Cisco Voice Guru

How you can configure CoR in CUCME in four minutes or less.

1. Open the CUCM SRND and search for “dial-peer cor custom”.
2. Copy the entire CoR example and paste into Notepad.
3. Remove the unneeded text commentary that is in between the commands.
4. Change “port 1/0:23″ with the correct POTS port number.
5. Change “prefix-digits” to “prefix” (depending on your IOS version).

Problem: After configuring SIP-based CUCME, I noticed that my SIP phones would intermittently re-register.  The phone would also be non-responsive when I tried to initiate outbound calls. Ironically, though, was that the SIP phones could receive calls.  During the troubleshooting phase, I tried everything I could think of.  I even made sure that the firmware on the SIP phone was the version explicitly stated in the CUCME Admin Guide.

Debugs: I ran the following debugs to gather logs: debug voice register events, debug voice register errors, debug ccsip message, debug ccsip info.  Based on the debugs, this is what I was seeing:

Resolution: Based on the logs, the phone was never receiving the 401 challenge to the register refresh request.  To correct this issue, I bound the SIP signaling to the interface used as the source address under voice register global.  In my case, this was Vlan400:

Conf t
Voice service voip
Sip
Bind control source-interface VLAN400
Bind media source-interface VLAN400
End

The phone has been stable and the registration refreshes successfully.

It seemed the phone was not receiving the 401 challenge to the register refresh.  Due to this the phone was resending the register without authentication information and the CUCME would again reject the request.  This process would repeat until registration timed out and the CUCME closed the TCP connection.  At this point the phone would reset and would successfully register.

This post attempts to lay out the basic commands needed for a functional CUCME SIP system.  I pulled this configuration off a Cisco TechNote and added my comments inline in red.  For those of you following my blog and also studying for the lab, do you see any commands that may be missing?

Read the rest of this entry »

Error:

During the SIP phone registration process, when you try to reset the phones from “voice register global” you experience the following error:

voice register global
create profile
reset
No contact info available for pool 1.
No contact info available for pool 2.

Explanation (by Vik Mahli):

If we only ever had local phones register to the CME we would never need the authenticate register command since the CME authenticates the MAC address of the SIP phone by comparing the result of an ARP request.

IF you have remote phones the above process cannot be used as an authentication mechanism (wiki ARP to find out why:-) and therefore we use a built-in procedure within the SIP protocol for authentication. This is called the SIP Digest Authentication mechanism. The user/passwd are sent to the phone in a cnf file (encrypted passwd) and during the registration process the user/passwd stored in the phone cnf file is compared with the credentials within the voice register pool.

The downside is that if you specify “authenticate register” globally ALL phones must use the SIP Digest Authentication mechanism. You can¹t have some phones use the ARP procedure and some phones use the SIP procedure.

Therefore if you specify authenticate register in voice register global then every Voice Register Pool will need a user/passwd. You have correctly identified (along with others) that all voice register pool’s must contain a username/password.  If you ever see the error “no contact info for pool x” it means the phone has not registered. You must use the “show voice register dial-peer” command to verify registration of a SIP phone.

If you do not see any dial-peers created for the SIP phones then use debug voice register events and debug ccsip messages for more info. With the SIP mechanism you should see the initial register get rejected (401 Unauthorized) and then the SIP phone RE-REGISTER (Register in response to the 401Unauth) except this time it registers with the credentials.

Vik Malhi ­ CCIE #13890, CCSI #31584

Senior Technical Instructor – IPexpert, Inc.

Working Configuration:

voice service voip
allow-connections sip to sip
sip
bind control source-interface Vlan400
bind media source-interface Vlan400
registrar server expires max 600 min 60
!
voice register global
mode cme
source-address 10.10.202.1 port 5060
max-dn 10
max-pool 2
authenticate register
time-format 24
date-format D/M/Y
create profile sync 0005445240328021
!
voice register dn  1
number 3005
name BR2 Phone 1
!
voice register dn  2
number 3006
name BR2 Phone 2
!
voice register template  1
dialplan 1
softkeys connected  Endcall Hold Trnsfer
!
voice register dialplan  1
type 7940-7960-others
pattern 1 3…
!
voice register pool  1
id mac 001B.D4C6.980A
type 7960
number 1 dn 1
template 1
dtmf-relay sip-notify
username 3005 password cisco
codec g711ulaw
!
voice register pool  2
id mac 0021.5555.D1F6
type 7961
number 1 dn 2
template 1
dtmf-relay sip-notify
username 3006 password cisco
codec g711ulaw