Cisco Unified SRST Administration Guide (All Versions) - Cisco Unified SIP SRST on Cisco 4000 Series Integrated Services Router

Publisher

Cisco Systems

URL

https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cusrst/admin/sccp_sip_srst/configuration/guide/SCCP_and_SIP_SRST_Admin_Guide/srst_sip_isr4000.html

Published

2026-04-25

Updated

unknown

Accessed

2026-09-25

HTTP status

200

License

Cisco documentation; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• SRST license usage is reported three minutes after the last configuration change. in context
• Unified SRST requires one SRST_EP license entitlement for each configured SIP or SCCP phone. in context
• Starting with Cisco IOS XE 17.18.1a, Smart Licensing reports SRST usage with the flex subscription entitlement tag SRST_EP_SUB across all supported platforms. in context
• Unified SIP SRST on the ISR 4000 was introduced in Unified SRST 10.0 (IOS XE 3.10S) and extended to all ISR 4000 models listed in the chapter in Unified SRST 10.5 (IOS XE 3.13S). in context
• SIP SRST is enabled under voice service voip with allow-connections sip to sip and, in the sip sub-mode, the registrar server command with optional expires max and min values. in context
• Unified SIP SRST on the ISR 4000 does not support transcoding, shared lines or mixed shared lines, video calling, or multicast MOH for SIP. in context
• The documented SIP SRST verification commands include show sip-ua status registrar, show voice register dial-peers, show dial-peer voice and show license summary. in context
• SIP SRST capacity is set under voice register global with max-pool (maximum SIP phone pools) and max-dn, and max-pool is platform-dependent. in context

Cite this source record

APA

WarmTransfer. (2026, April 25). Cisco Unified SRST Administration Guide (All Versions) - Cisco Unified SIP SRST on Cisco 4000 Series Integrated Services Router. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-srst-admin-sip-srst-isr4000

BibTeX

@misc{warmtransfer-cisco-srst-admin-sip-srst-isr4000,
  title  = {Cisco Unified SRST Administration Guide (All Versions) - Cisco Unified SIP SRST on Cisco 4000 Series Integrated Services Router},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-srst-admin-sip-srst-isr4000},
  note   = {Cisco Systems, accessed 2026-09-25}
}