Cisco Catalyst 3850 with poor performance and packet loss
Posted on 2014-02-21
- Cisco Catalyst 3850 (IP Base) running as core switch
- Connection to WAN on SFP (500Mbps)
- Connection to LAN on Gbit
- SVI VLAN 50 providing internet to LAN with 2 VLANs, x.x.214.x/24 and x.x.217.x/24.
- Routing performed on this switch
After installation, one of the subnets in LAN were connected (.214) with normal performance and no problems whatsoever.
After a few weeks, the second subnet in LAN is added to the network using a fully transparent QinQ to a remote network. Only L2 Cisco equipment on the remote side of the QinQ.
After adding the second subnet we started getting strange issues:
- Packet loss against gateway (3850) from all parts of the network
- Only 12Mbps from WAN when connected to a VLAN 50 access port on the 3850.
- After rebooting the 3850, suddenly > 400Mbps on the same port, no configuration changes.
The packet loss and low performance has been riding the whole network ever since adding the secondary network, but since this is a production network we have not been able to disconnect the network with the .217 subnet for a longer period of time (yet shorter disconnects of 10+ minutes) have not resolved the problems.
- Related to the .217 subnet?
- Faulty 3850?
- Configuration issues?
- Suggestions for debug and resolving the problem?