SRST vs UCME with SRST

[abbas.ali]

In a centralized environment where the branches are remotely connected to Call Manager Cluster in a data center then what would be the appropriate solution as a backup for the branches in case they lose the WAN connectivity. SRST only or UCME with SRST.

I can't find any good doc on CCO where Cisco can explain in which deployment model UCME with SRST would be required or recommended.

Thx

[Marwan ALshawi]

generally the same

but if u want more spicific features to be kept for each phone with UCME with srst u can do it with more flexibility

hope this helpful

[Sushil Kumar Katre]

Hi Abbas,

Few points you need to take care -

CME in SRST mode does not supports Meet-Me conferencing.

SRST does not supports Unity Express.

CME in SRST mode will support lesser phones as compared to SRST for example 3825 in CME in SRST mode will support 240 phones while in STST mode it'll support 720 phones.

-> Sushil

[Markus Schneider]

SRST does support Unity Express... here are some facts about CME in SRST mode; the big ones being that CME in SRST mode requires more configuration, gets you more features, but supports less phones for a given platform:

- IP phones re-home to CME in event of CallManager failure & have access to advanced CME telephony features

- less phones supported

- No support for Vg248 registration during fallback

- Lack of support for “alias” command

- Support for Cisco Unity at remote sites

- Pickup Groups, Hunt Groups, B-ACD, Call Park, Softkey templates, paging

- No support for secure voice in SRST mode

- Requires more complex configuration

[Sushil Kumar Katre]

Hi MARKUS,

Thanks for pointing out.

Actually CME in SRST mode does not supports Unity Express.

Best Practices for Unified CME in SRST Mode

•Use SRST if deploying Cisco Unity Express at remote sites; Unified CME in SRST mode does not support Cisco Unity Express.

From SRND 6.1, page 50 SRND.

-> Sushil

[Chris Deren]

To summirize everyeone's responses, it depends on requirements.

If the customer only cares about getting phones calls and being able to dial out and some limited functionallity under SRST condition then legacy SRST will suffice.

If they require more features, i.e. hunting, pickup groups, call park, etc then CME as SRST would be a good solution (I personally love it).

HTH,

Chris

[Marwan ALshawi]

i agree with u Chris

but i think adding all IP phones with thiser MACs and ddetails long with CME/SRST while with SRST mor esimple right ?

[Chris Deren]

You dont have to do anything manually if you dont want to in CME as SRST you can utilize srst mode auto-provision.

Chris

[Marwan ALshawi]

hi Chris

could u please describe how auto-provision works

thank you

[Chris Deren]

It's very nicely described here:

http://www.cisco.com/en/US/docs/voice_ip_comm/cucme/admin/configuration/guide/cmesrst.html

HTH,

Chris

[Marwan ALshawi]

i have read it today thanks anyway :)

by the way the only option i confused with is the provesion none

none-Does not include information for learned ephones or learned ephone-dns in the running configuration. Use this keyword when you want Cisco Unified CME to provide SRST fallback services for Cisco Unified Communications Manager

didnt got it !!! i mean this part only ( Use this keyword when you want Cisco Unified CME to provide SRST fallback services for Cisco Unified Communications Manager)!