VLANs Across Switches With LACP Trunks

[jamesps]

About your first question, the answer is yes and no. If you want your "stack" of HP ProCurves to be redundant then you will need separate links to the Cisco (right) and to the 3Com (left). It is STP/RSTP/MSTP's job to block the uplinked port on the ProCurve if that link is redundant. Even if your Cisco or 3Com is not STP aware, the ProCurve switches will detect it since they will be in the same broadcast domain.
One issue is choosing which is the root switch, those links will have the highest priority and because they all have the same speed you will have to define each port/link priority manually. You can choose them as they are in the diagram, doesn't matter.
To make the whole setup redundant, make sure you tag all the vlans on the ports used for trunking.
Other than these issues, your setup will be fully redundant and pretty simple to configure as well.
Check the manual because there are some parameters you need to play with, you need to tell the switch basically not to send BPDUs on the links connected to the 3Com and CISCO, so they would not "complain" in any way. But that is for "fine tuning" if you experience any issues.
Are your 3Com and CISCO LACP capable? If yes then it will help, I would leave ALL the ports LACP enabled to make sure there are no loops "by mistake". With no STP enabled LACP will save you and disable the appropriate ports to avoid the loops!

Hope this helps,
james

[jamesps]

I would not do any STP change without having access to the switches. In certain cases you need to disable the ports while enabling STP on them. You will notice high activity on the switch after STP has been enabled and even lost connectivity to it.

Even if you add another vlan, IP it and want to use it for management purposes, you can simply UNTAG (and not TAG) the uplink ports to the Cisco and 3Com. The packets should be switched by the VLAN "unaware" devices at the other end just fine. If they would be tagged then certainly it won't work. The only reason I would use the DEFAULT_VLAN VID 1 would be tagging the trunk ports. For servers and everything else I would create separate vlans as needed. You could use a "chassis like" setup this way especially if you run out of ports on the HPs.

james

[wtu]

May I have some examples regarding path cost fine tuning for uplink ports? Could you explain what does "chassis like" setup? When I roll out the new Procurves onto the production, if I power off the CISCO and 3Com first and then power them back on, would the Procurve switch with the highest priority set (priority 0) takes over the root bridge position?

Thanks!

[jamesps]

Please see the txt file attached. The ports 36-38 are connected to end nodes (servers), 48 is connected to the main uplink (that would be your Cisco or 3Com) and Trk1 is a LACP dynamic trunk connected to an identical switch serving as a redundant backup. This other switch is also connected to the same uplink as the other one.

How the STP will route the traffic is set in the 4-th column which is the path COST. That means the links with the lowest number have the highest priority. This has nothing to do with the fact that this is my root switch or not.

The primary link is the one with path cost 20000 and the Trk1 is higher which means lower priority (my backup).
With these being said, STP's job is to block the Trk1 path while my port#48 is still active because there have to be no loops. The path costs is something you will have to come up with that depending on your network infrastructure and where do you want to send the traffic through.

The documentation about STP is a great help. I would recommend using MSTP even on 2800 series. I noticed a lower CPU load when using vlans intensively (as the manual says).

james

[wtu]

Should I enable STP on Procurves? I did a show spanning-tree and receive Rapid Spanning Tree (RSTP) Information saying STP Enabled: No

I am confused somewhat. I know RSTP has been enabled but does it co-exist with STP on the Procurves?

[jamesps]

A ProCurve 2800 supports: STP, RSTP and MSTP. The last one can be configured using CLI only. The others can be configured with the Menu as well. They all accomplish the same thing. If you have STP already in place then you can use path costs to establish a certain traffic priority. If you want these switches to talk to other "older" devices which cannot understand RSTP or MSTP, then you would have to stay with "basic" STP. In most cases even RSTP works ok. You would need to check those devices specifications and what STP versions do they support.

james

[jamesps]

If you want you can enable STP on the ProCurves and it will "talk" to the other STP aware devices in your network creating a loop-free network. If you will have redundant links to the ProCurves then this is a must. If not then you will probably not have a need for it. When enabling STP on the trunked ports you will lose connectivity with the switches for a few moments while the tree is "built". That is normal and I think the manual recommends disabling the ports before doing that.

james

[wtu]

If I use Lacp trunks, do I configure the trunk ports lacp active? If I want to enable STP on trunked ports, do I remove "no spanning-tree edge-port" accordingly?

I am revising my configurations to switch from trunk type of trunks to lacp type. Can I have examples showing how may I configure lacp type trunks to enable the detection/adjustment/report of connectivity issues?

Thanks.

[wtu]

I made a change on two trunks. When I did a "show lacp" one trunk is showing yes under lacp partner while the other showing no, how would I fix it?
Why that happened?