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Gambler_168259's avatar
Gambler_168259
Icon for Nimbostratus rankNimbostratus
Feb 12, 2015

F5 LTM 2000s Loop Issue with Cisco 6500 L3 Switch

We have deployed two F5 LTM 2000s Load Balancers for our client   1.These two load balancer are connected to each other using VLAN HA with their respective ports 1.3 2.Load Balancer-1 and Load Bal...
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StephanManthey's avatar
StephanManthey
Icon for Nacreous rankNacreous
Feb 12, 2015

Hi Gambler,

by configuring a VLANgroup you create a L2 connection between internal and external VLAN.

Is this technically required? Same L2 broadcast domain? Whenever possible I avoid using VLANgroups.

In case you have assigned VLANs in "tagged" mode to interfaces on the F5 you will need a corresponding "trunk" (Cisco terminology for VLAN tagging) on the Cisco gear.

By using VLAN tagging a single link or aggregated links (aka F5 trunk, aka Cisco channel) can be associated with multiple VLANs.

For troubleshooting on the F5 the tcpdump will help you: 
tcpdump -nnni 0.0 -e -c 1000

The "-e" parameter dumps L2 information (MAC address and vlan tag), the "-nnni 0.0" is dumping on all interfaces and prevents all level name resolution, the "-c 1000" just limits the number of packets to dump.

Perhaps you are already aware of all these aspects and I misunderstood your question.

Thanks, Stephan