SRST Not working

[Prashanth]

Hi Guys

We have installed SRST at remote site but when link to cucm goes down only few to be precise 2 Phones get register & rest Phone dont come up in srst mode.

The setup here is

CUCM :-10.5.1.10000-7

Remote GW:- C2900 Version 15.0(1r)M16

Phones :- Cisco 7821 & 3905

Configuration:-

voice service voip
ip address trusted list
ipv4 172.31.15.254
ipv4 172.31.100.21
ipv4 172.31.100.22
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
bind control source-interface GigabitEthernet0/1
bind media source-interface GigabitEthernet0/1
registrar server expires max 3600 min 120

voice class codec 10
 codec preference 1 g711ulaw
 codec preference 2 g729r8

voice register global
 mode srst
 max-dn 200
 max-pool 25

voice register pool  1
 id network 172.31.15.0 mask 255.255.255.0
 no digit collect kpml
 voice-class codec 10

call-manager-fallback
 secondary-dialtone 0
 max-conferences 8 gain -6
 transfer-system full-consult
 timeouts interdigit 5
 ip source-address 172.31.15.254 port 2000
 max-ephones 25
 max-dn 25
 system message primary SRST Mode active
 time-zone 31
 date-format dd-mm-yy

I have taken ccsip debugs and few outputs which i have attached.

[Manish Gogna]

Hi Prashanth,

If a couple of IP phones are registering fine in SRST then the overall SRST config looks good. Can you check if there is a diff in the phone model / firmware version / device pool or any other settings between these two working and the non-working phones in SRST?

Manish

[Prashanth]

Hi Manish

Today we tested again after making some changes in the remote nw topology ,so now all 3905 phones are registering but only  7821 phones are not regestring in srst mode.

Thanks

[Manish Gogna]

Can you recreate the issue and provide the packet capture from a 3905 as well as 7821 while transitioning from being registered to cucm to srst mode and getting regoistered / stuck. Please share the latest running config as well.

Manish

[Prashanth]

Hi Manish

Can you tell how to do that capture.

Thanks

[Manish Gogna]

You need to span the switchport to which these phone are connected, you will find nunmerous docs on the net like one below

https://supportforums.cisco.com/document/13891/how-configure-port-monitoring-span-catalyst-2940-2950-2955-2970-3550-or-3750-series

Manish

[Prashanth]

Hi

Manish I have attached the SPAN Capture for both the Phones.

3905 which registeres in srst.

7821 which does not register in srst.

Also Latest running config.

Thanks

[Manish Gogna]

Hi Prashanth,

I checked the captures, the 7821 with IP 172.31.15.105 and firmware 10.1.1 and the 3905 with IP 172.31.15.125  and firmware 9-2-1. The captures are incomplete for both of the scenarios. For both i see SIP register message towards 172.31.100.22 but nothing back from the server in response. I would suggest if the device pool is same for these phones then you should engage TAC for further assistance.

Manish

[Prashanth]

Hi Manish

Recently we added 8945 SCCP Phone at the site.

But we cannot call from that phone through local gateway in srst mode.

Rest all SIP Phones are working .

The config is same as provided earlier.

Can anyone please help on this.

Thanks

Prashant

[Chris Deren]

Are the phones that register SIP or SCCP? and the ones that do not register SIP or SCCP or both?

[Prashanth]

Hi Chris

All are SIP Phones.

[Chris Deren]

Are they all on this network:

172.31.15.0 mask 255.255.255.0

[Prashanth]

Yes.

[Chris Deren]

Can you provide answers to Manish's questions?

Also, when you browse the IP address of these phones does it show proper SRST reference?

[Prashanth]

Actullay i need to test that what manish is asking.

And when i browse through the IP Phone i dont see any srst refrence in IPv4 config for any phones including those who register.

Two 3905 phone which register show '!' mark beside extension number instead of displaying the srst message 'SRST mode active' does that mean the phone has switched over srst or no.

And one more thing in voice register global for the command mode it had  2 options esrst and cme...i selected esrst...and removed back...again i configured voice register global without any mode now by default its taking mode srst....does it has anything to do.