SRST vs CM - loss of features

Answered Question
May 28th, 2009
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Hi all,


When I configure SRSRT I understand that it is an exceptional situation and therefore when a phone looses connectivity with CM and falls into SRST mode, it also looses a big part of its configuration. That is, CSS, hunt groups, pickup groups and so on... keeping just basic call, call transfer and fwd, hold.


However, customer wants to keep all functionalities... But when phones are not registered they don't appear in the config, so I don't see how to apply corlists and all other things.


Should I configure manually all phones in order to apply the rest of features? Or it is not possible at all?

I couldn't find any documentation saying that I can or can't achieve that...


Any help would be highly appreciated.

Best regards,

Carmen

Correct Answer by Rob Huffman about 8 years 4 weeks ago

Hi Carmen,


Java is most correct here (+5 points buddy!)


There are two flavors of SRST (as shown below) and the one that you require is commonly referred to as Cisco Unified CME in SRST Fallback Mode. Here is the feature comparison;



SRST Fallback


This feature enables routers to provide call-handling support for Cisco Unified IP phones if they lose connection to remote primary, secondary, or tertiary Cisco Unified Communications Manager installations or if the WAN connection is down. When Cisco Unified SRST functionality is provided by Cisco Unified CME, provisioning of phones is automatic and most Cisco Unified CME features are available to the phones during periods of fallback, including hunt-groups, call park and access to Cisco Unity voice messaging services using SCCP protocol. The benefit is that Cisco Unified Communications Manager users will gain access to more features during fallback ****without any additional licensing costs.



Comparison of Cisco Unified SRST and

Cisco Unified CME in SRST Fallback Mode



Cisco Unified CME in SRST Fallback Mode


• First supported with Cisco Unified CME 4.0: Cisco IOS Software 12.4(9)T

• IP phones re-home to Cisco Unified CME if Cisco Unified Communications Manager fails. CME in SRST allows IP phones to access some advanced Cisco Unified CME telephony features not supported in traditional SRST

• Support for up to 240 phones

• No support for Cisco VG248 48-Port Analog Phone Gateway registration during fallback

• Lack of support for alias command

• Support for Cisco Unity® unified messaging at remote sites (Distributed Exchange or Domino)

• Support for features such as Pickup Groups, Hunt Groups, Basic Automatic Call Distributor (BACD), Call Park, softkey templates, and paging

• Support for Cisco IP Communicator 2.0 with Cisco Unified Video Advantage 2.0 on same computer

• No support for secure voice in SRST mode

• More complex configuration required

• Support for digital signal processor (DSP)-based hardware conferencing

• E-911 support with per-phone emergency response location (ERL) assignment for IP phones (Cisco Unified CME 4.1 only)



Cisco Unified SRST


• Supported since Cisco Unified SRST 2.0 with Cisco IOS Software 12.2(8)T5

• IP phones re-home to SRST router if Cisco Unified Communications Manager fails. SRST allows IP phones to have basic telephony features

• Support for up to 720 phones

• Support for Cisco VG248 registration during fallback

• Support for alias command

• Lack of support for features such as Pickup Groups, Hunt Groups, Call Park, and BACD

• No support for Cisco IP Communicator 2.0 with Cisco Unified Video Advantage 2.0

• Support for secure voice during SRST fallback

• Simple, one-time configuration for SRST fallback service

• No per-phone emergency response location (ERL) assignment for SCCP Phones (E911 is a new feature supported in SRST 4.1)



http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/prod_qas0900aecd8028d113.html



Hope this helps!

Rob




Correct Answer by Jaime Valencia about 8 years 4 weeks ago

What you need then is CME-as-SRST to support more features


HTH


java


if this helps, please rate

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Correct Answer
Jaime Valencia Thu, 05/28/2009 - 03:56
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What you need then is CME-as-SRST to support more features


HTH


java


if this helps, please rate

Correct Answer
Rob Huffman Thu, 05/28/2009 - 04:59
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Hi Carmen,


Java is most correct here (+5 points buddy!)


There are two flavors of SRST (as shown below) and the one that you require is commonly referred to as Cisco Unified CME in SRST Fallback Mode. Here is the feature comparison;



SRST Fallback


This feature enables routers to provide call-handling support for Cisco Unified IP phones if they lose connection to remote primary, secondary, or tertiary Cisco Unified Communications Manager installations or if the WAN connection is down. When Cisco Unified SRST functionality is provided by Cisco Unified CME, provisioning of phones is automatic and most Cisco Unified CME features are available to the phones during periods of fallback, including hunt-groups, call park and access to Cisco Unity voice messaging services using SCCP protocol. The benefit is that Cisco Unified Communications Manager users will gain access to more features during fallback ****without any additional licensing costs.



Comparison of Cisco Unified SRST and

Cisco Unified CME in SRST Fallback Mode



Cisco Unified CME in SRST Fallback Mode


• First supported with Cisco Unified CME 4.0: Cisco IOS Software 12.4(9)T

• IP phones re-home to Cisco Unified CME if Cisco Unified Communications Manager fails. CME in SRST allows IP phones to access some advanced Cisco Unified CME telephony features not supported in traditional SRST

• Support for up to 240 phones

• No support for Cisco VG248 48-Port Analog Phone Gateway registration during fallback

• Lack of support for alias command

• Support for Cisco Unity® unified messaging at remote sites (Distributed Exchange or Domino)

• Support for features such as Pickup Groups, Hunt Groups, Basic Automatic Call Distributor (BACD), Call Park, softkey templates, and paging

• Support for Cisco IP Communicator 2.0 with Cisco Unified Video Advantage 2.0 on same computer

• No support for secure voice in SRST mode

• More complex configuration required

• Support for digital signal processor (DSP)-based hardware conferencing

• E-911 support with per-phone emergency response location (ERL) assignment for IP phones (Cisco Unified CME 4.1 only)



Cisco Unified SRST


• Supported since Cisco Unified SRST 2.0 with Cisco IOS Software 12.2(8)T5

• IP phones re-home to SRST router if Cisco Unified Communications Manager fails. SRST allows IP phones to have basic telephony features

• Support for up to 720 phones

• Support for Cisco VG248 registration during fallback

• Support for alias command

• Lack of support for features such as Pickup Groups, Hunt Groups, Call Park, and BACD

• No support for Cisco IP Communicator 2.0 with Cisco Unified Video Advantage 2.0

• Support for secure voice during SRST fallback

• Simple, one-time configuration for SRST fallback service

• No per-phone emergency response location (ERL) assignment for SCCP Phones (E911 is a new feature supported in SRST 4.1)



http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/prod_qas0900aecd8028d113.html



Hope this helps!

Rob




mcibanez Thu, 05/28/2009 - 07:18
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Many thanks for your help and your quick responses, guys.


Best regards,

Carmen

Rob Huffman Thu, 05/28/2009 - 08:33
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Hi Carmen,


You are most welcome! Glad to be of some small help here.


Cheers!

Rob

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