HP 3800 Distributed trunking with stacking

[NikMiddleton]

Hi,

I have a pair of 3800's that are stacked.  What I want to do is have 1 server connecting via 2 NIC's to separate switches so that if a switch fails I have redundancy.  Bonding (linux) is set to Mode 4 on the server.

I know I can do dt-trunking using a port on each switch to link the pair, but question is:  Can I do this via the stack? (would really like to use the 36GB link)  If not what use is the stack apart from admin?

Thanks for any assitance on this

[Vince-Whirlwind · Accepted solution]

3800s stack properly, giving you a single virtual chassis.

To use the full bandwidth, you need to configure the two switchports as an aggregated link - either "trunk" or "LACP".

dt-trunking is for a trunk from a device to a pair of switches that are *not* stacked, so that's not what you want.

Obviously the server will have to support link aggregation as well.

[NikMiddleton]

Thanks for that, cleared things up for me.  Any benefits of trunking v LACP?

Note for those following later.  You need to add the trnk to the vlan (untagged) and not the ports in the trunk (it won't let you anyway) for traffic to flow.  If using the web front end, the trunks appear at the bottom of the list of ports

[Vince-Whirlwind]

"Any benefits of trunking v LACP?"

Whatever works.

View the traffic  stats on the physical members of the link.

Try both and see if the traffic is distributed any more evenly using one method or the other.