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SIP Error 488 Media Not accepted


I have a CUCM 8.6 setup with a growing number of users having CUCI-Lync clients on laptops. At one particular site users report not being able to connect to certain destination when connected to the LAN switch. Call Manager logs show the calls failing to SIP 488 Media not acceptable media. 

If they connect using the Cisco WLAN then their short dials work.

I went to site today and using a customer laptop and CUCI-Lync client confirmed that whilst plugged into the LAN I couldn't reach certain destinations. This is where it then got weird whilst changing nothing else I enabled my VPN client. My IP address changed but CUCi-Lync client registered with CUCM and I could then reach all destinations.

Nothing else was changed. CUCM subscriber remained the same. I am totally baffled as to how a Cisco LAN environment can have this impact.

Wireshark Call Flows attached would indicate to me its not a network problem. Comparison of a working and failed INVITE message doesn't show any discrepancy to me see attached.

Any and all suggestions welcome



If this problem is not fixed yet, may I have detailed Call Manager service traces? It will help indicate why CUCM sends 488. This is sent because of a media negotiation problem.

The traces will help.



Thanks I will speak to a colleague and see if we have the CUCM traces. I am going to the location of the CUCM on Monday to run a Wireshark. I need to elaborate more. The destinations that fail when connected to the network are not directly on the CUCM they are off a Mitel switch connected to CUCM via SIP trunk. It this connection I suspect is sending back the message to CUCM.

Definitely need those Call Manager traces. Is there by chance a firewall sitting between the clients and the Call Manager that could be potentially inspecting SIP? The SDPs were identical from what I saw on that capture leaving the client. The VPN might have bypassed this. 

Problem was due to CAC setting for video - even though we were not making video calls. Increased this value and problem was solved

I am facing given below issue over a remote site. From 8841 SIP phones at HQ, unable to call over 7945 SCCP phone. 7945 is connected through MPLS network. We can make calls by 79xx series phones. But 8841 model is unable to call. Message getting "Unable to Setup Call"

Given below trace,

2017/03/26 09:35:15.181|SIPL|0|TCP|IN||5060|SEP3C5EC30CF028||52900|2,100,13,75595.118^^*|2821505|3c5ec30c-f0280004-0a687747-6bd9dee9@|INVITE
2017/03/26 09:35:15.182|SIPL|0|TCP|OUT||5060|SEP3C5EC30CF028||52900|2,100,13,75595.118^^*|2821506|3c5ec30c-f0280004-0a687747-6bd9dee9@|100 Trying
2017/03/26 09:35:15.187|CC|SETUP|36608911|36608912|3349|3727|3727
2017/03/26 09:35:15.195|SIPL|36608911|TCP|OUT||5060|SEP3C5EC30CF028||52900|2,100,13,1.48132^*^*|2821508|3c5ec30c-f0280004-0a687747-6bd9dee9@|488 Not Acceptable Media

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