set of multimedia senders and receivers and the data streams that flow between the senders and receivers. A SIP multimedia conference is an example of a session. The called party can be invited several times by different calls to the same session.

simple forking—A forking scenario in which all of the branches of the fork use the same voice codec compression. See also complex forking.

simple mixing—A mixer receives multiple streams of the same codec type and combines them into one stream that is sent to the telephony interface.

SIP—Session Initiation Protocol. An application-layer protocol originally developed by the Multiparty Multimedia Session Control (MMUSIC) working group of the Internet Engineering Task Force (IETF). Their goal was to equip platforms to signal the setup of voice and multimedia calls over IP networks. SIP features are compliant with IETF RFC 2543, published in March 1999.

SIP URL—Session Initiation Protocol Uniform Resource Locator. Used in SIP messages to indicate the originator, recipient, and destination of the SIP request. Takes the basic form of user@host, where user is a name or telephone number, and host is a domain name or network address.

speech—Encoded data delivered via the RTP stream. Excludes fax, modem, and DTMF relay. Includes DTMF digits which are sent as inband audio when DTMF relay is not enabled.

SPI—service provider interface. A general category for VoIP protocols.

static payload—Static payloads are assigned to specific RTP formats and are generally grouped for specific applications, for example audio and video conferencing.

streamA fork consists of multiple media streams or branches. Each branch is referred to as a stream.

TCP—Transmission Control Protocol. Connection-oriented transport layer protocol that provides reliable full-duplex data transmissions. TCP is part of the TCP/IP protocol stack. See also TCP/IP and IP.

TCP/IP—Transmission Control Protocol/Internet Protocol. Common name for the suite of protocols developed by the U.S. Department of Defense in the 1970's to support the construction of worldwide internetworks. TCP and IP are the two best known protocols in the suite. See also TCP and IP.

TEL URL—Telephone Uniform Resource Locator. Describes voice call connections to a terminal. Can also be any connection through a voice messaging system or a service that can be operated using DTMF tones. Takes the basic form of tel:telephone-subscriber-number, where tel indicates a URL and requests the local entity to place a voice call, and telephone-subscriber-number is the number to receive the call.

UDP—User Datagram Protocol. Connectionless transport layer protocol in the TCP/IP protocol stack. UDP is a simple protocol that exchanges datagrams without acknowledgments or guaranteed delivery, requiring that error processing and retransmission be handled by other protocols. UDP is defined in RFC 768.

VFC—voice feature card.

voice—A specific type of audio, also referred to as speech.

VoIP—Voice over IP. The ability to carry normal telephone-style voice over an IP-based network.