There is backbone router A (7600s).It's interface connections:
- access switches
- IP uplinks
- other backbone routers
Router A is used also for:
- transit of customer's vlans from access switches to other backbone routers (where they are terminated)
- BGP with directly connected uplinks (and routing of user traffic to them also).
- terminate few customer vlans on SVI's.
The is a VSPAN configured on router A. The source for VSPAN are transit vlans and vlan's that are terminated on router A SVI's.
The destination for this VSPAN is an interface of router A connected with IDS.
The problem is that during BH (busy hours) delays and overrun mistakes increase on uplink interfaces of router A.
There is a strange corellation with vlans, that are terminated on SVI's. When I drop them from VSPAN process delays become normal and viсe versa.
Here is VSPAN part of configuration:
monitor session 1 source vlan 4 - 20 , 28 - 30 , 34 , 35 , 37 rx
monitor session 1 source vlan 57 - 58 rx
monitor session 1 destination interface GigabitEthernet1/3