[cisco-voip] Codec negotiation

[Wes Sisk]

Yes, CIPC allows configuring a specific port to use for RTP:
http://www.cisco.com/en/US/docs/voice_ip_comm/cipc/2_1/english/administration/guide/cag21cfg.html#wp1043677

/wes

On Dec 8, 2011, at 10:42 AM, Scott Voll wrote:

is there a way to specify the ports that IPC, and 7961 phones use for there RTP stream?

I tested this morning with full access on the Anyconnect connection and it worked.  So I'm guessing it has to do with the anyconnect ACL we use:

15 elements; name hash: 0x1857c43a (dynamic)
 line 3 extended permit udp any any eq tftp 
 line 4 extended permit tcp any any eq 2000 
 line 5 extended permit udp any any eq 16384 
 line 6 extended permit udp any any eq 16385 
 line 7 extended permit udp any any eq 16386 
 line 8 extended permit tcp any host 10.0.2.200 eq www 
 line 9 extended permit tcp any host 10.0.2.199 eq www 
 line 10 extended permit tcp any host 10.0.2.199 eq 8080 
 line 11 extended permit tcp any host 10.0.2.200 eq 8080 
 line 15 extended deny tcp any any

Any idea what I'm missing?  This is the ACL I inherited from the previous person and it seemed to have worked, but since adding the Lan to Lan IPsec tunnel, I started having problems with it.

topology is IPC -- anyconnect -- ASA -- IPSEC L2L Tunnel -- 881 (router) -- 7961

TIA

Scott

On Thu, Dec 8, 2011 at 5:40 AM, Wes Sisk <wsisk at cisco.com> wrote:
It's difficult to say with the information available here.  This could just be an IP routing issue.  TAC case?  CM SDI traces. Packet Capture if available.

/wes

On Dec 7, 2011, at 6:24 PM, Scott Voll wrote:

There was some talk a week or two ago, about ASA compatibility with CM and having to keep them lock step.  Am I running into this kind of issue?  ASA 8.4.2 / CM 7.1.5?

Scott

On Wed, Dec 7, 2011 at 12:13 PM, Wes Sisk <wsisk at cisco.com> wrote:
SCCP devices advertise capabilities on registration.  Those capabilities are never renegotiated unless video is added/removed/invoked.

A little insight here -
CM tells the phones the codec it *should* receive in the OpenReceiveChannel sent to the phone. However, the phones do not trust that.  The phone figures out the codec it is receiving based on the first few RTP packets received.

If you are seeing ?? under codec I would be more suspecting of RTP not arriving at the phone.


SIP and H.323 advertise codecs on a per-call basis.  MGCP advertises codecs once during registration.

Regards,
Wes

On Dec 7, 2011, at 2:30 PM, Scott Voll wrote:

can anyone tell me how Codec negotiation works?  Specifically what ports it works on?

I have telecommuters using IPC 7.0.5 connecting with anyconnect (2.5) connecting to an ASA at the head end.  Calls to inside 7961's work fine.

but I also have 881's doing site to site VPN with 7961 hanging off the back coming into the same ASA.  That phone can call internal 7961 also.

The problem comes from IPC telecommuters calling 7961's behind the 881's.  When you place the call, it rings, they answer, the timer increments up.  But with a ?? it does not show a Codec.  It looks like we never negotiate the Codec.

is this a Version problem?  CM is 7.1.5 and ASA is 8.4.2.  I THINK it worked with ASA version 8.2.4 (but I Can't downgrade to double check).

Any other ideas?

I have a TAC case with the ASA team and they are like ya, the vpn connections work.... open a new ticket with the voice team.  And before I did so, I figured you guys are really smart and probably have deal with these kinds of issues.


Scott
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