Fibre Channel (SAN)

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Occasional Contributor
Posts: 13
Registered: ‎04-18-2008

process for trunking existing multiple ISLs

We need to improve performance resilience by trunking existing ISLs between 4100 switches in a campus location using LW single mode fibre.

Both are in same port group.

The older ISL is at 2Gb LW - all traffic runs over this in both fabrics (we have dual fabrics)

The newer ISL is healthy (at 4Gb LW) but is unused - no traffic whatsoever.

First question is this - why no traffic flow? Is it because of Port based routing policy? We must have this because of HP EVA CA replication (mustn't be exchange-based routing).

We want to replace the exsiting 2Gb GBICs with 4Gb LW GBICS and trunk the two links together - working one fabric at a time.

Are there any gotchas here?

My big question is: If i disable the existing 2Gb ISL will traffic switch to the newer 4Gb ISL?

Will be interested to hear of any views.............regards

John

External Moderator
Posts: 4,788
Registered: ‎02-23-2004

Re: process for trunking existing multiple ISLs

John,

i am not 100% sure but i think this procedure will Work.

I would replace Step-by-Step in the existing ISL Trunk Group those old 2GB SFP with new 4GB SFP, this must work without any impact.

My doubt is here only, are the currenct ISL / Trunking Port Speed set at Auto or Fixed as 2GB ?

When the Port speed are set as Auto is not necessary to disable the existing ISL Trunk, at this time is not necessary to create a New ISL trunking Group

TechHelp24
Occasional Contributor
Posts: 13
Registered: ‎04-18-2008

Re: process for trunking existing multiple ISLs

Techhelp24    

Thanks for your response.

The ports concerned are all set to Autonegotiate.

My curiosity is over why no traffic is flowing over the newly instated ISL at 4Gb LW - and that the switch will react to use this when i change the GBICs on the other link. My guess is that this is due to port-based routing.

rgds

john

External Moderator
Posts: 4,788
Registered: ‎02-23-2004

Re: process for trunking existing multiple ISLs

john,

--->>> My guess is that this is due to port-based routing.

i dont think the routing caused the problem.

Follow, replace please one 2GB SFP with a new 4GB SFP.

With caution..... and without any warranty, but i think this must work:

According a ISL Trunk consist a group of 2 or more Port, the ISL ( Interswitchlnk ) is redundant so the traffic dont have any impact.

After replace the old SFP 2 to 4 , set portDisable ( portnumber ) and the portEnable.

Is traffic flowing now ?

TechHelp24
Occasional Contributor
Posts: 13
Registered: ‎04-18-2008

Re: process for trunking existing multiple ISLs

Good morning

Perhaps i need to clarify ... the ports concerned here are P29 and P31  - they form their own trunk master, viz:

b1broc1:admin> trunkshow
  1: 28-> 28 10:00:00:05:1e:03:fb:32   3 deskew 15 MASTER
     30-> 30 10:00:00:05:1e:03:fb:32   3 deskew 15

  2: 29-> 29 10:00:00:05:1e:02:06:26   2 deskew 15 MASTER

  3: 31-> 31 10:00:00:05:1e:02:06:26   2 deskew 15 MASTER

31 (2Gb) is busy, 29 (4Gb) no traffic.

regards

john

External Moderator
Posts: 4,788
Registered: ‎02-23-2004

Re: process for trunking existing multiple ISLs

Hi John,

i have understand.

Please set as mentioned the 4GB Port 29 disable "portDisable" and then "portEnable", is probable the port is hungh after the SFP was replaced, and this is the reason that not traffic is flowing now.

TechHelp24
Occasional Contributor
Posts: 13
Registered: ‎04-18-2008

Re: process for trunking existing multiple ISLs

Not sure if my last response was posted correctly................yes i have done this (and had in the past).

No difference made. P29 marked as E-port N4 Healthy online.

I am however, concerned whether the ISL on P29 will  work correctly when i replace the GBIC on P31.

Your interest is appreciated.

thanks

External Moderator
Posts: 4,788
Registered: ‎02-23-2004

Re: process for trunking existing multiple ISLs

--->>> I am however, concerned whether the ISL on P29 will  work correctly when i replace the GBIC on P31.

I think when you replace the second 2GB SFP with a new 4GB, will work correct.

TechHelp24
Contributor
Posts: 53
Registered: ‎06-24-2009

Re: process for trunking existing multiple ISLs

Hi John,

This sounds strange to me. What does "trunkdebug 29 31" say? I am also surprised port 31 hasn't joined the existing trunk.

You might also want to try "portbuffershow 29" to see the buffer credit state.

Cheers,

Alastair

Occasional Contributor
Posts: 13
Registered: ‎04-18-2008

Re: process for trunking existing multiple ISLs

Alastair

It says this:

b1broc1:admin> trunkdebug 29 31
port 29 and port 31 speed is neither 2G norboth 4G

in other words they're not forming a trunk they each consist of their own master (ie with only themselves as members of the group).

What i'm having trouble getting my head around is why no traffic (at all) appears to flow across the 4Gb link on P29.

Next Sunday i'm going to swap the 2 Gb SFPs out with 4Gb's and find out!

rgds

john

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