A trunk is a number of ports that are used together to increase bandwidth or increase redundancy in the event of a failure of a port. The HP procurve supports HP trunking and LACP. Then benefit of LACP over standard trunking is it supports standby links that will activate in the event of a port failure. The main reason fot NOT using LACP would be if the connecting switch did not support LACP. So if possible you should always use LACP. Here is how to setup a trunk on a HP procurve.
As always the first thing we need to do is enter config context
TechiesSwitch# Conf t
Once it there are a number of ways to add ports into a trunk. To add selected ports enter the below with comma`s between the port numbers
TechiesSwitch(config)# trunk 5,6,7 Trk1 LACP
In the above example we trunk ports 5,6 and 7, we give it a label of trk1 and we also tell it to use the LACP protocol. Below you can add contiguos ports by using the “-“.
TechiesSwitch(config)# trunk 10-20 Trk2 LACP
This means all ports from 10-20 are trunked.
If your ports where in VLAN`s , as soon as you trunk them they lose their VLAN membership, we need to run the command below to add them to a VLAN .By default when you create a trunk it becomes a member of the default VLAN.
TechiesSwitch(config)# vlan 5 tagged trk1
The command above tags the trunk group we created “trk1! to VLAN 5, to remove the tag we would add “no” before the command above.
To show our Trunk config we run the command as seen below.
TechiesSwitch(config)# show trunk
This will list your trunks.
To show what ports are members of what trunk use the command above but add on the trunk label.
TechiesSwitch(config)# show trunk trk1
Remember this may create a loop depending on your topology so you may need to enable spanning tree. If your trunk goes to a trunk on another switch you will need to enable it. If your trunk goes to two separate switches you will not.
TechiesSwitch(config)# spanning tree
That command by default enables MSTP on thee switch, enable it on the connecting switches also.