Fibre Channel (SAN)

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Occasional Contributor
Posts: 11
Registered: ‎03-17-2011

Connecting 2 ISL between core switches

I want to find out if you connect 2 ISL links between Core switches, but have not purchased trunking would both links pass traffic?  We have set up this configuration and it appears that only one link is passing traffic.   Additionally we made sure to use adjacent fiber ports on each of the switches.

We are looking at purchasing trunking with some new core switches in the next month or so.

Does anyone know how we can remove what appears to be a ghost connection (from the port we moved the fiber cable from) in DCFM.  It still shows the port as grayed out when using the connection properties in DCFM and of course the link on the map show in an error condition.  Are switch reboots required to clear this error?

Thanks for any help.

N/A
Posts: 1
Registered: ‎07-27-2010

Re: Connecting 2 ISL between core switches

1) ISL links must work without any trunking license (they establish two independant links between switches). Trunking license is used only to  make trunks - connections consisting of several links, making the fabric able to loose some of these links without recalculating fabric routing tables.

2) To get rid of the grayed out link, you must "confirm" the changes in the fabric through DCFM interface. No switch reboots are required.

Arthur.

Super Contributor
Posts: 635
Registered: ‎04-12-2010

Re: Connecting 2 ISL between core switches

There is no need for a trunking license both links should pass traffic if it is setup correctly.

I would recommend to login to the switchs via SSH session  and check the ports on the CLI.

If you need further help please provide some more information like switch type, FOS code level

and the out put of the commands,

portshow

portcfgshow

porterrshow

of the affected ports which are not working.

Do not reboot the SAN switch.

I hope this helps,

Andreas

Occasional Contributor
Posts: 7
Registered: ‎03-17-2011

Re: Connecting 2 ISL between core switches

Trunking combined two or more physical ISL in to a single logical link and trunking is licensed feature. So as per my understanding you will not be able to use two ISL' s as a trunk.

Regarding the port - You can run portdisable / portenable command and see if port is coming online.

You can run porttest command as well and porttestshow command to see the result of this command.

Run errdump command to get more information about the port state.

Regards

Shiv

Occasional Contributor
Posts: 11
Registered: ‎03-17-2011

Re: Connecting 2 ISL between core switches

I have attached a spreadsheet with the requested information. I've really only given you one side of the switch network, but the other side looks identical.  Included in the spreadsheet are the switch types and firmware specification.   Let me know if you have any questions.

I guess I should tell you we are using the DCFM Performance Graphs to show utilzation on the links.  Nothing shows up on the newly created ISL links.

Thanks.

Super Contributor
Posts: 635
Registered: ‎04-12-2010

Re: Connecting 2 ISL between core switches

Hi,

I assume that no traffic is passed through the link due to the fact how you have connected the devices to the SAN switch.

This cabling and your configured routing policy will affect which ISL will be used.If you will enable trunking both links will be used.

If you connect some server to odd and some to even port numbers this should cause the switch to use both links.

I hope this helps.

Andreas

New Contributor
Posts: 2
Registered: ‎06-24-2010

Re: Connecting 2 ISL between core switches

"2) To get rid of the grayed out link, you must "confirm" the changes in the fabric through DCFM interface. No switch reboots are required."

How do you "confirm" ?

New Contributor
Posts: 2
Registered: ‎06-24-2010

Re: Connecting 2 ISL between core switches

It's okay, found it, you mean't accept changes by right clicking or using the monitor menu.

Thanks.

Regular Contributor
Posts: 201
Registered: ‎11-24-2009

Re: Connecting 2 ISL between core switches

'Confirm' is in the right-click menu and is actually called Monitor > Accept Changes.

Why would you want to interconnect core switches in the first place? In a classic Core-Edge design interconnecting core switches is neither recommended nor useful because data traffic will never be routed via a longer path (Edge-Core-Core-Edge).

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