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The Assured Services over Session Initiation Protocol Differentiated Services Code Point (AS SIP—DSCP Policing) Policing and the AS SIP—Media Bandwidth Policing feature adds the media policy functionality to the Cisco Unified Border Element (Cisco UBE) on a per-call basis to control the bandwidth. Real Time Protocol (RTP) packets are dropped, and MIB and system logs are generated if there is any DSCP policy, marking, and media bandwidth profiling violation.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
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You must map RPH to DSCP values to provide priority and precedence for VoIP calls at all layers. DSCP policing and marking are supported as part of the AS SIP—DSCP Policing feature for RTP media. The DSCP policing functionality checks DSCP values for media packets (RTP) and informs incorrect marking of DSCP values. The DSCP marking functionality marks packets with the correct DSCP value as per the SIP RPH.
The AS SIP—DSCP Policing feature supports two new namespaces, UC and CUC. The namespace support is enabled by default and no configuration is required. Asymmetric call leg configuration is also supported: that is, you can have the RPH pass-through configuration on one call leg and RPH to DSCP policing on the another.
In releases prior to Cisco IOS Release 15.2(2)T, Cisco UBE does not support media on a policing per-call basis. Hence, few endpoints negotiate the G729 codec using the SIP offer answer model and send RTP packets with the payload of G711. Few endpoints negotiate with G729 10 ms (one packet per 10 ms) but send two packets as a response to the request of 10 ms. In both cases, more bandwidth than the negotiated bandwidth is used. Cisco UBE has no mechanism to detect bandwidth violation and enforce policing on media policing approaches.
To overcome this problem, the AS SIP—Media Bandwidth Policing feature was introduced in Cisco IOS Release 15.2(2)T. This feature introduces traffic policing on the Cisco UBE to limit media bandwidth usage to the negotiated rate. Excess traffic is dropped when the traffic rate reaches the configured maximum value. The AS SIP—Media Bandwidth Policing feature is supported only on RTP packets.
You can enable system log and Simple Network Management Protocol (SNMP) trap generations to inform system administrators about policing violations.
The request is given an elevated priority to access public switched telephone network (PSTN) gateway resources, such as trunk circuits.
The request can interrupt lower priority requests at a user terminal, such as an IP phone.
The request can carry information from one multilevel priority domain in a telephone network to another, without SIP proxies inspecting or modifying the header field.
In SIP proxies and back-to-back user agents, requests of higher priorities can displace the existing signaling requests or bypass the PSTN gateway capacity limits in effect for lower priorities.
This RPH header provides priority and precedence at Layer 7. It is not treated the same way in lower layers.
DSCP or differentiated services code point (DiffServ) is a computer networking architecture that specifies a simple, scalable, and coarse-grained mechanism for classifying and managing network traffic, and providing quality of service (QoS) on modern IP networks.
Perform this task to configure the AS SIP—DSCP Policing feature at the global level, that is on all dial peers.
1.
enable
2.
configure terminal
3.
voice class dscp-profile
tag
4.
dscp media {audio |
video} {flah-override-override |
flash-override |
flsh |
immediate |
priority |
routine} {dscp-value |
set-af |
set-cf |
ef |
zero}
5.
violation
number
action {disconnect |
ignore} [no-syslog]
6.
end
Perform this task to apply the DSCP policing profile at the global level, that is to apply the profile to all dial peers.
1.
enable
2.
configure terminal
3.
voice service voip
4.
sip
5.
dscp-profile
tag
6.
end
Perform this task to apply the DSCP policing profile at the dial peer level.
When the DSCP policing profile is applied to a dial peer and the mode is configured as RPH pass-through, the policy will be enforced if there is any match for the “r-priority” value in the RPH. If there is no match in the namespace, the domain name system (DNS) will be used to match the “r-priority”.
1.
enable
2.
configure terminal
3.
dial-peer voice
tag {pots |
voatm |
vofr |
voip}
4.
voice-class sip resource priority dscp-profile
tag
5.
end
Perform this task to enable the SNMP trap for the DSCP Policing feature at the global level, that is on all dial peers.
1.
enable
2.
configure terminal
3.
snmp-server enable traps voice [dscp-profile] [fallback] [high-ds0-util] [low-ds0-util] [media-policy]
4.
exit
Perform this task to enable the SNMP trap for the DSCP policing feature for a specific dial peer.
1.
enable
2.
configure terminal
3.
dial-peer voice
tag
voip
4.
snmp enable peer-trap dscp-profile
5.
end
Perform this task to verify the configuration for AS SIP-DSCP Policing feature on Cisco UBE. The show commands need not be entered in any specific order.
1.
enable
2.
show ip interface brief
3.
show call active voice brief
1.
enable
2.
configure terminal
3.
media profile police
tag
4.
violation
number
action {disconnect |
drop |
ignore} [no-syslog]
5.
overhead {audio |
video}
percentage
6.
end
1.
enable
2.
configure terminal
3.
voice service voip
4.
media police-profile
tag
5.
end
Applying the media bandwidth policing profile at the dial peer level involves two actions: applying the profile for a media class and then applying the corresponding media class to a dial peer.
Perform this task to apply the media bandwidth policing profile at the dial peer level.
1.
enable
2.
configure terminal
3.
media class
tag
4.
police profile
tag
5.
exit
6.
dial-peer voice
tag
voip
7.
media-class
tag
8.
end
1.
enable
2.
configure terminal
3.
snmp-server enable traps voice media-policy
4.
exit
1.
enable
2.
configure terminal
3.
dial-peer voice
tag
voip
4.
snmp enable peer-trap media-policy
5.
end
Perform this task to verify the configuration for AS SIP-Media Bandwidth Policing Profile feature on Cisco UBE. The show commands need not be entered in any specific order.
1.
enable
2.
show call history voice brief
3.
show call history voice stats
4.
show call history voice stats
5.
show call history video brief
6.
show call history video stats
7.
show call active voice brief
8.
show call active voice stats
9.
show call active video brief
10.
show call history video stats
11.
show dial-peer voice
The following example shows how to configure the AS SIP—DSCP Policing feature on the Cisco UBE when the incoming invite is an RPH invite:
Router(config)# voice class dscp-profile 1 Router(config-class)# dscp media audio priority 11 Router(config-class)# dscp media audio flsh af11 Router(config)# voice class dscp-profile 2 Router(config-class)# dscp media audio priority 60 Router(config-class)# dscp media audio flash-override af11 Router(config)# voice class dscp-profile 3 Router(config-class)# violation 10 action disconnect Router(config)# voice class dscp-profile 4 Router(config-class)# dscp media audio immediate 2 Router(config-class)# dscp media audio flsh 63 Router(config-class)# dscp media audio flash-override af33 Router(config)# voice class dscp-profile 5 Router(config-class)# dscp media audio immediate 1
The following example shows how to apply DSCP policing globally and at the dial peer level:
![]() Note | The dial peer configuration will have precedence over the global configuration. |
Router(config)# voice service voip Router(conf-voi-serv)# sip Router(conf-serv-sip)# dscp-profile 2 Router(config)# dial-peer voice 1 voip Router(config-dial-peer)# session protocol sipv2 Router(config-dial-peer)# voice-class sip resource priority dscp-profile 1
Router(config)# media profile police 1 Router(cfg-mediaprofile)# violation 20000 action disconnect no-syslog Router(cfg-mediaprofile)# overhead audio 15
The following example shows how to apply the media bandwidth policing profile globally and at the dial peer level:
Router(config)# voice service voip Router(conf-voi-serv)# media police-profile 1 Router(config)# media class 1 Router(cfg-mediaclass)# police profile 1 Router(cfg-mediaclass)# end Router# configure terminal Router(config)# dial-peer voice 4 voip Router(config-dial-peer)# media-class 1
Related Topic |
Document Title |
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Cisco IOS commands |
|
Cisco IOS voice commands |
|
Modular quality of service CLI overview |
Description |
Link |
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The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.