LinkAggregation/LACP between 2 HP 1920 48G possible 1920 to 195048G not possible / not working

[Softwarekontor]

Basics:

- We have 2 old 192048G (A/B) switches.

- They are connectes via 5 * RJ45  and dynamic link aggregation.

- This is working just fine. I can ping/transfer from anywhere to anywhere on these two.

Problem:

- Now we have a 3. 48G Switch, but now it is a 1950 (C).

- We tried to configure everything like on the 2 1920, but it is not working.

- If just ping from switch A to C, B to C,... nothing is going through.

Config:

-  A (5) <-> (5) B (5) <-> (5) C

- LinkAggregation (Bridged) Dynamic

- All defined ports (20) on all 3 switches are:

-- "Type" = trunk,

-- "PVID" =  1

-- "Permit VLAN List" = 100,200.

-- Untagged from VLAN 1

How can I see, like on the 2 1920, uder Network->LACP, the working or problems with LACP on the 1950? On the 1950 there is no LACP status site!? Or?

What do I miss? What can I try? Or maybe what is the best config?

Greetings

Bjoern

PS: If you need screens, or...just let me know....

PPS: This is more or less the howto we used for the 2 1920 -> https://www.youtube.com/watch?v=Y0d2XjKhlX4

[Vince-Whirlwind]

You're trying to troubleshoot two things at once. Reduce it to one problem at a time: get rid of the LACP config for the new switch, connect it via a single link and see if you get connectivity.

So is your problem a LACP problem, or a connectivity problem?

[Softwarekontor]

This I allready tried. It is an LACP problem between one of the 1920 an the 1950.

I can, or at the moment it is my working solution, connect via single link any of the 2 other 1920 switches with the 1950 and the connection is working. I can ping/reach between a single link connection anything from anywhere. The 2 1920 are also working fine via link aggregation with each other, and also by single link. Only the LACP between one of the two 1920 and the 1950 is not working.

[Vince-Whirlwind]

So, you have a single link with no bridge aggregation and it works fine.

Next step make a second link and make sure it works fine.  Disable link 1 and make sure link2 is working..

When you have two known good links, then create the bridge aggregation on one of them, get that working and then add the second link to the bridge aggregation.

Even though these are supposedly "HP" switches, the 1920s are in reality just re-branded anonymous stuff from Singapore (I think?), so you need to treat this as a multi-vendor exercise, in other words you need to find the combination of trunking options on each side that will let it work.
When trying to create trunks between different vendors, often you wouldn't try LACP as your first choice of what might work, so I'd be trying the 1920 side on "static" from the get-go.
The 1950 is re-branded 3COM, but you're still going to have the problem of guessing what the garbage in the GUI actually means in terms of configuration, unless you can figure out how to break into the proper CLI. Apparently in 3COM-speak, "dynamic" means static, or so I was told on another thread. I don't recall ever having trouble doing aggregated links on 3COMs, and I rarely use LACP so whatever it is, it can't be that hard or I would remember a struggle. Key words are "trunk" or "static", and LACP or 802.3ad should be off wherever possible.

[Softwarekontor]

At first thanks for your help!

A = 1. 1920

B = 2. 1920

C = 1950

• One link, without link aggregation, between A and B, A and C or B and C is working on any avaiable port
• At the moment between A and B there is a 3 port LACP dynamic link aggregation, which is working fine. I will destroy it and rebuild it as static one, but this only can happen on one of the next weekends.
• A static or dynamic link aggregation between B and C is also "working". All ports are in trunk mode, including the BAGG's, and the link is up, if the port/s on the corresponding 1920 are in same mode. It also doesnt matter, if I only took one or the desired 3. The problem with this link is always no ping or whatsoever is going over this aggregation / port/s. Through a "direct" link between those 2 switches pings aso are working well.
• All link aggregation ports on all switches are in VLAN 100,200 and in trunk mode. The rest on all switches are in the standard.
• Also all link aggregation ports are untagged from the standard VLAN.

Questions:

• I connected A<->B<->C, or would you connect A<->B<->C<->A over a static link aggregation with all ports in trunk mode?
• Do I have to put all link aggregation ports on all in only one VLAN, or A<->B in one VLAN and B<->C in another VLAN?

One of the next weekends i will be able to test anything we discuss. ATM I am trying, besides the working hours, only little changes / tests.

Greeting Bjoern