Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Voice Recording via Span Port

Hi,

Running CCM 6.1 with one remote branch. The remote branch has it's own ingress voice gateway. All phones at the remote branch connects to one 4506 switch. We have a Voice recording solution in place recording via spanning a port on the switch.

Problem is that the voice recording quality is not great via this method. At first we thought it might be the Voice recorder but last week we did the following tests:

1.Connect laptop to same spanned port, captured packets and saved them. Playback was not great (same result as with Voice recorder).

2. Connect laptop to IP Phone (span the phone port to the PC), capture packets and saved them. Playback of this was perfect.

Switch config:

!

monitor session 1 source vlan 100

monitor session 1 destination interface Fa2/6

Anyone seen anything like this or have some pointers?

Thanks

Charl

8 REPLIES
New Member

Re: Voice Recording via Span Port

I would just check if switch isnt overutilized by this session, or if there are no errors on spanned ethernet interface. But it probably also occured to you...

New Member

Re: Voice Recording via Span Port

I would check to see what Codec is being used. Most recording solutions can only handle G711 and not even G722 (even though it is the same bandwidth....as a matter of fact....did you turn off the G722 advertising?)

New Member

Re: Voice Recording via Span Port

Hi,

It it mostly G711 calls but seeing as this is a callcentre, calls enter at the branch, traverse the WAN to get CVP treatment and then goes back to branch. Obviously using transcoders and MTP resources.

G722 has been turned off.

Re: Voice Recording via Span Port

How many ports are you spanning and are you spanning the port or the VLAN? Could it simply be that packets are being dropped due to congestion on the span port?

New Member

Re: Voice Recording via Span Port

HI,

Currently spanning the Vlan but TAC came back saying we should change it to the port. We will need to span about 22 ports.

Re: Voice Recording via Span Port

I would suggest try it while spanning a single port (like you did on the phone, but through the switch) and see what that does. It may just be an issue of overloading that one port. You can't get 22 straws into one mouth without a little dribbling.

New Member

Re: Voice Recording via Span Port

True true, but how are others doing it then. We have another site running CUCM 4.2 with the same vendor for voice recording and do the same vlan spanning with no problems.

Bronze

Re: Voice Recording via Span Port

What's the source of the poor quality? Are you missing packets? Do you duplicate packets?

WHen you span a VLAN, only do inbound packets, or you're likely to get packets both in and out- and you may end up with poor quality from that. (Taking a wild guess.)

1008
Views
0
Helpful
8
Replies
CreatePlease login to create content