WarmTransfer
sip media · published

SIP session timers

Verified 2026-09-25 · 56 sources · tier 1–3 · 2 disputed

Also known as Min-SE, RFC 4028 session timers, Session-Expires, session refresh.

Disputed: 2 sources below carry conflicting evidence.

SIP session timers provide a mechanism to keep SIP dialogs alive and detect dead sessions across intermediaries 56. The protocol defines signaling headers and timer intervals that allow user agents or proxies to periodically refresh active calls 42​32.

Protocol mechanics and negotiation

RFC 4028 recommends a Session-Expires value of 1800 seconds (30 minutes) 42. The RFC establishes an absolute minimum session interval of 90 seconds, reasoned as slightly more than twice the maximum duration of a timed-out SIP transaction 41. When present in a request or response, the Min-SE header value must not be lower than 90 seconds 28. If the Min-SE header is absent, its value defaults to 90 seconds 27. The letter x is reserved as the compact form of the Session-Expires header 13.

The session timer extension operates even when only one user agent in the dialog supports it 56. RFC 4028 states that sending Require: timer or Proxy-Require: timer in a UAC request is NOT RECOMMENDED 39. The refresher parameter in the Session-Expires header accepts either uac or uas to specify which entity performs session refreshes 37. When the UAC supports session timers but specifies no refresher preference, the UAS decides whether it or the UAC acts as the refresher 51. If the UAC does not provide Supported: timer, the UAS must assign the refresher role to uas 50. A UAS may lower the Session-Expires value in its response, provided it does not reduce it below the Min-SE value received in the request 52. If only the UAC requested a session timer and the returned 2xx response contains no Session-Expires header, the UAC performs refreshes using its requested value and assumes refresher=uac 49.

A proxy may insert a Session-Expires header into a request that lacks one before forwarding it 32. A proxy may reduce Session-Expires but cannot drop it below Min-SE; it should increase Min-SE when needed but must not lower it 33. If a UAS or proxy receives a Session-Expires value lower than its configured minimum, it returns a 422 Session Interval Too Small response 3. A 422 response must include a Min-SE header 2. Following a 422, the UAC retries using a Min-SE equal to the largest Min-SE returned across all 422 responses for that request 4.

Refresh methods and session teardown

RFC 4028 recommends that the designated refresher transmit the refresh request once half of the negotiated session interval has passed 34. Any refresh request sent within an active session timer dialog should include the Session-Expires header 35. RFC 4028 recommends using UPDATE over re-INVITE for refreshes if the UAC knows its peer supports UPDATE 54. RFC 3311 UPDATE lets a UA change session parameters such as media without changing dialog state, including before the initial INVITE completes 53. Support for UPDATE is advertised by listing UPDATE in the Allow header of the INVITE and within reliable provisional or final responses 5. Conversely, RFC 3311 recommends re-INVITE instead of UPDATE for session modifications on confirmed dialogs because UPDATE requires an immediate response 1. WarmTransfer's reading of the sources is that RFC 4028's preference for UPDATE refreshes and RFC 3311's preference for re-INVITE on confirmed dialogs address distinct scenarios—specifically, content-free session refreshes versus user-visible session modifications—rather than conflicting with one another 55.

If a re-INVITE is selected to perform a refresh, it should include an SDP offer even if parameters remain unchanged, indicating the lack of change by reusing the earlier origin field values 38. If a session refresh transaction experiences a timeout or receives a 408 or 481 response, the UAC terminates the session by sending a BYE 36. If no refresh is received, the non-refresher should send a BYE shortly before expiration; the recommended margin is the lesser of 32 seconds and one third of the total interval 12. WarmTransfer's reading of the sources is that with an 1800-second Session-Expires interval and absent refreshes, a non-refresher following RFC 4028 terminates the call roughly 32 seconds prior to the 30-minute threshold, meaning drops clustered just under 30 minutes indicate session timer issues 26.

Platform implementations and behaviors

Platform Session-Expires default / range Min-SE default / range Refresher behavior
Cisco CUBE 1800 s (CUCM default) 22 1800 s / 90–86400 s 15​17 not covered by the sources below
AudioCodes Mediant SBC 180 s / 90–86400 s 11 0 s / 0–1000000 s 9 SBCSessionRefreshingPolicy: 0 (Remote Refresher, default), 1 (SBC Refresher) 10
Oracle SBC 1800 s / starts at 64 s 31 90 s / starts at 64 s 31 Defaults: request-refresher uac, response-refresher uas, force-reinvite disabled 30
Asterisk res_pjsip 1800 s 6 90 s 6 Configured via timers (defaults to yes; takes no, yes, required, always, forced) 7

Cisco CUBE, CUCM, and CVP

This is disputed: while one source states that the session refresh command under voice service voip sip on CUBE adds a Session-Expires header to an outbound INVITE when the inbound leg lacked one 20, the CUBE configuration guide states that Cisco SIP gateways cannot initiate session timers, though they support them when requested by another UA 14. On CUBE, the min-se setting defaults to 1800 seconds and can range between 90 and 86400 seconds 15​17. The min-se configuration is set globally under voice service voip sip and applies to all calls originated by the router 16. Cisco TAC notes CUCM sends a default Session-Expires of 1800 seconds, with an upper limit of 86400 seconds 22.

To avoid interoperability problems with UPDATE refreshes on CUCM 10.x onward, Cisco TAC advises configuring the session refresh method to INVITE 18. Cisco TAC also provides a CUBE SIP profile rule that strips UPDATE from the Allow header so that peer endpoints do not attempt UPDATE refreshes 21. When configured with midcall-signaling passthru media-change, CUBE absorbs refresh re-INVITEs locally and only forwards a session refresh to the opposing leg if the media characteristics change 19.

In a documented Cisco Customer Voice Portal (CVP) 11.6 deployment, calls disconnected at 30 minutes with CUCM sending a BYE containing cause code 41 due to a session timer negotiation mismatch 23. Cisco TAC determined that CVP dropped the call because it stripped session timer headers during re-INVITEs, causing each endpoint to believe the opposing side was responsible for refreshes 25. Cisco resolved this scenario by making the ingress CUBE the refresher via min-se 1800, session-expires 1800, and session refresh under voice service voip sip 24.

Microsoft Teams Direct Routing

Microsoft notes that Direct Routing calls dropping without error codes after 10 to 60 minutes of connection may indicate session timer or refresh failures 43. Microsoft explains that refresher=uac delegates refresh responsibility to the INVITE sender, whereas refresher=uas assigns it to the receiver 46. Direct Routing guidance recommends configuring the connected SBC so the designated entity sends refreshes before timer expiration, while tracing carrier-originated BYE messages back to their source 44. The Direct Routing SIP proxy always offers session timers on non-media-bypass calls, but omits them on media bypass calls 45. Utilizing session timers on the SBC is not mandatory for Direct Routing 47.

AudioCodes and Oracle SBC

AudioCodes Mediant Software SBC 7.4 sets SBCSessionExpires to a default of 180 seconds within a range of 90 to 86400 seconds 11. SBCMinSE ranges from 0 to 1000000 seconds and defaults to 0 9. Refresher selection is governed by SBCSessionRefreshingPolicy, which defaults to 0 (Remote Refresher) and offers 1 (SBC Refresher) 10. WarmTransfer's reading of the sources is that when the AudioCodes SBC acts as the refresher with SBCSessionExpires left at its 180-second default, session refreshes will occur roughly every 90 seconds under the RFC 4028 half-interval recommendation 8.

Oracle SBC 9.0.0 session-timer-profile defaults session-expires to 1800 seconds and min-se to 90 seconds, with minimum permitted values starting at 64 seconds 31. Its default behavior sets request-refresher to uac, response-refresher to uas, and force-reinvite to disabled 30. WarmTransfer's reading of the sources is that if an Oracle SBC session-timer-profile interval is configured between 64 and 89 seconds, an RFC 4028-compliant endpoint would reject the value as being below the standard 90-second minimum floor 29.

See also

Applicability

Applies to: IETF SIP, Cisco Unified Border Element, Cisco Unified Border Element (IOS XE), Cisco Unified Communications Manager, Cisco Unified CVP, Microsoft Teams Phone Direct Routing, Sangoma Asterisk chan_pjsip, AudioCodes Mediant Software SBC, and Oracle Communications Session Border Controller. Deployments: on-premises, hybrid, and multi-tenant. Sources checked 2026-09-25. Cisco TAC advises setting the session refresh method to INVITE instead of UPDATE for CUCM 10.x onward 18. Cisco Customer Voice Portal claims apply to CVP 11.6 23. AudioCodes SBC claims apply to Mediant Software SBC User's Manual version 7.4 11. Oracle SBC claims apply to ACLI Reference Release 9.0.0 31.

What remains uncertain

  • CUCM SIP profile session timer fields and defaults (SIP Session Expires Timer and Session Refresh Method) are not covered by the sources below.
  • Webex Calling Local Gateway and cloud session timer values and refresher role are not covered by the sources below.
  • Sources disagree on resolving whether current CUBE IOS XE initiates session timers by default or only with session refresh 20​14.
  • Operational impact of Direct Routing not offering session timers on media bypass calls is not covered by the sources below.
  • CVP Unified CM SME Enable Session Refresh and Enable Session Timer procedures are not covered by the sources below.
  • Session timer behaviour across transfer and hold and B2BUA leg splitting is not covered by the sources below.
  • Meaning of AudioCodes SBCMinSE value 0 and newer manual defaults are not covered by the sources below.
  • BYOC session timer requirements are not covered by the sources below.

See also

Applies to

Troubleshoots

  • Calls that drop after about 30 seconds — Contrast topic: 30-second drops are usually ACK or media problems while session timer failures drop calls at roughly the negotiated Session-Expires interval (commonly about 30 minutes)

Referenced by

Sources

  1. 1
    RFC 3311 recommends re-INVITE rather than UPDATE for session changes on confirmed dialogs because UPDATE needs an immediate answer.
    RFC 3311: The Session Initiation Protocol (SIP) UPDATE Method · Section 5.1 (Sending an UPDATE) · Checked 2026-09-25
  2. 2
    A 422 response must contain a Min-SE header.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 6 (422 Response Code Definition) · Checked 2026-09-25
  3. 3
    RFC 4028 defines 422 Session Interval Too Small, sent by a UAS or proxy when Session-Expires is below its minimum.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 6 (422 Response Code Definition) · Checked 2026-09-25
  4. 4
    After a 422, the UAC retries with a Min-SE equal to the largest Min-SE value returned in all 422 responses for that request.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.1 (Generating an Initial Session Refresh Request) · Checked 2026-09-25
  5. 5
    Support for UPDATE is signalled by listing UPDATE in the Allow header of the INVITE and of reliable provisional or final responses.
    RFC 3311: The Session Initiation Protocol (SIP) UPDATE Method · Section 4 (UPDATE Handling) · Checked 2026-09-25
  6. 6
    Asterisk res_pjsip defaults timers_min_se to 90 seconds and timers_sess_expires to 1800 seconds.
    res_pjsip - Asterisk Documentation · endpoint section, options 'timers_min_se' and 'timers_sess_expires' · Checked 2026-09-25
  7. 7
    Asterisk res_pjsip endpoint option timers defaults to yes and accepts no, yes, required, always and forced (an alias of always).
    res_pjsip - Asterisk Documentation · endpoint section, option 'timers' · Checked 2026-09-25
  8. 8
    If the AudioCodes SBC is the refresher and SBCSessionExpires stays at its 180-second default, refreshes would occur about every 90 seconds under the RFC 4028 half-interval rule.inferred
    Mediant Software SBC User's Manual Version 7.4 - SBC Parameters · SBCSessionExpires default, read with RFC 4028 Section 10 · Checked 2026-09-25
  9. 9
    AudioCodes Mediant Software SBC 7.4 parameter SBCMinSE ranges 0 to 1000000 seconds and defaults to 0.
    Mediant Software SBC User's Manual Version 7.4 - SBC Parameters · SBC Parameters table, SBCMinSE (CLI min-session-expires) · Checked 2026-09-25
  10. 10
    AudioCodes SBCSessionRefreshingPolicy chooses who refreshes, with 0 Remote Refresher as default and 1 SBC Refresher.
    Mediant Software SBC User's Manual Version 7.4 - SBC Parameters · SBC Parameters table, SBCSessionRefreshingPolicy (CLI sbc-session-refresh-policy) · Checked 2026-09-25
  11. 11
    AudioCodes Mediant Software SBC 7.4 parameter SBCSessionExpires ranges 90 to 86400 seconds and defaults to 180.
    Mediant Software SBC User's Manual Version 7.4 - SBC Parameters · SBC Parameters table, SBCSessionExpires (CLI sbc-sess-exp-time) · Checked 2026-09-25
  12. 12
    If no refresh arrives, the non-refresher should send BYE slightly before expiry, recommended at the lesser of 32 seconds and one third of the interval before it.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 10 (Performing Refreshes) · Checked 2026-09-25
  13. 13
    The letter x is reserved as the compact form of the Session-Expires header.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 4 (Session-Expires Header Field Definition) · Checked 2026-09-25
  14. 14
    The CUBE configuration guide states Cisco SIP gateways cannot initiate the use of SIP session timers but fully support them when another UA requests them.disputed
    Cisco Unified Border Element Configuration Guide (IOS XE) - SIP Session Timer Support · SIP Session Timer Support, restrictions / feature description · Checked 2026-09-25
  15. 15
    CUBE's min-se setting defaults to 1800 seconds.
    Cisco Unified Border Element Configuration Guide (IOS XE) - SIP Session Timer Support · SIP Session Timer Support, min-se command description · Checked 2026-09-25
  16. 16
    CUBE's min-se command is set in voice service voip sip mode and applies to all calls originated by the router.
    Cisco Unified Border Element Configuration Guide (IOS XE) - SIP Session Timer Support · SIP Session Timer Support, configuration task for min-se · Checked 2026-09-25
  17. 17
    CUBE's min-se value range is 90 to 86400 seconds.
    Cisco Unified Border Element Configuration Guide (IOS XE) - SIP Session Timer Support · SIP Session Timer Support, min-se command description · Checked 2026-09-25
  18. 18
    Cisco TAC advises setting the session refresh method to INVITE instead of UPDATE for CUCM 10.x onward to avoid UPDATE refresh interop issues.
    Troubleshoot Session Refresh on CUBE · Section 'Avoid Interoperability Issues with Update Refresh' · Checked 2026-09-25
  19. 19
    With midcall-signaling passthru media-change, CUBE consumes refresh re-INVITEs and passes a session refresh across to the other leg only when media changes.
    Troubleshoot Session Refresh on CUBE · Section 'Consumption of Mid-Call RE-INVITE/UPDATE' · Checked 2026-09-25
  20. 20
    On CUBE, the session refresh command under voice service voip sip adds a Session-Expires header to the outbound INVITE when the inbound leg had none.disputed
    Troubleshoot Session Refresh on CUBE · Section 'Avoid Interoperability Issues with Update Refresh' · Checked 2026-09-25
  21. 21
    Cisco TAC shows a CUBE SIP profile rule that removes UPDATE from the Allow header so peers do not choose UPDATE for refreshes.
    Troubleshoot Session Refresh on CUBE · Section 'Avoid Interoperability Issues with Update Refresh', SIP profile example · Checked 2026-09-25
  22. 22
    Cisco TAC states CUCM sends a default Session-Expires of 1800 seconds, which can be raised to a maximum of 86400.
    Troubleshoot Session Refresh on CUBE · Section 'Example Call Flows' · Checked 2026-09-25
  23. 23
    In a documented CVP 11.6 flow, calls dropped at the 30-minute mark when CUCM sent BYE with cause 41 after a session timer negotiation mismatch.
    Troubleshoot Session Refresh Timer with Cisco Customer Voice Portal · Problem section · Checked 2026-09-25
  24. 24
    Cisco's fix for the CVP case makes the ingress CUBE the refresher with min-se 1800 session-expires 1800 and session refresh under voice service voip sip.
    Troubleshoot Session Refresh Timer with Cisco Customer Voice Portal · Solution section, configuration example · Checked 2026-09-25
  25. 25
    Cisco TAC attributes the CVP drop to CVP omitting session timer headers in re-INVITEs so each endpoint could assume the other was the refresher.
    Troubleshoot Session Refresh Timer with Cisco Customer Voice Portal · Cause / Problem description · Checked 2026-09-25
  26. 26
    With Session-Expires 1800 and no refreshes, an RFC 4028 non-refresher following the recommended BYE margin would end the call about 32 seconds before 30 minutes, so drops clustered just under 30 minutes point to session timers.inferred
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 10 arithmetic applied to the Section 4 recommended value · Checked 2026-09-25
  27. 27
    When the Min-SE header is absent its value is taken as 90 seconds.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 5 (Min-SE Header Field Definition) · Checked 2026-09-25
  28. 28
    The Min-SE header value must not be less than 90 seconds when present in a request or response.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 5 (Min-SE Header Field Definition) · Checked 2026-09-25
  29. 29
    An Oracle SBC session-timer-profile could be set between 64 and 89 seconds, which an RFC 4028-compliant peer would treat as below the 90-second floor.inferred
    session-timer-profile (ACLI Reference, Release 9.0.0) · session-timer-profile valid values, read against RFC 4028 Section 5 · Checked 2026-09-25
  30. 30
    Oracle SBC 9.0.0 session-timer-profile defaults request-refresher to uac and response-refresher to uas, and force-reinvite to disabled.
    session-timer-profile (ACLI Reference, Release 9.0.0) · session-timer-profile parameters: request-refresher, response-refresher, force-reinvite · Checked 2026-09-25
  31. 31
    Oracle SBC 9.0.0 session-timer-profile defaults session-expires to 1800 and min-se to 90, each with a valid range starting at 64 seconds.
    session-timer-profile (ACLI Reference, Release 9.0.0) · session-timer-profile parameters: session-expires, min-se · Checked 2026-09-25
  32. 32
    A proxy may insert a Session-Expires header into a request that lacks one before forwarding it.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 8.1 (Processing of Requests) · Checked 2026-09-25
  33. 33
    A proxy may reduce Session-Expires but not below Min-SE, and should raise but must not lower Min-SE.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 8.1 (Processing of Requests) · Checked 2026-09-25
  34. 34
    RFC 4028 recommends the refresher send the session refresh once half the session interval has elapsed.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 10 (Performing Refreshes) · Checked 2026-09-25
  35. 35
    A session refresh request in a dialog with an active session timer should include the Session-Expires header.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.4 (Generating Subsequent Session Refresh Requests) · Checked 2026-09-25
  36. 36
    If a session refresh transaction times out or gets a 408 or 481 response, the UAC sends BYE.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 10 (Performing Refreshes) · Checked 2026-09-25
  37. 37
    The Session-Expires refresher parameter takes the value uac or uas to name which side performs refreshes.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 4 (Session-Expires grammar) · Checked 2026-09-25
  38. 38
    A re-INVITE refresh should carry an SDP offer even if nothing changed, and the offer must indicate no change by reusing the prior origin field values.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.4 (Generating Subsequent Session Refresh Requests) · Checked 2026-09-25
  39. 40
    If the 2xx response sets refresher=uac, the UAS must include Require: timer in that response.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 9 (UAS Behavior); extraction attributed it to Section 7.2, verify · Checked 2026-09-25
  40. 41
    RFC 4028 sets an absolute minimum session interval of 90 seconds, reasoned as a bit more than twice the time a SIP transaction can take on timeout.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 4 (Session-Expires Header Field Definition) · Checked 2026-09-25
  41. 43
    Microsoft says a Direct Routing call that drops without an error code after 10 to 60 minutes connected may indicate a session timer or refresh problem.
    Issues that affect inbound Direct Routing calls · Section 'Calls drop after a specific duration' > 'Calls drop after several minutes' · Checked 2026-09-25
  42. 44
    Microsoft's resolution is to configure the SBC so the correct party refreshes before expiry, and to trace any carrier-originated BYE back to its source.
    Issues that affect inbound Direct Routing calls · Section 'Calls drop after several minutes' > Resolution · Checked 2026-09-25
  43. 45
    The Direct Routing SIP proxy always offers the session timer on non-media-bypass calls and does not offer it on media bypass calls.
    Teams Phone System Direct Routing: SIP protocol · Section 'Session timer' · Checked 2026-09-25
  44. 46
    Microsoft's Direct Routing guidance says refresher=uac makes the INVITE sender responsible for refreshes and refresher=uas makes the INVITE receiver responsible.
    Issues that affect inbound Direct Routing calls · Section 'Calls drop after several minutes', Note · Checked 2026-09-25
  45. 47
    Microsoft states that use of the session timer by the SBC is not mandatory for Direct Routing.
    Teams Phone System Direct Routing: SIP protocol · Section 'Session timer' · Checked 2026-09-25
  46. 48
    Listing the option tag timer in Supported indicates a UA can perform refreshes according to RFC 4028.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · IANA considerations, option tag registration (reported as Section 12.3; verify) · Checked 2026-09-25
  47. 49
    If only the UAC asked for a session timer and the 2xx lacks Session-Expires, the UAC performs refreshes as if the response carried its requested value with refresher=uac.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.2 (Processing a 2xx Response) · Checked 2026-09-25
  48. 50
    If the UAC does not indicate Supported: timer, the UAS must set the refresher to uas.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 9 (UAS Behavior), Table 2 · Checked 2026-09-25
  49. 51
    When the UAC supports session timers but expresses no refresher preference, the UAS decides whether it or the UAC performs refreshes.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 9 (UAS Behavior), Table 2 · Checked 2026-09-25
  50. 52
    A UAS may reduce the Session-Expires value in its response but not below the Min-SE value in the request.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 9 (UAS Behavior) · Checked 2026-09-25
  51. 53
    RFC 3311 UPDATE lets a UA change session parameters such as media without changing dialog state, including before the initial INVITE completes.
    RFC 3311: The Session Initiation Protocol (SIP) UPDATE Method · Abstract · Checked 2026-09-25
  52. 54
    RFC 4028 recommends UPDATE rather than re-INVITE for refreshes when the UAC knows its peer supports UPDATE.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.4 (Generating Subsequent Session Refresh Requests) · Checked 2026-09-25
  53. 55
    RFC 4028's preference for UPDATE refreshes and RFC 3311's preference for re-INVITE on confirmed dialogs address different cases (content-free refresh versus user-visible session change) rather than contradicting each other.inferred
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 7.4, read with RFC 3311 Section 5.1 · Checked 2026-09-25
  54. 56
    The session timer extension works even when only one user agent in the dialog supports it.
    RFC 4028: Session Timers in the Session Initiation Protocol (SIP) · Section 3 (Overview of Operation) · Checked 2026-09-25

Documents

tier 1 standards and regulators

RFC 3311: The Session Initiation Protocol (SIP) UPDATE Method

IETF / RFC Editor · 2002-09-01 · accessed 2026-09-25

tier 1 standards and regulators

RFC 4028: Session Timers in the Session Initiation Protocol (SIP)

IETF / RFC Editor · 2005-04-01 · accessed 2026-09-25

tier 2 current vendor documentation

Cisco Unified Border Element Configuration Guide (IOS XE) - SIP Session Timer Support

Cisco Systems · 2026-04-25 · accessed 2026-09-25

tier 2 current vendor documentation

Issues that affect inbound Direct Routing calls

Microsoft · 2026-06-30 · accessed 2026-09-25

tier 2 current vendor documentation

Mediant Software SBC User's Manual Version 7.4 - SBC Parameters

AudioCodes · 2026-09-25 · accessed 2026-09-25

tier 2 current vendor documentation

session-timer-profile (ACLI Reference, Release 9.0.0)

Oracle · 2026-09-25 · accessed 2026-09-25

tier 2 current vendor documentation

Teams Phone System Direct Routing: SIP protocol

Microsoft · 2026-08-21 · accessed 2026-09-23

tier 2 current vendor documentation

Troubleshoot Session Refresh on CUBE

Cisco · 2018-10-18 · accessed 2026-09-25

tier 2 current vendor documentation

Troubleshoot Session Refresh Timer with Cisco Customer Voice Portal

Cisco Systems · 2020-07-22 · accessed 2026-09-25

tier 3 vendor-maintained repositories

res_pjsip - Asterisk Documentation

Sangoma / Asterisk project · accessed 2026-09-24

Cite this page

APA

WarmTransfer. (2026, September 25). SIP session timers. WarmTransfer. https://warmtransfer.net/knowledge/sip-session-timers

BibTeX

@misc{warmtransfer-sip-session-timers,
  title  = {SIP session timers},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sip-session-timers},
  note   = {Verified 2026-09-25}
}