Network Management

Hi @Alexandros86, you wrote "I have three HP J9851A switches connected in a mesh configuration", can you specify how they are interconnected? Is your network topology based on a triangle where every Switch Aruba 5412R zl2 - placed on the triangle's vertex - is concurrently connected its neighbours? if so...you can't use LAG (Links Aggregation Group = as known as the "Port Trunking" - often used with LACP - in ArubaOS-Switch/ProVision OS jargons) because LAG requires to be initiated by (and it's OK in your case because you initiate your LAG on a standalone switch) and also terminated against a single logical entity (a single logical entity could be: a standalone Switch or a Virtual Stack of two or more Switches or a two member Cluster supporting MultiChassis-LAGs); in your case you can create a Port Trunk on, say, the Switch A but you can't terminate it against Switches B and C because those ones aren't part of a single logical entity (they aren't Stacked in a VSF, as example).

Sorry There are Four Core Switches with mesh Connection, no Trunk or lag or vsx and on this setup i want to Connect an new Aruba cx.

if i use the trunk uplinks on Ports , one will be from Lacp in block State or there is something Else in HP that i can use?

In the Future my Plan is to replace the Core with new Aruba in vsx and use MLAG for uplinks 

Hi, as written...forget about using a LAG (Port Trunking) from your Aruba 5412R zl2 Switches to the new Aruba CX, the only option you currently have is to use LAG (Port Trunking) between ONE of your four Aruba 5412R zl2 Switches (one and only one) and the new Aruba CX Switch (or Switches if you are dealing with a VSF Stack or a VSX Cluster).

If your Spanning Tree topology is correctly configured (on all involved Switches) you can eventually think to concurrently interconnect with two or more standalone links your new Aruba CX Switch by terminating these links against (one by one) the various Aruba 5412R zl2 Switches but this will cause the STP to kick in (to avoid the network loop you are causing on purpose) and that will forcefully disable all of them minus one left enabled (this to resolve the caused loop). I will avoid this approach if not carefully planned/configured (if your purpose is to have one enabled link and two or more disabled seen as potential not concurrent "standby" links capable to be enabled one at time in case the first link goes down).

It's better to sit down an plan what you want to achieve considering the Network Topology you want to use.

Sorry There are Four Core Switches with mesh Connection, no Trunk or lag or vsx and on this setup i want to Connect an new Aruba cx.

if i use the trunk uplinks on Ports , one will be from Lacp in block State or there is something Else in HP that i can use?

In the Future my Plan is to replace the Core with new Aruba in vsx and use MLAG for uplinks 

i ask my team leader if its possible to change the core switches to a new Aruba and use VSX between the both sides  east/west and after this i can connect new switches to both sides without problem.

Now the design is not good and cause more Problems.

STP is not configured on the switches, ask me not why i real dont know what the old engineer here had done.

For me the Design schould be clear with east/west with vsx connection 

Hi, as written...forget about using a LAG (Port Trunking) from your Aruba 5412R zl2 Switches to the new Aruba CX, the only option you currently have is to use LAG (Port Trunking) between ONE of your four Aruba 5412R zl2 Switches (one and only one) and the new Aruba CX Switch (or Switches if you are dealing with a VSF Stack or a VSX Cluster).

If your Spanning Tree topology is correctly configured (on all involved Switches) you can eventually think to concurrently interconnect with two or more standalone links your new Aruba CX Switch by terminating these links against (one by one) the various Aruba 5412R zl2 Switches but this will cause the STP to kick in (to avoid the network loop you are causing on purpose) and that will forcefully disable all of them minus one left enabled (this to resolve the caused loop). I will avoid this approach if not carefully planned/configured (if your purpose is to have one enabled link and two or more disabled seen as potential not concurrent "standby" links capable to be enabled one at time in case the first link goes down).

It's better to sit down an plan what you want to achieve considering the Network Topology you want to use.

Sorry There are Four Core Switches with mesh Connection, no Trunk or lag or vsx and on this setup i want to Connect an new Aruba cx.

if i use the trunk uplinks on Ports , one will be from Lacp in block State or there is something Else in HP that i can use?

In the Future my Plan is to replace the Core with new Aruba in vsx and use MLAG for uplinks