IP Phones Not Registering During call-manager-fallback/SRST Mode

[Matthew Martin]

Hello All,

Gateway: ISR4321/K9
IOS-XE Version: 03.13.04.S
IOS Version: 15.4(3)S4

I am trying to test the SRST failover of an ISR Router, but after I cut the connection to CUCM, the IP Phones never actually register to the Router. See below for configuration...

CALL-MANAGER-FALLBACK:

call-manager-fallback
  secondary-dialtone 9
  max-conferences 2 gain -6
  transfer-system full-consult
  timeouts interdigit 5
  protocol mode ipv4
  ip source-address 10.18.2.1 port 2000      !--> 10.18.2.1 is the Voice Vlan IP Address on ISR4321
  max-ephones 12
  max-dn 48
  default-destination 4019

I also configured a TEST-DP and a TEST SRST Reference on CallManager (*v8.6) and applied that Device Pool to the H.323 Gateway I added to CallManager for this ISR Router. Is there anything I am missing that also needs to be configured to have the Phones Register to the Gateway? I tried running "debug ephone register/state" but no information is printed to the logs when the connection to the CallManager is lost.

SRST Reference Configured on CUCM:

TEST-SRST
  Name: TEST-SRST
  Port: 2000
  IP Address: 10.18.2.1

This SRST Reference was then applied to the Device Pool I created which is what I set the H.323 Gateway's Device Pool too.

But, for some reason it doesn't seem like SRST is working at all. We have the FL-SRST and FL-CME-SRST-5 Licenses.

If anyone has any thoughts or suggestion, it would be very much appreciated.

Thanks in Advance,
Matt

[Matthew Martin]

Suresh, how do I check on DB Replication? Would that just be the "Cisco DB Replicator" service in Cisco Unified Serviceability > Network Services.? If it is, then it does show that it's running...

Also, not sure if this confirms its working or not, but if I log into the other 2 CallManagers that we have, they are both showing the most updated settings that I configured on the main Publisher.

-Matt

[Suresh Hudda]

You can check dbreplication from rtmt, unified reporting, and CLI. From cli use " utils dbreplication runtimestate", status should be 2 for all nodes.

Suresh

[Matthew Martin]

Ok thanks. I ran the CLI command it it says All DB Replication Services are running and in the table listing the CUCMs it shows all as "Connected". So from this output it seems like DBReplication is fine...

admin:utils dbreplication runtimestate 

DB and Replication Services: ALL RUNNING

Cluster Replication State: Replication status command started at: 2016-06-27-13-24
     Replication status command in PROGRESS 63 tables checked out of 541
     Processing Table: typecertificateservice

     Use 'file view activelog cm/trace/dbl/sdi/ReplicationStatus.2016_06_27_13_24_00.out' to see the details

DB Version: ccm8_6_2_24901_1
Number of replicated tables: 541

Cluster Detailed View from PUB (3 Servers):

           	         PING  	   REPLICATION	REPL.	DBver& 	REPL.	REPLICATION SETUP
SERVER-NAME	(msec) RPC?  STATUS     	QUEUE	TABLES 	LOOP?	(RTMT) & details 
-----------	        ------	   ----	   -----------	-----	-------	-----	-----------------
CUCM02		0.143  Yes	  Connected	0  	match	Yes  	(2) Setup Completed
CUCM01		0.055  Yes	  Connected	0  	match	Yes  	(2) PUB Setup Completed
CUCM03		26.8    Yes	  Connected	0  	match	Yes  	(2) Setup Completed

[Matthew Martin]

I think I figured out the problem.

Looks like the issue was that I did not have Device Mobility enabled for the IP Phones in the Test Device Pool...

First I needed to create a DMI (*Device Mobility Info) and add the TEST-DP to that DMI. Then, I needed to go to the Device Configuration pages of the IP Phones in that Device Pool and turn Device Mobility on...

After I did that I can now see the SRST Router IP Address in the "Unified CM Configuration" page of the IP Phones... So I cut the connection between the Router and the CUCM and after about 30-60 seconds the phones are now registering to the SRST Router..!

So, as I found out, Device Mobility needs to be enabled on each device in the DP and the Device Mobility Info setting on CUCM needs to have the correct Device Pool associated to it for SRST to work on the IP Phones...

Thanks again to all who replied, very much appreciated!

Thanks Again,
Matt

[Deepak Mehta]

That's good however i do not have device mobility for phones set up in my lab and it still works.So i am not too sure if that is the actual reason for it not working.

Also  phone will always list SRST reference even if they are registered to CUCM and have SRST Device pool applied.

[Matthew Martin]

Strange... I tested this again this morning and it was still not working. Then, after that failed test I did the Device Mobility Info settings in CUCM and then enabled Device Mobility on the IP Phones. After I applied the Configuration to the ip phones SRST suddenly started working and showing the SRST Reference in the Unified CM Configuration list on the phone. It does not seem like it was a coincidence, but I can't say for sure...

Thanks again,

Matt

[Deepak Mehta]

Thanks, I want to clear it for my knowledge .After reaserching a little i found that  If we have device mobility enabled then phone can dynamically learn about SRST reference.

I think after you gave subnet info in DMI and applied the phone got the reference.

[Matthew Martin]

Ok that makes sense, thanks for the info Deepak!

-Matt

[Matthew Martin]

Hey Deepak, quick question.

I was reading the instructions located at the link below about configuring SRST because I wanted to confirm a setting, and I noticed when they talk about configuring option 150 for the DHCP Pool, they do not mention including the SRST Router's IP Address as an option in the option 150 command...

http://www.cisco.com/en/US/products/sw/voicesw/ps2169/products_configuration_guide_chapter09186a00806674c3.html

They say to enter only the IP Address(es) of the Unified Communications Managers. So would it be safe, and/or recommended, to remove the SRST Router's IP Address and just keep the CallManagers' addresses in there?

Thanks in Advance,

Matt

[Deepak Mehta]

Hey Matt,

Yes, you can remove it ,because for SRST to work ,the important thing is default router as  phone should be able to contact the default router to register.

[Matthew Martin]

Ok great, thanks for the confirmation.

-Matt

[rajbirajmani]

i have a problem with phone registering to gateway in SRST mode. Below is the configuration i have on my gateway ISR4331

call-manager-fallback
max-conferences 10 gain -6
transfer-system full-consult
ip source-address 10.8.137.100 port 2000 ==> Gateway IP
max-ephones 50
max-dn 200

I have also created SRST reference in CUCM and applied it to DP and same DP is applied to all the phones and MGCP gateway in CUCM. My active server on phone is always pub and stand by server is sub. When I get down the pub phones do get registered to sub but when both are down phones just do not register at all.

[Georgios Fotiadis]

What type of phones are you trying to register at SRST?

Look if SRST gateway is listed on the phone CUCM list (look in phone settings or phone GUI - network setup/configuration). Also, ip source-address should match the SRST reference configured at CUCM.

[rajbirajmani]

Thanks for your reply Georgios, i am using Cisco 7841 phone. ip source-address is same in SRST reference in CUCM. I can only see active server as my subscriber address and stand by server as publisher address, i cannot see SRST gateway in the list. When i bring down the sub, the pub becomes active server and stand by server becomes none.

[Georgios Fotiadis]

The SRST IP address should appear in the list, otherwise it will never work. The 7841 is a SIP phone; your configuration is for SCCP phones. Make sure the SIP Network/IP Address is also populated in the CUCM SRST configuration. Then you need configure SIP SRST at you ISR. This should help: SIP in CME SRST