SIP SRST

[Bekzod Fakhriddinov]

Hi guys, I was reviewing sip srst configuration from  a different sources and didn't see any ephone-dn configuration , how router will know which dn must be registered ?

example of the config:

voice service voip
ip address trusted list
ipv4 10.210.255.11
ipv4 10.210.255.12
ipv4 10.210.255.13
ipv4 10.210.255.14
ipv4 10.210.255.15
ipv4 10.210.254.2
ipv4 10.210.254.6
ipv4 191.0.0.0 255.255.255.0
ipv4 10.210.100.0 255.255.255.0
allow-connections h323 to h323
allow-connections h323 to sip
allow-connections sip to h323
allow-connections sip to sip
fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback none
sip
registrar server expires max 600 min 60
!!!!!!

!!!!!!

voice register global
mode srst
max-dn 100
max-pool 15
!
voice register pool 11
id network 10.210.24.0 mask 255.255.255.0
preference 2
proxy 10.210.24.253 preference 1
no digit collect kpml
dtmf-relay rtp-nte sip-notify
codec g711ulaw
no vad
!!!!!!

!!!!!!!

!
call-manager-fallback
secondary-dialtone 0
max-conferences 8 gain -6
transfer-system full-consult
ip source-address 10.210.24.253 port 2000
max-ephones 35
max-dn 100 dual-line
system message primary CM Fallback Service Operating
system message secondary CM Fallback Service
time-format 24
date-format dd-mm-yy
!

[R0g22]

You don't need to provision DN's with default SRST/fallback mode. If you have requirements to use specific features that need DN's to be specifically configured, let's say for hunt group, you would use a telephony-service with provisioning enabled or ESRST for SIP Phones.

[Bekzod Fakhriddinov]

at this case user can enter any extension on his phone and be registered on the router, correct ? 

I see "dialplan-pattern 1 732549.... extension-length 4" <- this I guess controls extension length on that phone. 

[R0g22 · Accepted solution]

That's correct but that would be pre-SRST. They won't be able to make any extension changes during SRST.

The command is to expand ANI from a 4 digit length extension to a DID/E.164 number.

[gmgarrian · Accepted solution]

The phone itself will create the appropriate virtual dial peer when it registers via SRST.  You maximums are defined here:

voice register global
mode srst
max-dn 100
max-pool 15

Plus, it will only allow phones to register that are from the subnet defined in the pool.

The user doesn't enter an extension, the IP phone registers to the SRST router with the same DNs it was assigned by CUCM.

[Bekzod Fakhriddinov]

right, they have assigned DNs already, I had confused with thing we use EM in the office, when users enter their EM extension to login. 

Thank you