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Span and Rspan causes distorted voice in CCM

Hi all,

I have the following scenario:

- one stack of 3750 , where i connect a Call Manager and a sniffer software for call recording

- one remote 3560X where i connect a voice gateway router.

The sniffer software should be able to intercept packets from CM and VG.

So i have the following config:

On stack:

vlan X


monitor session 1 source interface Gi1/1 (Call Manager)

monitor session 1 destination interface Gi1/2 (sniffer)

monitor session 2 destination interface Gi1/3 (sniffer)

monitor session 2 source remote vlan X

On remote switch

vlan X


monitor session 2 source interface Gi1/1 (Voice Gw)

monitor session 2 destination remote vlan X

The X vlan is transported across the trunk, all ports are in trunk mode.

I can intercept calls on the sniffer software, the problem is that when i enable monitor session 2, the incoming calls from outside became robotic and distorted.

There is not very much proccesor consumption on both switches.

Any ideas?

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