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Occasional Contributor
Posts: 16
Registered: ‎02-23-2015
Accepted Solution

CONFIRMATION NEEDED: How to "Change ISL SFPs and configurations" for Brocade 300 SAN Switch Farbics with 2 ISL each

[ Edited ]

Hi all

 

I am sorry to ask you about this topic but I am really not sure anymore and at a rush.

 

We do have 2 Brocade 300 SAN Switches. Each Farbic is connected by 2x ISL based on 4 Gbits SFP modules. On these switches we do have different kind of hardware and different speed configurations (2gbit, 4gbit, 8 gbit). Now we want to replace the 4 Gbit ISL SFPs with 8 Gbit one because we see a high load on these.

 

Can you give me an answer to the following question:

1) As far as I can remeber ALL ISL connections have to be configured the same speed as the slowest ISL connection, right?
2) It is not problem to have different speed confiugration for the end devices and to run all the ISL connections with 8Gbit, right?
3) To benefit the most we would need to update the SFPs to 8 gbit for all end devices unless this is supported by the end devices, right?
4) Can I replace ONE 4gbit ISL SFP in a Fabric with 2 ISL connections to replace it with a 8 Gbit and after that the other one WITHOUT any downtime? How long do I have to wait before changing the 2nd?

 

Thas is basically it.

 

One additional question. During the assesment this morning I saw that only one of the ISL per Fabric seem to be active (upstream, downteam) can I just unplug these modules anyway and it will failover seemless to the other link OR do I need to failover manually first to the other ISL link? Would we need to have ISL trunking in the future to have live failover and load balancing capabilties or is this only for bandwith aggregation?

 

Thank you very much and have a great day!

Regular Contributor
Posts: 208
Registered: ‎04-04-2018

Re: CONFIRMATION NEEDED: How to "Change ISL SFPs and configurations" for Brocade 300 SAN Switch Farbics with 2 ISL each

Hello 

1) As far as I can remeber ALL ISL connections have to be configured the same speed as the slowest ISL connection, right?

 

Its better to keep all ISL on same speed level because of bottlenecks.

 

Brocade switches are using FSPF (Fabric Shortest Path First) where it will detect shortes route for traffic based on link cost.

Link cost for 4Gb and 8Gb is 500 which means that the switch will use both ISL as equal.

 

 


2) It is not problem to have different speed confiugration for the end devices and to run all the ISL connections with 8Gbit, right?

 

No it's not problem. Of courste if you have 8Gb devices going via 4Gb ISL you will have bottleneck on ISL.

 


3) To benefit the most we would need to update the SFPs to 8 gbit for all end devices unless this is supported by the end devices, right?

 

Yes, if you would like to get max. from your fabric you have to upgrade your end devices.


4) Can I replace ONE 4gbit ISL SFP in a Fabric with 2 ISL connections to replace it with a 8 Gbit and after that the other one WITHOUT any downtime? How long do I have to wait before changing the 2nd?

 

You may configure new ISL and ther decomission old one.

Its better to verify multipathing on your devices first.

 

During the assesment this morning I saw that only one of the ISL per Fabric seem to be active (upstream, downteam) can I just unplug these modules anyway and it will failover seemless to the other link OR do I need to failover manually first to the other ISL link?

 

Its based on your routing settings if you have Exchange based without IOD there is No Frame loss (Please refer to admin guide for more details)

 

Would we need to have ISL trunking in the future to have live failover and load balancing capabilties or is this only for bandwith aggregation?

 

Its true the trunking is merge link to perform bandwith aggrgation. Second thing is that it uses masterless trunking which means that if the master port goes offline another slave port will come online with old PID of master so the trafic is not interrupted.

 

 

Please mark this response as "Accept as Solution" if it answers your question.

Marian Bezeg
Occasional Contributor
Posts: 16
Registered: ‎02-23-2015

Re: CONFIRMATION NEEDED: How to "Change ISL SFPs and configurations" for Brocade 300 SAN Switch Farbics with 2 ISL each

[ Edited ]

Hi Marian

 

Thank you very much for yuor feedback.

 

1)

Do I get that right, that even WITHOUT the trunking license I can have a seemsless faiover with 2 ISL connections when I do have "Exchange based without IOD"? OR is this only available when I got the trunking license?

 

Can you point me to a document or GUI / CLI point where I can check this configuration?

 

2)

Is it also true that I have to manually failover to the the 2nd ISL link first before replacing the modules in ISL link 1 and vice versa if I do NOT have "Exchange based without IOD" otherwise I will face downtime?

 

If so, can you point me to an according document?

 

Here I do have a snippet of the SWITCH Configs

 

--BEGIN SWITCH
DLS=1
IOD=0
Lossless=0
isStaticRouteSupported=2
dlsConfigSupported=0
isLosslessDLSSupported=1
aptpolicy=3
--END SWITCH

 

I really appreciate your help

 

Regular Contributor
Posts: 208
Registered: ‎04-04-2018

Re: CONFIRMATION NEEDED: How to "Change ISL SFPs and configurations" for Brocade 300 SAN Switch Farbics with 2 ISL each

ello,

 

so from your output aptpolicy = 3 which means that you are running Exchange Based Routing Policy.

 

1: Port Based Routing Policy
2: Device Based Routing Policy (FICON support only)
3: Exchange Based Routing Policy

 

In Fabric OS Administrator's Guide v7.4 on page you can see all info about Exchange routing.

Because of that Exchange is activated, DLS is automatically enabled as its mandatory for this policy.

DLS is automatically loose less enabled so you will not occure Frame loss,(the out of order delivery may occure for affected exchange)

 

 

Because of that the recommendation is to perform any action on ISL during quite time (out of bussiness hours).

 

If you will have at least one ISL online (active) between switches, the action will be online.

I really dont understand your question about failover. At least you should have there redundant SAN fabric in any case.

 

I recommend to build up new ISL and then disconnect old one. Or if you have 2 ISL between switches you may portdecomm first change speed or SFP and bring it back online after that you may do it in simmilar way on second link.

 

With trunking license you will be able to manage multiple ISL links as one logical link. The benefit of failover is that trunk is using masterless so it will be able to disable another member of ISL without interuption.

 

 

Please mark this response as "Accept as Solution" if it answers your question.

Marian Bezeg
Highlighted
Occasional Contributor
Posts: 16
Registered: ‎02-23-2015

Re: CONFIRMATION NEEDED: How to "Change ISL SFPs and configurations" for Brocade 300 SAN Switch Farbics with 2 ISL each

Great and valuable feedback, thanks a lot! :-)

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