ER-SPAN and traffic filtering
Posted on 2009-04-02
We are trying to span traffic from site A to site B. Site A is a VoIP telephony call centre and site B is a server building where the voice calls must be recorded. The Cisco floor switches in site A are configured to ER-SPAN the traffic to specific ports in site B, into which are plugged the voice recording servers. We're using ER-SPAN as its a layer 3 network architecture...this wont be changing.
We set up the SPAN and it sent ALL traffic to site B, and crashed the network. Ouch. We need to find a way to restrict or filter the traffic being spanned to be RTP traffic only (just the voice traffic, not someone downloading Shrek 2!)
Limitations with ERSPAN seem to be that we cannot apply an ACL to it, nor can we get the policy based routing right to try filter this traffic.
We're banged our heads together and are stuck! Any suggestions would be welcomed.