Configuring Header Compression Using IPHC Profiles

Last Updated: December 5, 2011

Header compression is a mechanism that compresses the IP header in a packet before the packet is transmitted. Header compression reduces network overhead and speeds up the transmission of either Real-Time Transport Protocol (RTP) or Transmission Control Protocol (TCP) packets.

One method of configuring header compression on your network is to use an IP header compression (IPHC) profile. An IPHC profile is a kind of template within which you can configure the type of header compression that you want to use, set all of the optional features and parameters for header compression, and then apply the profile to an interface, subinterface, or Frame Relay permanent virtual circuit (PVC).

This module describes the concepts and tasks for configuring header compression using IPHC profiles.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for Using IPHC Profiles

Before using IPHC profiles to configure header compression, read the information in the "Header Compression" module.

Restrictions for Using IPHC Profiles

IPHC profiles are not supported on L2TP networks.

Information About Using IPHC Profiles

Benefits of Using IPHC Profiles

An IPHC profile provides a flexible means of enabling header compression and the options associated with header compression. For example, header compression (and the header compression options) can be enabled once in an IPHC profile, and then the IPHC profile can be applied to one or more of the following:

  • An interface
  • A subinterface
  • A Frame Relay PVC

IPHC Profile Types

You use the iphc-profile command to create the IPHC profile. When you create an IPHC profile, you must specify the IPHC profile type. The IPHC profile choices are Internet Engineering Task Force (IETF) or van-jacobson. You specify the IPHC profile type with the ietf keyword or the van-jacobson keyword of the iphc-profile command.

The ietf profile type conforms with and supports the standards established with RFC 2507, RFC 2508, RFC 3544, and RFC 3545 and is typically associated with non-TCP header compression (for example, RTP header compression). The van-jacobson profile type conforms with and supports the standards established with RFC 1144 and is typically associated with TCP header compression.

Considerations When Specifying the IPHC Profile Type

When specifying the IPHC profile type, consider whether you are compressing TCP traffic or non-TCP (that is, RTP) traffic. Also consider the header compression format capabilities of the remote network link to which you will be sending traffic.

The IPHC profile type that you specify directly affects the header compression format used on the remote network links to which the IPHC profile is applied. Only TCP traffic is compressed on remote network links using a van-jacobson IPHC profile, whereas both TCP and non-TCP (for example, RTP) traffic is compressed on remote network links using an ietf IPHC profile.


Note
The header compression format in use on the router that you are configuring and the header compression format in use on the remote network link must match.

Configurable Header Compression Features and Settings

The specific header compression features and settings that you can configure (that is, enable or modify) are determined by the IPHC profile type that you select (either van-jacobson or ietf) when you create the IPHC profile. There is one set of features and options for the van-jacobson IPHC profile type and another set for the ietf IPHC profile type. Both sets are listed below.

Features and Settings for van-jacobson IPHC Profile Type Header Compression

If you specify van-jacobson as the IPHC profile type, you can enable TCP header compression and set the number of TCP contexts. The table below lists the van-jacobson IPHC profile type header compression features and settings that are available and the command used to enable that feature or setting.

Table 1 van-jacobson IPHC Profile Type Header Compression Features and Settings

Feature or Setting

Command

TCP header compression

tcp

Number of contexts available for TCP header compression

tcp contexts

Features and Settings for ietf IPHC Profile Type Header Compression

If you specify ietf as the IPHC profile type, you can enable non-TCP header compression (that is, RTP header compression), along with a number of additional features and settings. The table below lists the ietf IPHC profile type header compression features and settings that are available and the command used to enable that feature or setting.

Table 2 ietf IPHC Profile Type Header Compression Features and Settings

Feature or Setting

Command

Non-TCP header compression

non-tcp

Number of contexts available for non-TCP header compression

non-tcp contexts

RTP header compression

rtp

Enhanced Compressed Real-Time Transport Protocol (ECRTP) on an interface

recoverable-loss

Context refresh (full-header refresh) options, such as the amount of time to wait before a full-header is refreshed

refresh max-time refresh max-period refresh rtp

Context-status feedback messages from the interface or link

feedback

Maximum size of the compressed IP header

maximum header

TCP header compression

tcp

Number of contexts available for TCP header compression

tcp contexts

Tasks for Using IPHC Profiles

The tasks for configuring header compression using an IPHC profile are described below.

  1. Create the IPHC profile and specify the IPHC profile type (ietf or van-jacobson) that you want to use.
  2. Enable or set the header compression features available for the IPHC profile type that you specified when you created the IPHC profile. The header compression features vary by IPHC profile type.
  3. Attach the IPHC profile to an interface, subinterface, or Frame Relay PVC.
  4. Display information about the IPHC profiles that you have created.

The figure below illustrates the high-level processes for configuring header compression using IPHC profiles.

Figure 1 Flowchart for Configuring Header Compression Using IPHC Profiles


How to Configure Header Compression Using IPHC Profiles

Creating an IPHC Profile

The first task is to create an IPHC profile. When you create an IPHC profile, you can create either an ietf IPHC profile or a van-jacobson IPHC profile, by using the corresponding keyword of the iphc-profile command.

To create either an ietf IPHC profile or a van-jacobson IPHC profile, complete the following steps.

Before You Begin

Before completing the steps listed below, determine the type of IPHC profile that you want to create: ietf or van-jacobson. The IPHC profile type that you create directly affects the header compression options available for you.

For more information about IPHC profile types and considerations for selecting one or the other, see the IPHC Profile Types.


Note

The IPHC profile name must be unique and cannot be longer than 32 characters. IPHC profile names exceeding this maximum are truncated to 32 characters.

>

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    iphc-profile profile-name {ietf | van-jacobson}

4.    end


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
iphc-profile profile-name {ietf | van-jacobson}


Example:

Router(config)# iphc-profile profile2 ietf

 

Creates an IPHC profile and enters IPHC-profile configuration mode.

  • Enter the IPHC profile name and the IPHC profile type keyword.
 
Step 4
end


Example:

Router(config-iphcp)# end

 

(Optional) Exits IPHC-profile configuration mode.

 

What to Do Next

So far you have created either an ietf IPHC profile or a van-jacobson IPHC profile.

The next step is to enable or set any additional header compression features or options available for the type of IPHC profile that you created.

Choose one of the following:

Enabling the Options for van-jacobson IPHC Profile Type Header Compression

If you created a van-jacobson IPHC profile, you can enable TCP header compression and set the number of TCP contexts.


Note
If you created an ietf IPHC profile, the header compression options available to you are documented in the Enabling the Options for ietf IPHC Profile Type Header Compression.

To enable TCP header compression set the number of TCP contexts, complete the following steps.

Before You Begin

The IPHC profile must exist.


SUMMARY STEPS

1.    enable

2.    configure terminal

3.    iphc-profile profile-name

4.    tcp

5.    tcp contexts {absolute number-of-contexts | kbps-per-context kbps}

6.    end


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
iphc-profile profile-name


Example:

Router(config)# iphc-profile profile2

 

Specifies the IPHC profile and enters IPHC-profile configuration mode.

  • Enter the IPHC profile name.
 
Step 4
tcp


Example:

Router(config-iphcp)# tcp

 

(Optional) Enables TCP header compression.

 
Step 5
tcp contexts {absolute number-of-contexts | kbps-per-context kbps}


Example:

Router(config-iphcp)# tcp contexts absolute 25

 

(Optional) Sets the number of TCP contexts.

  • Enter either the absolute keyword and the fixed number or the kbps-per-context keyword and the number of kbps to allow for each context.
 
Step 6
end


Example:

Router(config-iphcp)# end

 

(Optional) Exits IPHC-profile configuration mode.

 

What to Do Next

The next step is to attach the IPHC profile to an interface, a subinterface, or a Frame Relay PVC. For the instructions to follow, see the Attaching the IPHC Profile.

Enabling the Options for ietf IPHC Profile Type Header Compression


Note
If you created a van-jacobson IPHC profile, complete the tasks in the Enabling the Options for van-jacobson IPHC Profile Type Header Compression.

If you created an ietf IPHC profile, you can enable or set a variety of header compression options. These options include enabling non-TCP header compression, enabling RTP header compression, and enabling ECRTP. For a list of the additional header compression features or settings available with an ietf IPHC profile, see the Enabling the Options for ietf IPHC Profile Type Header Compression.

Before You Begin

The IPHC profile must exist.


SUMMARY STEPS

1.    enable

2.    configure terminal

3.    iphc-profile profile-name

4.    non-tcp

5.    non-tcp contexts {absolute number-of-contexts | kbps-per-context kbps }

6.    rtp

7.    recoverable-loss {dynamic | packet-drops}

8.    refresh max-period {number-of-packets | infinite}

9.    refresh max-time {length-of-time | infinite}

10.    refresh rtp

11.    feedback

12.    maximum header max-header-size

13.    tcp

14.    Router(config-iphcp)# tcp contexts absolute 75

15.    end


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
iphc-profile profile-name


Example:

Router(config)# iphc-profile profile3

 

Specifies the IPHC profile and enters IPHC-profile configuration mode.

  • Enter the IPHC profile name.
 
Step 4
non-tcp


Example:

Router(config-iphcp)# non-tcp

 

(Optional) Enables non-TCP header compression.

 
Step 5
non-tcp contexts {absolute number-of-contexts | kbps-per-context kbps }


Example:

Router(config-iphcp)# non-tcp contexts absolute 75

 

(Optional) Sets the number of contexts available for non-TCP header compression.

  • Enter either the absolute keyword and the fixed number or the kbps-per-context keyword and the number of kbps to allow for each context.
 
Step 6
rtp


Example:

Router(config-iphcp)# rtp

 

(Optional) Enables RTP header compression.

Note    This command automatically enables non-TCP header compression.
 
Step 7
recoverable-loss {dynamic | packet-drops}


Example:

Router(config-iphcp)# recoverable-loss 5

 

(Optional) Enables ECRTP.

 
Step 8
refresh max-period {number-of-packets | infinite}


Example:

Router(config-iphcp)# refresh max-period 700

 

(Optional) Sets the number of packets sent between full-header refresh occurrences.

  • Enter the number of packets sent between full-header refresh occurrences, or enter the infinite keyword to indicate no limitation on the number of packets sent between full-header refresh occurrences.
Note    Non-TCP header compression must be enabled first.
 
Step 9
refresh max-time {length-of-time | infinite}


Example:

Router(config-iphcp)# refresh max-time infinite

 

(Optional) Sets the amount of time to wait before a full-header refresh occurrence.

  • Enter the length of time, in seconds, to wait before a full-header refresh occurrence, or enter the infinite keyword to indicate no limitation on the time between full-header refreshes.
Note    Non-TCP header compression must be enabled first.
 
Step 10
refresh rtp


Example:

Router(config-iphcp)# refresh rtp

 

(Optional) Enables a context refresh for RTP header compression.

Note    RTP header compression must be enabled first.
 
Step 11
feedback


Example:

Router(config-iphcp)# feedback

 

(Optional) Disables the context-status feedback messages from the interface or link.

Note    TCP or non-TCP header compression must be enabled first.
 
Step 12
maximum header max-header-size


Example:

Router(config-iphcp)# maximum header 75

 

(Optional) Specifies the maximum size of the compressed IP header.

  • Enter the maximum size of the compressed IP header, in bytes.
Note    TCP or non-TCP header compression must be enabled first.
 
Step 13
tcp


Example:

Router(config-iphcp)# tcp

 

(Optional) Enables TCP header compression.

 
Step 14
Router(config-iphcp)# tcp contexts absolute 75  

(Optional) Sets the number of contexts available for TCP header compression.

  • Enter either the absolute keyword and the fixed number or the kbps-per-context keyword and the number of kbps to allow for each context.
 
Step 15
end


Example:

Router(config-iphcp)# end

 

(Optional) Exits IPHC-profile configuration mode.

 

Attaching the IPHC Profile

You can attach the IPHC profile (either an ietf IPHC profile or a van-jacobson IPHC profile) to an interface, a subinterface, or a Frame Relay PVC.

Choose one of the following:

Attaching an IPHC Profile to an Interface

To attach an IPHC profile to an interface or subinterface, complete the following steps.

Before You Begin
  • The IPHC profile must exist.
  • IP must be enabled on the interface or subinterface.
  • The type of encapsulation in use on the interface or subinterface must support header compression. Two types of encapsulation that typically support header compression are PPP and HDLC encapsulation.
  • Header compression must not already be enabled.
  • The interface or subinterface must have sufficient memory.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number [name-tag]

4.    iphc-profile profile-name

5.    end


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
interface type number [name-tag]


Example:

Router(config)# interface fastethernet0

 

Configures an interface type and enters interface configuration mode.

  • Enter the interface type and the interface number.
 
Step 4
iphc-profile profile-name


Example:

Router(config-if)# iphc-profile profile1

 

Attaches the IPHC profile to the interface.

  • Enter the IPHC profile to be attached to the interface specified in Step 3 .
 
Step 5
end


Example:

Router(config-if)# end

 

(Optional) Exits IPHC-profile configuration mode.

 

Attaching an IPHC Profile to a Frame Relay PVC

To attach an IPHC profile to a Frame Relay PVC, complete the following steps.

Before You Begin
  • The IPHC profile must exist.
  • On a network that is using Frame Relay encapsulation, IPHC profiles are supported only in the Frame Relay map-class infrastructure.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    map-class frame-relay map-class-name

4.    frame-relay iphc-profile profile-name

5.    exit

6.    interface type number [name-tag]

7.    encapsulation frame-relay

8.    ip address ip-address mask

9.    frame-relay interface-dlci dlci

10.    class name

11.    end


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
map-class frame-relay map-class-name


Example:

Router(config)# map-class frame-relay mapclass1

 

Creates a map class and enters static map class configuration mode.

  • Enter the Frame Relay map class name.
 
Step 4
frame-relay iphc-profile profile-name


Example:

Router(config-map-class)# frame-relay iphc-profile profile2

 

Attaches the IPHC profile to the Frame Relay map class.

  • Enter the IPHC profile to be attached to the Frame Relay map class created in Step 3 .
 
Step 5
exit


Example:

Router(config-map-class)# exit

 

Exits static map class configuration mode.

 
Step 6
interface type number [name-tag]


Example:

Router(config)# interface serial2/0

 

Configures an interface type and enters interface configuration mode.

  • Enter the interface type and the interface number.
 
Step 7
encapsulation frame-relay


Example:

Router(config-if)# encapsulation frame-relay

 

Enables Frame Relay encapsulation on the interface.

 
Step 8
ip address ip-address mask


Example:

Router(config-if)# ip address 209.165.200.225 255.255.255.224

 

Sets a primary IP address for an interface.

  • Enter the IP address and mask for the associated IP subnet.
 
Step 9
frame-relay interface-dlci dlci


Example:

Router(config-if)# frame-relay interface-dlci 100

 

Assigns a data-link connection identifier (DLCI) to a specified Frame Relay interface on the router or access server and enters Frame Relay DLCI configuration mode.

  • Enter the DLCI number to be used on the specified interface.
 
Step 10
class name


Example:

Router(config-fr-dlci)# class mapclass1

 

Associates a map class with a specified DLCI.

  • Enter the name of the map class to associate with the specified DLCI.
 
Step 11
end


Example:

Router(config-fr-dlci)# end

 

(Optional) Exits Frame Relay DLCI configuration mode.

 

Displaying the IPHC Profile Statistics

In this task, you can display statistical information about the IPHC profiles that you have created and configured. Displaying the IPHC profile statistics allows you to confirm that the IPHC profile is configured as you intended.

Information reported includes the IPHC profile name and profile type, the type of header compression enabled, whether any optional header compression features (such as the number of contexts) are enabled, and the name of the interface to which the IPHC profile is attached (if applicable).

To display the IPHC profile statistics, complete the following steps.

Before You Begin

The IPHC profile must exist.


SUMMARY STEPS

1.    enable

2.    show iphc-profile [profile-name]

3.    end


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
show iphc-profile [profile-name]


Example:

Router# show iphc-profile profile1

 

Displays configuration information for one or more IPHC profiles.

  • (Optional) Enter the name of the IPHC profile you want to display. If you do not specify an IPHC profile name, all IPHC profiles are displayed.
 
Step 3
end


Example:

Router# end

 

(Optional) Exits privileged EXEC mode.

 

Configuration Examples for Using IPHC Profiles

Example Creating an IPHC Profile

In the following example, a van-jacobson IPHC profile called profile1 has been created.

Router> enable
Router# configure terminal
Router(config)# iphc-profile profile1 van-jacobson
Router(config-iphcp)# end
 
       
 In the following example, an ietf IPHC profile called profile2 has been created. 
 
       
Router> enable
 
       
Router# configure terminal
 
       
Router(config)# iphc-profile profile2 ietf
 
       
Router(config-iphcp)# end
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Example Enabling TCP Header Compression
 
     
 
      
 
        
         
       
 In the following example, TCP header compression has been enabled in a van-jacobson IPHC profile called profile1. Additionally, the number of TCP contexts has been set to 25.
 
       
Router> enable
 
       
Router# configure terminal
 
       
Router(config)# iphc-profile profile1
 
       
Router(config-iphcp)# tcp
 
       
Router(config-iphcp)# tcp contexts absolute 25
 
       
Router(config-iphcp)# end
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Example Enabling Non-TCP Header Compression
 
     
 
      
 
        
         
       
 In the following example, RTP header compression has been enabled in an ietf IPHC profile called profile2. Additionally, ECRTP has been enabled with the recoverable-loss command, and the size of the compressed IP header has been set to 75 bytes.
 
       
Router> enable
 
       
Router# configure terminal
 
       
Router(config)# iphc-profile profile2
 
       
Router(config-iphcp)# rtp
 
       
Router(config-iphcp)# recoverable-loss 5
 
       
Router(config-iphcp)# maximum header 75
 
       
Router(config-iphcp)# end
 
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Example Attaching the IPHC Profile
 
     
 
      
 
        
         
       
 In the following example, an IPHC profile called profile1 is attached to serial interface 0.
 
       
Router> enable
 
       
Router# configure terminal
 
       
Router(config)# interface serial0
 
       
Router(config-if)# iphc-profile profile1
 
       
Router(config-if)# end
 
       
 
       
 In the following example, an IPHC profile called profile2 is attached to a Frame Relay map class called mapclass1.
 
       
Router> enable
 
       
Router# configure terminal
 
       
Router(config)# map-class frame-relay mapclass1
 
       
Router(config-map-class)# frame-relay iphc-profile profile2
 
       
Router(config-map-class)# exit
 
       
Router(config)# interface serial2/0
 
       
Router(config-if)# encapsulation frame-relay
 
       
Router(config-if)# ip address 209.165.200.225 255.255.255.224
 
       
Router(config-if)# frame-relay interface-dlci 100
 
       
Router(config-fr-dlci)# class mapclass1
 
       
Router(config-fr-dlci)# end
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Example Reporting IPHC Profile Statistics
 
     
 
      
 
        
         
       
 The following is sample output from the show iphc-profile command. In this output, information about two IPHC profiles, profile21 and 20, is displayed. 
 
       
Router# show iphc-profile
IPHC Profile "profile21"
Type: VJ
  Compressing: TCP 
  Contexts   : TCP fixed at 150 
  Controlled interfaces: (1)
    Se3/1
IPHC Profile "profile20"
Type: IETF
  Compressing: TCP NON-TCP (RTP)
  Contexts   : TCP 1 for each 0 kbits NON-TCP 1 for each 0 kbits 
  Refresh    : NON-TCP and RTP every 5 seconds or 256 packets
  Controlled interfaces: (1)
    Se3/0
 
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
   
 
   
 
     
      
    
Additional References
 
    
 
     
 
       
        
      
 The following sections provide references related to IPHC profiles. 
 
     
 
     
 
       
        
      
Related Documents
 
      
 
        
         
       
 
         
         
 
           
 Related Topic 
 		 
           
 Document Title 
 		 
         
 
         
         
         
 
           
 Cisco IOS commands 
 		 
           
 Cisco IOS Master Commands List, All Releases 
 		 
         
 
         
 
           
 QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples 
 		 
           
 Cisco IOS Quality of Service Solutions Command Reference 
 		 
         
 
         
 
           
 QoS functionality overview 
 		 
           
 "Quality of Service Overview" module 
 		 
         
 
         
 
           
 Header compression overview 
 		 
           
 "Header Compression" module 
 		 
         
 
         
 
           
 RTP header compression 
 		 
           
 "Configuring RTP Header Compression" module 
 		 
         
 
         
 
           
 TCP header compression 
 		 
           
 "Configuring TCP Header Compression" module 
 		 
         
 
         
 
           
 Class-based RTP and TCP header compression 
 		 
           
 "Configuring Class-Based RTP and TCP Header Compression" module 
 		 
         
 
         
       
 
      
 
     
 
     
 
       
        
      
Standards
 
      
 
        
         
       
 
         
         
 
           
 Standard 
 		 
           
 Title 
 		 
         
 
         
         
         
 
           
 No new or modified standards are supported, and support for existing standards has not been modified. 
 		 
           
 -- 
 		 
         
 
         
       
 
      
 
     
 
     
 
       
        
      
MIBs
 
      
 
        
         
       
 
         
         
 
           
 MIB 
 		 
           
 MIBs Link 
 		 
         
 
         
         
         
 
           
 No new or modified MIBs are supported, and support for existing MIBs has not been modified. 
 		 
           
 To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: 
 
 http://www.cisco.com/go/mibs 
 		 
         
 
         
       
 
      
 
     
 
     
 
       
        
      
RFCs
 
      
 
        
         
       
 
         
         
 
           
 RFC 
 		 
           
 Title 
 		 
         
 
         
         
         
 
           
 RFC 1144 
 		 
           
 Compressing TCP/IP Headers for Low-Speed Serial Links 
 		 
         
 
         
 
           
 RFC 2507 
 		 
           
 IP Header Compression 
 		 
         
 
         
 
           
 RFC 2508 
 		 
           
 Compressing IP/UDP/RTP Headers for Low-Speed Serial Links 
 		 
         
 
         
 
           
 RFC 3544 
 		 
           
 IP Header Compression over PPP 
 		 
         
 
         
 
           
 RFC 3545 
 		 
           
 Enhanced Compressed RTP (CRTP) for Links with High Delay, Packet Loss and Reordering 
 		 
         
 
         
       
 
      
 
     
 
     
 
       
        
      
Technical Assistance
 
      
 
        
         
       
 
         
         
 
           
 Description 
 		 
           
 Link 
 		 
         
 
         
         
         
 
           
 The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. 
 		 
           
 http://www.cisco.com/cisco/web/support/index.html 
 		 
         
 
         
       
 
      
 
     
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
Feature Information for Configuring Header Compression Using IPHC Profiles
 
    
 
     
 
       
        
      
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 www.cisco.com/go/cfn. An account on Cisco.com is not required. 
 
     
 
     
 
       
        
      
 
        
         
       
 
         
         
 
          Table 3 
          Feature Information for Configuring Header Compression Using IPHC Profiles 
         
 
         
       
 
       
 
         
         
 
           
 Feature Name 
 		 
           
 Releases 
 		 
           
 Feature Information 
 		 
         
 
         
         
         
 
           
 IPHC Profiles 
 
 
 		 
           
 12.4(9)T 
 
 
 		 
           
 The IPHC Profiles feature allows you to configure header compression in a kind of template ("profile") and to apply the profile to interfaces, subinterfaces, or Frame Relay PVCs. 
 
 The following commands were introduced by this feature: feedback, iphc-profile, maximum header, non-tcp, non-tcp contexts, recoverable-loss, refresh max-period, refresh max-time, refresh rtp, rtp, show iphc-profile, tcp, tcp contexts. 
 		 
         
 
         
       
 
      
 
     
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
 
 
    
 
     
 
       
        
      
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