Choosing Fibre cable

[mahesh18]

           Hi Everyone,

From Fibre Patch Panel to switch which is around 6 feets away which cable should we use Single mode  or Multi Mode?

I read that Multimode is used for shorter distances and can carry more data.

Or does it depend on type of GBIC which we use on switch side?

Office A side is

Switch  module is side is 18  1000BaseX (GBIC)                       WS-X4418-GB   

Gbic on port is 

Type:                  1000BaseSX

Office B  end switch port is

Type:                  1000BaseSX SFP

Both office is connected with fibre within  same building.

Thanks

Mahesh

[Collin Clark · Accepted solution]

It is dependant on the GBIC/SFP. The 1000BaseSX is a multi-mode fiber GBIC so you should purchase multi-mode fiber.

As a side note - Single-mode fiber can travel further than multi-mode. Depending on the distance and core size of the fiber determines the amount of bandwidth in can carry and how far it can carry it.

Hope it helps;

[mahesh18]

Hi Collin,

Thanks for your reply.

We are using on Office A

Patch to switch Multi mode

Office B

Patch to Switch Single mode

Do you  know if this could cause the performance as we are using  both SM  and MM  ?

Thanks

Mahesh

[Collin Clark]

Yes it can. Is it multi-mode or single-mode fiber between Office A and Office B?

[mahesh18]

Hi Collin,

Between 2 offices it is Multimode.

What type  of performance issue it could cause?

Thanks

MAhesh

[Collin Clark · Accepted solution]

slow speeds, packet loss, etc Take a look at your interface counters and see if there are a large number of errors.

[mahesh18]

Hi Collin,

I did sh int , sh int counters errors   there were no errors on the interface which has single mode fibre.

Thanks

MAhesh

[Collin Clark]

Please check both ends. There may not be any errors, but using two different types of fiber may cause problems.

[mahesh18]

Hi Collin,

I checked at interface which has MM  cable found

31 symbol errors found. Symbol error frames are the errors that occur

due to misalignment of encoding at layer 1 31 symbol errors found. Symbol error frames are the errors that occur
due to misalignment of encoding at layer 1.

Do you think it can be due to SM  cable used at other end?

Thanks

MAhesh

[Collin Clark]

Symbol errors are typically caused by a bad cable or GBIC. 31 errors is not excesive. How long have the interfaces been up and passing traffic?

[mahesh18]

Hi Collin,

Sorry for last  post it was from different  interface.

That interface has no errors.

Interface connected to SM  i found output drops and as per cisco website they are less than .3 %.

Thats all i found on both sides .

So seems as per you i  should change cable from SM  to MM  right?

Thanks

MAhesh

[Collin Clark]

Are you experiencing any problems?

[mahesh18]

No problems curently.

Only thing is that  other offices have MM  cable all the way to main office.

Only this office has SM cable.

[Collin Clark · Accepted solution]

If you're not experiencing any issues then there probably isn't a reason to change it right now. For consistency you may want to swap it out.

[mahesh18]

Hi Collin,

May thanks for all your replies in timely manner.

Regards

Mahesh