CUCM 7 :- Span to PC does not seem to work

Answered Question
Oct 9th, 2009
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Hi,


I have a PC, on which I can capture packets from my IP Phone registered to CM 5.1.3.

PC and Phone are on seperate VLANS.




When I move the same PC to a phone registered with CUCM 7, I cant see the RTP / SCCP packets.


I *have* enabled SPAN to PC Port.

I *have* enabled Voice Clan access



I have tried with 7941 / 42 and 45.


It *DOES* work, if the PC is on the same VLAN as the CM7 phone though.


None of them work.


The Firemware on the phones is SCCP-xx-8-4-1S where XX is the phone model (42/45).


Anyone come across this ?



Correct Answer by gogasca about 7 years 6 months ago

You are in the correct path:


PC Port set to enabled

PC Voice VLAN Access set to enabled

Span to PC Port set to enabled


Save and reset the phone so that it will pick up these attributes. This will

allow a network trace to be captured out the pc port of the phone


Once you do this access the phone web page and verify from there if changes are there or configuration file cannot be retrieved?

If that's the case you can try restarting TFTP.


Check: CSCsy34687



Some PCs can't sniff tagged packets but please take a look at this:


Some network cards strip the dot1q headers, so your packet capture won't

have this data. If you're not seeing dot1q headers please check the

following link from wireshark:


http://wiki.wireshark.org/CaptureSetup/VLAN#head-81781716144f2855ab0aff2f8b752e95f2562efb


Apply the previous settings to the machine you're capturing with.



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Correct Answer
gogasca Mon, 10/12/2009 - 12:30
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You are in the correct path:


PC Port set to enabled

PC Voice VLAN Access set to enabled

Span to PC Port set to enabled


Save and reset the phone so that it will pick up these attributes. This will

allow a network trace to be captured out the pc port of the phone


Once you do this access the phone web page and verify from there if changes are there or configuration file cannot be retrieved?

If that's the case you can try restarting TFTP.


Check: CSCsy34687



Some PCs can't sniff tagged packets but please take a look at this:


Some network cards strip the dot1q headers, so your packet capture won't

have this data. If you're not seeing dot1q headers please check the

following link from wireshark:


http://wiki.wireshark.org/CaptureSetup/VLAN#head-81781716144f2855ab0aff2f8b752e95f2562efb


Apply the previous settings to the machine you're capturing with.



shahedvoicerite Mon, 10/12/2009 - 13:33
User Badges:

Thanks.


It seems to be an issue with my network adapter, as I can sniff packets when I attach another PC to the phone.



Its odd because the same PC, which does not work with a 7941/42/45 attached to CUCM7, does work with a 7960 phone attached to CM5.


switchport settings on the Cat 2950 which connect the CM and phone/pc are identical in all cases!



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