Table Of Contents

SIP Timer

Contents

Information About SIP Timer

How to Configure SIP Timer

Configuring SIP Timer

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

SIP Timer

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The SIP Timer feature allows the user to configure a number of SIP timers that were hard-coded in the previous releases of Cisco IOS XR software. The ability to configure SIP timers enables users to improve the interoperability and performance of their devices and network environment.

Feature History for SIP Timer Functions

Release	Modification
Release 3.4.1	This feature was introduced on the Cisco XR 12000 Series Router.
Release 3.5.0	No modification.
Release 3.6.0	No modification.

Contents

This module contains the following sections:

•Information About SIP Timer

•How to Configure SIP Timer

•Related Documents

Information About SIP Timer

The SIP timer feature allows the user to configure some of the SIP timers that were hardcoded to default values in the previous releases of Cisco IOS XR software. In the previous releases, the SBC used the default SIP timer values recommended by RFC 3261. See Table 8.

Table 8 Default Values of the Timers 

Timer	Value	Meaning
T1	500 ms default	RTT Estimate
T2	4 s	The maximum retransmit interval for non-INVITE requests and INVITE responses
T4	5 s	Maximum duration a message will remain in the network
Timer A	initially T1	INVITE request retransmit interval, for UDP only
Timer B	64* T1	INVITE transaction timeout timer
Timer C	> 3 min	proxy INVITE transaction timeout
Timer D	> 32 s for UDP 0 s for TCP/SCTP	Wait time for response retransmits
Timer E	initially T1	non-INVITE request retransmit interval, UDP only
Timer F	64* T1	non-INVITE transaction timeout timer
Timer G	initially T1	INVITE response retransmit interval
Timer H	64* T1	Wait time for ACK receipt
Timer I	T4 for UDP 0 s for TCP/SCTP	Wait time for ACK retransmits
Timer J	64* T1 for UDP 0 s for TCP/SCTP	Wait time for non-INVITE request retransmits
Timer K	T4 for UDP 0 s for TCP/SCTP	Wait time for response retransmits

The SBC allows the user to modify T1, T2 and Timer D, using: udp-first-retransmit-interval, udp-max-retransmit-interval and udp-response-linger-period accordingly. Another timer also introduced in this release is invite-timeout parameter, which lets the user choose how long SBC should wait for the remote SIP endpoint to respond to the SBC's outgoing INVITE or Timer B in an outgoing transaction.

In addition to the SIP protocol-level timers, SBC also allows modification of transport-related timers: tcp-connect-timeout (how long TCP SYN will wait for the reply); tcp-idle-timeout (how long TCP connection should stay active while idle), and tls-idle-timeout (how long TLS connection should stay active while idle). Although these timers are transport-level values, IOS-XR supports these timers in SIP only, but not in H.323, nor H.248.

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Note The incorrect configuration of the SIP timer values may lead to unexpected behavior in certain cases.

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How to Configure SIP Timer

This section contains the steps for configuring SIP timers.

Configuring SIP Timer

SUMMARY STEPS

1. configure

2. sbc service-name

3. sbe

4. sip timer

5. tcp-connect-timeout interval

6. tcp-idle-timeout interval

7. tls-idle-timeout interval

8. invite-timeout interval

9. udp-first-retransmit-interval interval

10. udp-max-retransmit-interval interval

11. udp-response-linger-period interval

12. commit

13. exit

14. show services sbc service-name sbe sip timers

DETAILED STEPS

	Command or Action	Purpose
Step 1	configure Example: RP/0/0/CPU0:router# configure	Enables global configuration mode.
Step 2	sbc service-name Example: RP/0/0/CPU0:router(config)# sbc mysbc	Enters the mode of an SBC service. •Use the service-name argument to define the name of the service.
Step 3	sbe Example: RP/0/0/CPU0:router(config-sbc)# sbe	Enters the mode of the signaling border element (SBE) function of the SBC.
Step 4	sip timer Example: RP/0/0/CPU0:router(config-sbc-sbe)# sip timer	Enters the mode of the SIP timer function of the SBC.
Step 5	tcp-connect-timeout interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# tcp-connect-timeout 3000	Configures the time (in milliseconds) that SBC waits for a SIP TCP connection to a remote peer to complete before failing that connection. The default timeout interval is 1000 milliseconds.
Step 6	tcp-idle-timeout interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# tcp-idle-timeout 30000	Minimum time (in milliseconds) a TCP socket has not processed any traffic, before it is closed. The default is 2 minutes. Note The value for this command might not be precise since the idle timers are checked every 12 seconds.
Step 7	tls-idle-timeout interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# tls-idle-timeout 1800000	Minimum time (in milliseconds) a TLS socket can remain idle before it is closed. The default is one hour.
Step 8	invite-timeout interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# invite-timeout 60	Configures the time (in seconds) that SBC waits for a final response to an outbound SIP INVITE request. The default is 180 seconds. If no response is received during that time, an internal "408 Request Timeout" response is generated and returned to the caller.
Step 9	udp-first-retransmit-interval interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# udp-first-retransmit-interval 1000	Configures the time (in milliseconds) that SBC waits for a UDP response or ACK before sending the first retransmission of the relevant signal. If SBC keeps getting no responses, it doubles subsequent retransmission intervals each time until they reach the udp-max-retransmit-interval duration. SBC ceases retransmitting the request and time out the signal if 64 times this duration passes without the receipt of a response/ACK. The default first UDP retransmission interval is 500 milliseconds.
Step 10	udp-max-retransmit-interval interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# udp-max-retransmit-interval 8000	Configures the maximum time interval (in milliseconds) at which SBC will retransmit (see udp-first-retransmit-interval above). The default maximum UDP retransmission interval is 4 seconds.
Step 11	udp-response-linger-period interval Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# udp-response-linger-period 10000	Configures the time (in milliseconds) for which SBC will retain negative UDP responses to INVITE requests. All subsequent retransmitted responses received within this time will be answered with a negative ACK. Thereafter, any further retransmitted responses are ignored. The default UDP response linger period is 32 seconds.
Step 12	commit Example: RP/0/0/CPU0:router(config-sbc-sbe-sip-tmr)# commit	Saves configuration changes. Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.
Step 13	exit Example: RP/0/0/CPU0:router(config-sbc-sbe)# exit	Exits the sip timer mode and returns to the SBE mode.
Step 14	show services sbc service-name sbe sip timers Example: RP/0/0/CPU0:router(config-sbc)# show services sbc mysbc sbe sip timers	Shows the currently configured SIP-related timers.

Additional References

The following sections provide references related to SIP timer support in SBC.

Related Documents

Related Topic	Document Title
Cisco IOS XR master command reference	Cisco IOS XR Master Commands List
Cisco IOS XR SBC interface configuration commands	Cisco IOS XR Session Border Controller Command Reference
Initial system bootup and configuration information for a router using the Cisco IOS XR Software	Cisco IOS XR Getting Started Guide
Cisco IOS XR command modes	Cisco IOS XR Command Mode Reference

Standards

Standards	Title
No new or modified standards are supported by this feature, and support from existing standards has not been modified by this feature.	—

MIBs

MIBs	MIBs Link
—	To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

RFCs

RFCs	Title
RFC 3261	SIP: Session Initiation Protocol
RFC 2543	Session Initiation Protocol

Technical Assistance

Description	Link
The Cisco Technical Support website contains thousands of 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/techsupport