HP trunk / LACP

[RicN]

Hello Procurve experts! :)

I have some questions regarding the trunking possibilites on HP switches.

If you know the answer for just one or two of the questions, I would still be grateful!


1. Is it possible to use a HP trunk with the other end-device something else than a Procurve switch? Could it be a NIC teamed server or a Cisco switch?


2. Which method would you say is the most common trunk method? HP trunk, LACP static or LACP dynamic?


3. How does the switches share the traffic through the physical links in a trunk (hp/lacp)? Is it correct that it does a hash of the DA/SA and the outcome of this hash is how the sharing is done? For example, if we have a trunk with two links, would it be something like (simplified) that all hashes that begins with 0-5 goes through link 1 and all 6-9 goes into link 2?


4. If I understand it correctly then all ports on Procurve switches has been default configured to use LACP passive, is that still so, even on newer switches and new firmware?


5. If I use a LACP trunk and configure it like a static LACP, that is, both sides are LACP passive, is LACP really used? If no LACP packets are being sent, is the protocol / standard LACP used or it technicaly just like the HP trunk?


6. Is it correct that if I use a LACP active/passive configuration, the trunk will be set up automaticly at switch startup and no configuration, like VLAN tagging status and similar? Is it practicaly possible to use active LACP if so?

[Matt Hobbs]

1. Yes

2. LACP Static

3. Yes and yes it would be something similar to what you have mentioned.

4. In the past LACP passive was enabled (5300, 3400, 2600), but the current lineup of products (5400, 3500, 2610, etc) all have LACP disabled by default)

5. One side must be configured as LACP Active otherwise the trunk will not come up and you'll end up with a nice loop instead (if STP is not enabled). HP Trunk just forces the ports into a trunk.

6. With Dynamic LACP, it will only support the default VLAN (unless you also use GVRP).

7. Have a look through this too: ftp://ftp.hp.com/pub/networking/software/LLDP-and-LACP-statement.pdf

[RicN]

Hello Matt, and thank you for your good answers!

>>1. Yes

Could you set up the Procurve side as HP trunk and the other side as Cisco FEC?


>5. If I use a LACP trunk and configure it like
>a static LACP, that is, both sides are LACP passive,
>is LACP really used? If no LACP packets are being
>sent, is the protocol / standard LACP used or
>it technicaly just like the HP trunk?

>>5. One side must be configured as LACP Active
>>otherwise the trunk will not come up and you'll
>>end up with a nice loop instead (if STP is not
>>enabled). HP Trunk just forces the ports into a trunk.

What I really was after is this: As I understand it, LACP only "speak when spoken to", that is when at least one side is configured as active. In that case the active side will start to negotiate the LACP options with the passive side and the LACP trunk will be set up.

But, if both sides are set as LACP static, will any LACP packets ever be sent? That is, is it really LACP being used, or is it just like a hp trunk?

(If both sides for example are configured like this:
trunk a1,a2 trk1 lacp)