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szy
Occasional Contributor
Posts: 15
Registered: ‎01-16-2017
Accepted Solution

ISL links and port group for trunk - moving ISL link

[ Edited ]

Hello,

 

Looking to upgrade my ISL links between core switches (two out of three 6510s in each fabric), I've realised that instead of ISL's being trunked between two of them, they are just standalone ISLs.

 

What I'm seeing on one of the two switches in my first fabric (mirrored in the other one) is as follows:

 

:FID128:admin> trunkshow
  1: 32-> 12 10:00:x  19 deskew 15 MASTER
  2: 33-> 20 10:00:x  19 deskew 15 MASTER
  3: 46-> 27 10:00:x  31 deskew 15 MASTER
     47-> 31 10:00:x  31 deskew 16

Trunk 1 and Trunk 2 contain ports patched into the other core switch (DID 19), which normally I would epxpect to be part of the same trunk.

 

Trunk 3 confirms that a proper trunk formed to the third core switch (mesh), which only confirms that trunking licence is in place (in fact, this would only confirm licencing to be in place on switch with local domain and switch DID 31 but I did confirm that switch within DID 19 also has got it).

 

My two questions:

 

  • am I right in thinking that this is caused by the fact that for Trunk 1 and 2, ports on remote switch (DID 19) are in different port groups (port 12 and 20 are not within the same port group) and all that is required is to move ports on switch DID 19 to the same port group (ex. moving port20@DID19 to an empty port13@DID19)?

 

  • If so, what wold be the safest way of temporarily disabling one of the ISL links on switch DID 19, so that both ports are in the same port group and port trunk can be successfully created? Would portdecom be the best approach (am running 7.4.1)?

Checking portchannelshow from first switch to DID19, it is clear that both ports are used for routing to that switch so will using portdecom on one of the remote ports (ex. on port 20 @ DID 19, while moving it to port 13 @ DID19 ) cause any detrimental effect (I think there is plenty of bandwidth to let one ISL link handle the traffic while the other being switched over to corrrect port)?

 

:FID128:admin> portchannelshow
8 domain(s) in the fabric; Local Domain ID: 1

[...]

Domain: 19 Name: SWx WWN: 10:00:00x Port Channel: Ports: 32, 33

I would rather avoid part of infrastructure complaining about missing connctivity and dropped frames.

 

Have I missed on anything?

 

Thank you.

 

Regards,

Szy

Brocade Moderator
Posts: 258
Registered: ‎08-31-2009

Re: ISL links and port group for trunk - moving ISL link

[ Edited ]

Hello,

 

Yes port that need to participate to a same Trunk need to be in a same port group.

The best is to make sure that switches are using DLS with LOSSLESS enable (can be check with dlsshow command).

If not to enable it dlsset --enable -lossless on both switches.

Issue portdecom command

Move desired ISL to the same port group.

Then portcfgpersistentenable the concerned ISL port.

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution"
szy
Occasional Contributor
Posts: 15
Registered: ‎01-16-2017

Re: ISL links and port group for trunk - moving ISL link

One awesome answer! Thank you very much for clarifying on my doubts, Thierry.
szy
Occasional Contributor
Posts: 15
Registered: ‎01-16-2017

Re: ISL links and port group for trunk - moving ISL link

Hello,

May I have an extra question to this thread, please (just for completeness)?

Going through Dynamic Load Sharing (DLS) manual, what payed my attention is that this feature is switched off by default.

Is there any particular reason for that?

Is there a significant performance penalty when switching it on?

Is switching it on actually completely transparent to ongoing IO?

Thank you.

Regards,
Szy
szy
Occasional Contributor
Posts: 15
Registered: ‎01-16-2017

Re: ISL links and port group for trunk - moving ISL link

I think I can partially answer my own question:

 

DLS is enabled by default with EBR (exchange-based routing) but not with its lossless feature so DLS is not switched off by default as such.

 

DLS is set with Lossless disabled

Am still not 100% sure if act of turining it on actually causes any IO blip (I would assume it would not ...).

 

Regards,

Szy

Brocade Moderator
Posts: 258
Registered: ‎08-31-2009

Re: ISL links and port group for trunk - moving ISL link

Hello,

 

The activation of LOSSLESS is not disruptive.

 

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution"

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