Trunk Problems between a 5406zl and A5800AF-48G switches.

[PKSVEN]

Hi,

Short scenario is I have a top switch being the 5406zl and a number of A5800AF switches to be deployed in a star config from module "A" of the top switch.

Problem: Two ports on the "A" module of the 5406 are trunked with ports 53/54 on the A5800 switches which are similarly trunked. So we have multiple trunks on the 5406zl module "A" one to each A5800 switch. I have turned on STP on the 5406 and on the A5800's, however when I plug in both links to the switches I immediately start getting packet losses which rapidly escalate to 100% loss. If I pull one link of each trunk on the A5800 then everything returns to normal with no packet loss but it has to be every A5800 that has the second trunk port disconnected to return the network to stability.

So currently we are running with only one link to each A5800 and have the other link disconnected. It does not matter which 5800 has its second link connected we immediately see the packet losses start and then ramp up to 100% loss and affects all switches.

The 5406zl only has the option to enable STP or disable it, whereas the A5800 switches have a whole load of options under the MSTP setting such as STP, RSTP, MSTP and what protection to set.

We currently have both links set to TRUNK and both are set to AUTO for link speed.

So if anyone has a suggestion on how we can connect up our second port links for the trunks without encountering our packet losses and eventually the whole network fail I am all ears.  :)

[Pete W]

Post your trunking config from each side and I'll take a look.

[Vince-Whirlwind]

So you have two issues:

1. Your trunk configuration is not working

2. Your STP configuration is not working.

Even though you are trying to fix 1., you have discovered a second issue which really needs to be fixed as well.

2. Default STP mode on the 5800 is MSTP, on the 5400 it is STP. So you need to look at your STP config on the 5800s and make sure Commware and Provision switches are configured the same, change the STP mode on the 5400 to MSTP.

(spanning-tree mode mstp)

Also configure

spanning-tree config-name XXX

spanning-tree config-revision N

If your 5800s aren't using the default STP instance, then also configure

spanning-tree instance N vlan LIST

1. On the Comware switches, do a display link-aggregation verbose and post the results here.

On the Procurve side, it's pretty simple, eg - trunk a19-a20 trk1 lacp