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This document describes the Configurable Timers in H.225 feature that was introduced in Cisco IOS Release 12.1(2)T. This document contains the following sections:
The Configurable Timers in H.225 feature allows users to configure the H.225 TCP connection timeout value for all out-going call attempts (on a per VoIP dial-peer basis).
In previous releases of the Cisco IOS software, the call attempt timeout was 15 seconds and could not be changed. In some cases, however, users might need a shorter timeout value to facilitate a faster fail-over. In other cases, users might need a greater timeout value.
The Configurable Timers in H.225 feature addresses those needs by allowing the user to override the default of 15 seconds and configure the timeout value.
The Configurable Timers in H.225 feature is limited to H.323 dial-peers.
The Configurable Timers in H.225 feature is supported on any existing IOS voice platforms, including the following:
Standards
No new or modified standards are supported by this feature.
MIBs
No new or modified MIBs are supported by this feature.
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO.
RFCs
No new or modified RFCs are supported by this feature.
The Configurable Timers in H.225 feature requires the Cisco H.323 VoIP Gateway for Cisco Access Platforms feature.
To use the Configurable Timers in H.225 feature, you must first create an H.323 voice class and then specify the timeout value associated with that class. To configure the H.225 TCP timeout value, do the following:
| Command | Purpose | |
|---|---|---|
Step 1 | Router# config term | Enter configuration mode. |
Step 2 | Router(config)# voice class h323 number | Enters voice class mode to create or modify an H.323 voice class. The number argument identifies the H.323 voice class. |
Step 3 | Router(config-class)# h225 timeout tcp establish value | Set the H.225 TCP timeout value for the specified voice class. The value argument indicates the timeout value in seconds. |
Step 4 | Router(config-class)# exit | Exits voice class mode. |
Next, you must associate the H.323 voice class with each VoIP dial peer that should use the specified timeout. To associate the H.323 voice class with a dial peer, do the following:
| Command | Purpose | |
|---|---|---|
Step 1 | Router# config term | Enter configuration mode. |
Step 2 | Router(config)# dial-peer voice number voip | Enters dial-peer configuration mode and defines a remote VoIP dial peer. The number argument is one or more digits identifying the dial peer. The voip keyword indicates a VoIP peer using voice encapsulation on the IP network. |
Step 3 | Router(config-dialpeer)# voice-class h323 number | Associates the specified H.323 voice class (and all of its related attributes) with the dial peer. The number argument identifies the H.323 voice class. |
To verify the timeout value are defined for a dial peer, enter the show run command. The output shows the current configuration of the voice class and the dial peer.
router# show run
Building configuration...
Current configuration:
!
.
.
.
voice class h323 1
h225 timeout tcp etablish 10
dial-peer voice 919 voip
application session
destination-pattern 919555....
voice-class codec 1
voice-class h323 1
session target ras
.
.
.
In the following example,a timeout value of 10 is configured for the H.323 voice class labled 3. Voice class 3 is then associated with the dial-peer identified as 919. This sets the H.225 TCP timeout for dial-peer 919 to 10.
voice class h323 1
h225 timeout tcp etablish <value 0 to 30 seconds>
dial-peer voice 919 voip
application session
destination-pattern 919555....
voice-class codec 1
voice-class h323 1
session target ras
This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
To create an H.323 voice class that is independent of a dial peer and can be used on multiple dial peers, use the voice class h323 command. To remove the voice class, use the no form of the command.
voice class h323 number
Syntax Description
number Specify a number to identify the voice class.
Defaults
There are no default behaviors or values for this command.
Command Modes
Global configuration
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
None
Examples
The following example creates an H.323 voice class labeled 1:
voice class h323 1
Related Commands
| Command | Description |
|---|---|
h225 timeout tcp establish | Subcommand that configures the H.225 TCP timeout. |
To set the H.225 TCP timeout value for VoIP dial peers, use the h225 timeout tcp establish subcommand. To set the timeout back to its default, use the no form of the command.
h225 timeout tcp establish value
Syntax Description
value Specify the number of seconds for the timeout. Possible values are 0 to 30. The default is 15. If you specify 0, the H.225 TCP timer is disabled.
Defaults
The default is 15 seconds.
Command Modes
Voice class configuration
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
None
Examples
The following example configures a timeout of 10 seconds, which is associated with the H.323 voice class labeled 1:
voice class h323 1 h225 timeout tcp establish 10
Related Commands
| Command | Description |
|---|---|
voice class h323 | Command that establishes an H.323 voice class. |
gatekeeper---A gatekeeper maintains a registry of devices in the multimedia network. The devices register with the gatekeeper at startup, and request admission to a call from the gatekeeper.
The gatekeeper is an H.323 entity on the LAN that provides address translation and control access to the LAN for H.323 terminals and gateways. The gatekeeper may provide other services to the H.323 terminals and gateways, such as bandwidth management and locating gateways.
gateway---A gateway allows H.323 terminals to communicate with non-H.323 terminals by converting protocols. A gateway is the point at which a circuit-switched call is encoded and repackaged into IP packets.
A H.323 gateway is an endpoint on the LAN that provides real-time, two-way communications between H.323 terminals on the LAN and other ITU-T terminals in the WAN, or to another H.323 gateway.
H.323---An International Telecommunication Union (ITU-T) standard that describes packet-based video, audio, and data conferencing. H.323 is an umbrella standard that describes the architecture of the conferencing system, and refers to a set of other standards (H.245, H.225.0, and Q.931) to describe its actual protocol.
RAS---Registration, admission, and status protocol. This is the protocol that is used between endpoints and the gatekeeper to perform management functions. The RAS signaling function performs registration, admissions, bandwidth changes, status, and disengage procedures between the VoIP gateway and the gatekeeper.
RTP---Real-time transport protocol. One of the IPv6 protocols. RTP is designed to provide end-to-end network transport functions for applications transmitting real-time data, such as audio, video, or simulation data, over multicast or unicast network services. RTP provides services such as payload type identification, sequence numbering, timestamping, and delivery monitoring to real-time applications.
VoIP---Voice over IP. The ability to carry normal telephone-style voice over an IP-based Internet with POTS-like functionality, reliability, and voice quality. VoIP is a blanket term which generally refers to Cisco's standards-based (H.323, etc.) approach to IP voice traffic.
Posted: Wed May 31 08:47:07 PDT 2000
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