Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

SRST / CME

Hi all,

I need some advice. we are carrently having a callmanager 6.1 at the head office and we need to have either a call manager express on the DR site or configure SRST at the remote DR site ISR. what will be the best practice? the plan is that should we have a disaster, we have to be able to recover or have telephone access on the DR site.

Any advice will be appreciated.

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Red

Re: SRST / CME

Hi Emmanuel,

You don't need a second "dedicated" router (the 3800 series should be perfect) :)

Cisco Unified Survivable Remote Site Telephony Version 4.1

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/product_data_sheet0900aecd805e1e79.html

Cisco Router Using Cisco Unified Survivable Remote Site Telephony

Components of Centralized Call-Processing Architecture

The Cisco Unified Communications system uses Cisco Unified Communications Manager in combination with Cisco Unified Survivable Remote Site Telephony which is embedded within Cisco IOS® Software, to help provide high-availability IP telephony to branch offices. When access to Cisco Unified Communications Manager from the branch office is impeded, for example, as a result of a WAN link failure, Cisco Unified Survivable Remote Site Telephony provides telephony backup services to help ensure that the branch office has continuous telephony service over the Cisco network infrastructure deployed in the branch. The enhanced reliability provided by Cisco Unified Survivable Remote Site Telephony makes the Cisco Unified Communications system a cost-effective solution to ensure telephony operation to all users in an organization, whether they are located in the headquarters or in a branch office.

Furthermore, in certain environments, the security of telephony communication is a critical requirement. The Cisco Unified Communications system supports secure telephony communication between any two phones in the network, whether those phones are in the headquarters facility or at a branch office. Cisco Unified Survivable Remote Site Telephony contributes to this secure telephony communication solution by supporting the same secure telephony protocols in the branch office when the branch loses communication with the centralized Cisco Unified Communications Manager.

How It Works

Cisco developed Cisco Unified Survivable Remote Site Telephony technology for all Cisco IOS Software platforms that support voice (refer to Table 3 for a complete list). The Cisco Unified Survivable Remote Site Telephony feature integrates network intelligence into Cisco IOS Software, which acts as the call-processing engine for IP phones located in the branch office during a WAN outage.

In a centralized call-processing model, the Cisco Unified Survivable Remote Site Telephony router facilitates automatic failover so that local calls and active calls from Cisco Unified IP phones to the public switched telephone network (PSTN) are maintained even if a WAN failure occurs. If the WAN link to a remote office fails and connection to the Cisco Unified CallManager for the domain is lost, the phones in that branch office automatically redirect to the Cisco Unified Survivable Remote Site Telephony router. The Cisco Unified Survivable Remote Site Telephony router automatically takes over and offers a rich set of telephony functions to help ensure business continuity with minimal impact. When the disrupted WAN link is restored, the phones automatically reregister with the original Cisco Unified CallManager-and again, no manual intervention is required. Cisco Unified Survivable Remote Site Telephony is accomplished through this integrated system with no additional hardware components

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/product_data_sheet0900aecd805e1e79.html

Hope this helps!

Rob

4 REPLIES
Hall of Fame Super Red

Re: SRST / CME

Hi Emmanuel,

There are two flavors of SRST (as shown below) and the one that you likely require is commonly referred to as Cisco Unified CME in SRST Fallback Mode (either one will work but CME in Fallback offers more features). 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

New Member

Re: SRST / CME

thanks very much for the reply.

As you said, I think Cisco Unified CME in SRST Fallback Mode is the best for my situation.

Is it possible to run this on the WAN router without any conflicts? I have Cisco 3800 ISR. Or will I need a dedicated router?

your help will be highly appreciated.

Hall of Fame Super Red

Re: SRST / CME

Hi Emmanuel,

You don't need a second "dedicated" router (the 3800 series should be perfect) :)

Cisco Unified Survivable Remote Site Telephony Version 4.1

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/product_data_sheet0900aecd805e1e79.html

Cisco Router Using Cisco Unified Survivable Remote Site Telephony

Components of Centralized Call-Processing Architecture

The Cisco Unified Communications system uses Cisco Unified Communications Manager in combination with Cisco Unified Survivable Remote Site Telephony which is embedded within Cisco IOS® Software, to help provide high-availability IP telephony to branch offices. When access to Cisco Unified Communications Manager from the branch office is impeded, for example, as a result of a WAN link failure, Cisco Unified Survivable Remote Site Telephony provides telephony backup services to help ensure that the branch office has continuous telephony service over the Cisco network infrastructure deployed in the branch. The enhanced reliability provided by Cisco Unified Survivable Remote Site Telephony makes the Cisco Unified Communications system a cost-effective solution to ensure telephony operation to all users in an organization, whether they are located in the headquarters or in a branch office.

Furthermore, in certain environments, the security of telephony communication is a critical requirement. The Cisco Unified Communications system supports secure telephony communication between any two phones in the network, whether those phones are in the headquarters facility or at a branch office. Cisco Unified Survivable Remote Site Telephony contributes to this secure telephony communication solution by supporting the same secure telephony protocols in the branch office when the branch loses communication with the centralized Cisco Unified Communications Manager.

How It Works

Cisco developed Cisco Unified Survivable Remote Site Telephony technology for all Cisco IOS Software platforms that support voice (refer to Table 3 for a complete list). The Cisco Unified Survivable Remote Site Telephony feature integrates network intelligence into Cisco IOS Software, which acts as the call-processing engine for IP phones located in the branch office during a WAN outage.

In a centralized call-processing model, the Cisco Unified Survivable Remote Site Telephony router facilitates automatic failover so that local calls and active calls from Cisco Unified IP phones to the public switched telephone network (PSTN) are maintained even if a WAN failure occurs. If the WAN link to a remote office fails and connection to the Cisco Unified CallManager for the domain is lost, the phones in that branch office automatically redirect to the Cisco Unified Survivable Remote Site Telephony router. The Cisco Unified Survivable Remote Site Telephony router automatically takes over and offers a rich set of telephony functions to help ensure business continuity with minimal impact. When the disrupted WAN link is restored, the phones automatically reregister with the original Cisco Unified CallManager-and again, no manual intervention is required. Cisco Unified Survivable Remote Site Telephony is accomplished through this integrated system with no additional hardware components

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6788/vcallcon/ps2169/product_data_sheet0900aecd805e1e79.html

Hope this helps!

Rob

New Member

Re: SRST / CME

thanks

487
Views
5
Helpful
4
Replies
CreatePlease login to create content