7905 IP Phone Registration problem Via MPLS Network

[engineer_ecin]

Hello Team,

7905 are unable to register to CCM across the MPLS WAN. Whereas the other models 7940 IP PHONE are able to register across the MPLS wan.

To isolate issue ,

1)A common switch port connected 7940 working well, when used the same ethernet Switch port for 7905 its unable to registerwith CCM.

2) With Manual binding option on the wan router for 7905, still unable to register with CCM Via MPLS WAN.

3) With Mannual binding option Ip reach ability is there even when the IP phone unable to resister (able to ping from CCM to IP phone 7905).

4) The Voice payload traffic and signalling traffic are Marked under EF class over MPLS network.

5) On point to point link IP phone 7905 is able to register with CCM.

Q: Can any body explin what could be the possible solution or debugging Steps ?

Thanks in Advance

[umedryk]

The call manager and/or switches should be checked for Ethernet speed and duplex mis-matches. A mis-match can cause excessive packet loss leading to the above problem.

Try:

http://www.cisco.com/en/US/products/hw/phones/ps379/products_qanda_item09186a00800a6763.shtml