cancel
Showing results for 
Search instead for 
Did you mean: 
cancel

How to implement CUCME in SRST Mode?

18743
Views
15
Helpful
1
Comments

 

 

Introduction

 

This document covers the configuration procedures for implementing Cisco Unified Communications Manager Express (CUCME) in Survivable Remote Site Telephony (SRST) mode.

 

CUCME in SRST Mode

 

SRST is an IOS feature that enables routers to provide call-handling support for Cisco IP Phones if they lose their connection to a remote Primary CUCM which can occur if the WAN connection to the main site is down.

 

When CUCME provides Cisco Unified SRST functionality, provisioning of phones is automatic. Most CUCME 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. The benefit is that CUCM users gain access to more features during fallback without any additional licensing costs.

 

Advantages of CUCME SRST

 

Using CUCME in SRST mode has several advantages compared to using standard SRST:

 

  • CUCME provides more telephony features than standard SRST.
  • CUCME in SRST mode allows a mix of preconfigured phones and directory numbers for phones and DNs that require individual settings and phones that are not configured but are learned by SNAP.
  • The additional features of CUCME can be leveraged by pre-configuring the required individual settings in CUCME to benefit SRST.
  • ephone configuration is based on MAC addresses, ephone-dn configuration is based on directory number.
  • All phones and DNs that collectively require identical configuration not provided by SNAP do not have to be preconfigured, but the additional configuration can be applied using templates.
  • These features allow flexible configuration of any CUCME feature in a scalable way because only those devices have to be preconfigured, which requires individual settings.

 

Phone Registration Process

 

When a phone loses connectivity to its CUCM, it registers to its configured SRST reference. If that SRST reference is CUCME in SRST mode, the CUCME router first searches for an existing preconfigured ephone with the MAC address of the registration phone. If an ephone is found the stored ephone configuration is used. No phone configuration settings provided by SNAP are applied, and no ephone template is applied.

 

If the ephone is configured with one or more ephone-dns, the stored configuration is used for the phone's ephone-dn or ephone-dns. If no ephone is found for the MAC address of the registration phone, CUCME adds the ephone and applies the ephone template if it is configured using SNAP. If the directory number exists, it is bound to the added phone; otherwise, the directory number is learned using SNAP. If it is configured, the ephone-dn template is applied.

 

Figure shows a topology that can use SRST fallback support using CUCME.

 

CUCME-1.bmp

 

CUCME Basic Configuration

 

CUCME Basic Configuration

 

The following example shows Cisco Unified CME Basic Configuration

 

telephony-service

max-ephones 5

max-dn 10

ip source-address 10.1.101.102 port 2000

create cnf-files

 

!

ephone-dn 6

number 3001

ephone-dn 7

number 3002

 

!

ephone 3

mac-address 0012.0154.5D98

type 7960

button 1:6

 

ephone 4

mac-address 0007.0E57.6F43

type 7961

button 1:7

 

!

dialplan-pattern 3 5215553... extension-length 4

!

!

 

Configuring CUCME for SRST

 

Configuring CUCME for SRST:

 

To enable SRST mode for CUCME, use the srst mode auto-provision command in telephony-service configuration mode,

 

CMERouter# configure terminal

 

CMERouter(config)# telephony - service

 

CMERouter(config- telephony)# srst mode auto-provision {all / dn / none}

 

CMERouter(config- telephony)# srst dn line-mode {dual / single}

 

 

Configuring ephone-dn template for SRST mode:

 

To specify an ephone-dn template to be used in SRST mode on a CUCME router, use the srsn dn template command in telephony-service configuration mode,

 

CMERouter# configure terminal

 

CMERouter(config)# telephony - service

 

CMERouter(config- telephony)# srst dn template template-tag

 

CMERouter(config- telephony)# srst ephone template template-tag

 

CMERouter(config- telephony)# srst ephone description string

 

 

CUCME for SRST mode configuration

 

The following example shows CUCME configuration in SRST mode

 

CMERouter# configure terminal

 

CMERouter(config)# telephony-service

 

CMERouter(config- telephony)# srst mode auto-provision none

 

CMERouter(config- telephony)# srst dn line-mode dual

 

CMERouter(config- telephony)# srst ephone template 1

 

CMERouter(config- telephony)# srst dn template 3

 

CMERouter(config- telephony)# srst ephone description

 

CMERouter(config- telephony)# max-ephone 10

 

CMERouter(config- telephony)# max-dn 30

 

CMERouter(config- telephony)# ip source-address 10.1.101.102 port 2000

 

CMERouter(config- telephony)# exit

 

CMERouter(config)# ephone-template 1

 

CMERouter(config-ephone-template)# keep-conference local-only

 

CMERouter(config)# ephone-dn-template 3

 

CMERouter(config-ephone-template)# hold-alert 25 idle

 

In this example, CUCME uses ephone-template 1 for newly added phones. This template configures conference to drop if no internal members are left in the conference.

ephone-dns, which are learned using SNAP, are configured to alert the users if a call is on hold for 25 seconds and the phone is idle. The description of learned phones should be CUCME SRST, and the ephone-dns should be dual-mode lines.

 

 

Related Information

Comments

Excellent work ...well documented.

CreatePlease to create content
Content for Community-Ad
August's Community Spotlight Awards