What is SRST mode on a Cisco router?
A Cisco router in SRST mode provides call setup and call teardown services similar to CUCM, but only when connectivity to the CUCM servers provided in the Cisco Call Manager group are not reachable. SRST technology is widely used in the centralized call processing model where branch sites do not have any local call processing capabilities.
What does SRST stand for?
Survivable Remote Site Telephony (SRST) is a Cisco Unified Communications Manager (CUCM) call processing backup mechanism that allows Cisco IP phones to register to a Cisco router.
How do I configure the SRST reference configuration?
On the SRST Reference Configuration page, enter a name in the SRST Reference Name field and the IP address of the Cisco SRST router in the IP Address field. Click Insert . Apply the SRST reference or the default gateway to one or more device pools.
What is SRST fallback mode in VoIP?
In this case, you VoIP calls inter-clusters will not work as the WAN link is down but however calls made to the local site will work as the phones will be registered to the local router. As the Phone will register to the local site, the mode is called as SRST Fallback Mode.
What is SRST used for?
SRST is a licensed feature available on Cisco voice routers that allows Cisco IP phones to register with the gateway if these keepalive messages are lost. Cisco IP phones exchange the keepalive messages every 30 seconds by default.
What does SRST mean on a Cisco phone?
Survivable Remote Site TelephonySRST. Survivable Remote Site Telephony (SRST) is a Cisco Unified Communications Manager (CUCM) call processing backup mechanism that allows Cisco IP phones to register to a Cisco router.
What is the SRST in VOIP?
Cisco Unified SRST enables routers to provide basic call-handling support for Cisco Unified IP Phones when they lose connection to remote primary, secondary, and tertiary CUCM servers or when the WAN connection is down.
What is SRST configuration?
Pasha Teplitsky SIP, Unified Communications. Cisco SIP SRST Configuration is the process of providing backup to external SIP Call control (IP-PBX) through the provision of the basic registrar and re-direct server or back-to-back user agent (B2BUA) services.
What is SRST reference in CUCM?
CUCM SRST configuration is similar for both Cisco Unified SRST or Cisco Unified CME-based SRST. The IOS router must be defined as an SRST reference in CUCM. Then this SRST reference consecutively needs to be added to the appropriate device pool to enable the phones at remote sites to leverage SRST.
What is CME SRST?
Viewing the output of show license detail cme-srst indicates that there is no configuration present and the EULA has not been accepted.
How do you test SRST?
SRST testingCreate an ACL that blocks the remote router and a local phone(s) from reaching the Call Manager servers.Check how long it takes for the router PSTN ports to register to the router.Check how long it takes for the phone(s) to register to the router.Dial-plan (off-net and on-net calls). ( On-net only ).
What is MGCP fallback?
MGCP fallback enables a gateway to act as local call control when the CUCM server to which the remote site phones and gateway register is offline or WAN connectivity is lost (in which case, Cisco Unified SRST kicks in and offers call control functionality).
What is Cisco CME?
Cisco Call Manager Express (CME) is an enhanced IP telephony solution that is integrated into Cisco IOS. It is an ideal solution for small business customers to efficiently use their existing IP data connectivity to incorporate the deployment of voice and IP telephony.
What port does SCCP use?
TCP Port 2000TCP Port 2000 is the port reserved for Cisco SCCP (Skinny) Protocol.
What is SRST reference?
An SRST reference is the IP address of the Cisco Unified SRST Router.
Can a unified SRST router be multicast?
For Unified SRST 3.0 and later versions, you can configure the MOH audio stream as a multicast source. A Unified SRST router that is configured for multicast MOH also transmits the audio stream on the physical IP interfaces of the specified router to permit access to the stream by external devices. Certain IP phones do not support multicast MOH because they do not support IP multicast. You can disable multicast MOH to individual phones that do not support multicast. Callers hear a repeating tone when they are placed on hold.
