Fibre Channel (SAN)

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Occasional Contributor
Posts: 6
Registered: ‎02-08-2016

Difference in behaviour between seperate ISL and ISL trunks

Hi all,

 

What we are lookig for is a document (ideally a table) that shows at a glance the differences in beheviour and characteristics if someone were to use standard ISLs vs an ISL trunk.

Say for example we had 2 switches and we could either join them via 4 seperate ISLs or we could use trunking to merge those 4 ISLs into one link what would the differences in throughput patterns, failover, physical link utlisations etc be?

We would like to understand if the cost of new trunking licenses are worth it and how the links will behave with and without trunking.

 

Thanks for any help.

Contributor
Posts: 66
Registered: ‎12-24-2015

Re: Difference in behaviour between seperate ISL and ISL trunks

Hi, then you use ISL connection without trunking, you must remember about dls option.

And a problem with latency at connect, reconnect or disconnect one of several ISL links.

Contributor
Posts: 51
Registered: ‎07-08-2011

Re: Difference in behaviour between seperate ISL and ISL trunks

Hi Jim,

 

Please refer this useful document.

 

https://www.brocade.com/content/dam/common/documents/content-types/datasheet/isl-trunking-ds.pdf

 

 

With Regards,

Felix Benadis.

Frequent Contributor
Posts: 130
Registered: ‎02-05-2014

Re: Difference in behaviour between seperate ISL and ISL trunks

The most important part for me has always been the impact on the fabric when a link goes offline. If you have 4 isolated ISL's a link-drop has an immediate effect on fabric operations as FSPF routes have to be recaculated. If a trunk-member link fails there is only a re-balance of traffic on the ASIC driver level but does not impact fabric behaviour as such.

 

I would use trunks if I where you.

Kind regards,
Erwin van Londen
Brocade Distinguished Architect
http://www.erwinvanlonden.net The Fibre Channel blog


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