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Occasional Contributor
Posts: 18
Registered: ‎06-25-2013
Accepted Solution

Long distance trunking

Hi I have two different path (20kms and 35kms) to connect to my secondary data center. Currently we are not trunking those link. Current connectivity scenarios is like this In Fabric A , Switch A at primary data center connect to Switch B at secondary data center via two different path which is 20kms and 35kms. We like to trunk these link so 20kms act as master and 35kms as slave so during link failure seamless fail-over happen. So we can have Fabric B with switch A at PDC connect to Switch B SDC via two different path which in this case 35kms as master and 20kms as slave. Is it possible to trunk 20kms and 35kms as one set so 20kms act master for Fabric A and in other trunk set 35kms as master for Fabric B. Recent link failure in 20kms cause 10 sec drop for failover and which made remote copy over fiber channel failed .
Occasional Contributor
Posts: 18
Registered: ‎06-25-2013

Re: Long distance trunking

Look like my request is not possible is there any other option available to have seamless failure between two links. Below is the extract from Fabric OS 7.2 Requirements for trunk groups The following requirements apply to all types of trunking: • The Trunking license must be installed on every switch that participates in trunking. • All of the ports in a trunk group must belong to the same port group. • All of the ports in a trunk group must be running at the same speed. • All of the ports in a trunk group must be configured for the same distance. • All of the ports in a trunk group must have the same encryption, compression, QoS, and FEC settings. • Trunk groups must be between Brocade switches (or Brocade adapters, in the case of F_Port trunking). Brocade trunking is proprietary and not supported on M-EOS or third-party switches. Trunks operate best when the cable length of each trunked link is roughly equal to the others in the trunk. For optimal performance, no more than 30 meters difference is recommended. Trunks are compatible with both short wavelength (SWL) and long wavelength (LWL) fiber optic cables and transceivers.
Contributor
Posts: 22
Registered: ‎02-24-2014

Re: Long distance trunking

Trunking is designed to turn multiple identical cables into a single ISL. For multiple "cost" links, it's better to have one trunk on the short path, one on the long path, and then adjust the cost of the link so that the only time the long path gets used is if the short one is dead.

Occasional Contributor
Posts: 18
Registered: ‎06-25-2013

Re: Long distance trunking

Thanks for the reply. But our problem is we have Fabric A and B  , each fabric is connected with one long path and one short path so incase one path fails we don't loose connectivity to the fabric.

 

Is there any other solution available without redesigning the path. ?.

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Long distance trunking

sivakumar,

 

first, as be mention by CanadianStorage, in order to create a Trunk, the cable distance should have same leght, by a couple of meter difference is really not a problem, however you have here 15 KM difference....

 

second, show to me both path coming from different carrier or are distributed trough different line resource.

All this make any such Trunking design as not realizable.

 

back to you last question:

 

--->>>Is there any other solution available without redesigning the path. ?.

 

you can try to implement DPS / EBR = Dynamic Path Selection / Exchange Basic Routing, but I'm not sure if this work or not by such a distance.

 

keep in mind, you must disable / set off Trunking feature by the Port in Question on both Switch Side, Local and Remote.

 

 

 

 

 

 

TechHelp24
Contributor
Posts: 22
Registered: ‎02-24-2014

Re: Long distance trunking

[ Edited ]

sivakumar.saravanamuthu wrote:

Thanks for the reply. But our problem is we have Fabric A and B  , each fabric is connected with one long path and one short path so incase one path fails we don't loose connectivity to the fabric.

 

Is there any other solution available without redesigning the path. ?.


In this situation, if you have only one link on each path, you don't use trunking at all. You simply control which link is primary by adjusting the cost of using the linkcost command. 

External Moderator
Posts: 4,907
Registered: ‎02-23-2004

Re: Long distance trunking

Canadian,

 

first, sivakumar ask for another solution, and the only one available - however I've a doubt that any such work - is DPS/EBR

 

second, from a Redundance point of view, DPS/EBR is a for Free low cost of Trunking.

 

and Finally, in order to realized any such redundance, Trunking is not mandatory at all , and btw the correct definition of Trunking or the goal to create a Trunk consist to Bundle TWO or More Port/Path

 

 

TechHelp24
Regular Contributor
Posts: 164
Registered: ‎05-11-2011

Re: Long distance trunking

Hi Sivakumar,

 

there is an Option.

Perform D_Port Test on the longer Link and write down the real distance.

Then Perform D_Port Test on shorter link and write down the real distance.

 

Now buy a SMF with a length of the difference of the two meaurements and wrap it on a spool.

Then insert it in the shortest Path.

 

Thats it !!

 

 

 

Kind Regards
Ralf
Occasional Contributor
Posts: 18
Registered: ‎06-25-2013

Re: Long distance trunking

Thanks Ralf. Now ball is on management court for decesion making to invest extra 30,000 dollars.

 

 

Thanks everyone for helping me.

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