Forum Discussion

daboochmeister's avatar
Sep 24, 2011

Configuration guidance for multiple VLANs to one-armed connection

Hi - hope this isn't too basic a question, but we're having difficulty getting a configuration to work, and I can't find any specific guidance on certain details. I am working with tech support, and will be asking there, but wanted to pursue it here as well.



We're attempting to attach Big-IP 1600 to a Cisco 2000 series switch; the goal is to aggregate all 4 copper GbEs, to handle both our internal and external VLANs over that single aggregated link.



To do this, we have:



- Set the 4 switch ports to trunk mode, with our 2 VLANs allowed



- Set LACP to active for those switch ports



- Created a port channel, in which all 4 are included



- Connected cables to interfaces 1.1 - 1.4 on the 1600



- Created a "trunk" on the 1600, adding all 4 interfaces



- Created the two VLANs on the 1600, assigning the trunk as a tagged interface



- On the 1600, LACP is set to active, STP to passthrough



On the switch, we're using VPC, so no STP should in fact be occurring - i though passthrough would be innocuous, given that.



We can't see any traffic over the VLANs in question. The self-IPs we assigned to those VLANs aren't reachable from the switch, the switch doesn't appear reachable from the Big-IP. (This switch is fully configured for those VLANs, and other trunk-attached devices [e.g. ESXi servers] absolutely see the VLAN traffic, so nothing that fundamental with the switch config).



Any recommended diagnostic steps? Or does anything sound fishy about our config?



Thank you for any help!



Dave Bucci


Lockheed Martin


2 Replies

  • Layer1- are the cables properly connected. Are the port lights green or amber. Is the port speed and duplex set to auto.
  • Figured it out. It was our networking setup. I didn't describe this, but in fact, we're actually cross-wiring the 4 cables for redundancy, 2 to one switch, 2 to another, and using Cisco’s vPC to setup a portchannel across the 4 ports (that appears to the F5 like a regular etherchannel on a single switch, no spanning tree, etc.) … but we had 2 network guys involved, and one thought we were running all 4 cables to a single switch and using a regular, non-virtual port channel – so both were setup, and it was fubaring the ports.



    All better now! Thx.