distribution switch,core switch 40 miles apart

[sarahr202]

hi everybody.

Another weird scenario, I hope you guys can help me with that.

( access switch)---trunk----Distribution sw ------distance 40 miles------Core switch      

Our design requires distribution switch should be connected to core switch using ethernet.  Further assume our distribution and core can switch have GBIC/ SMF slots.

My question is how we connect them using ethernet? obviously we can not strech the fiber/copper over 40 miles to connect distribution and core switches.                          

Thanks and have a great weekend.

[Peter Paluch · Accepted solution]

Hi Sarah,

You won't be able to place a single uninterrupted fiber between your distribution and core switch but you surely can create the interconnection from a number of optical fiber segments with optical regenerators (EDFA or similar) placed inbetween. This is how most long-haul optical connections are made. Once this optical path is established, you can carry any Layer2 framing over it, including Ethernet.

Have a look at this page:

http://samon.cvt.stuba.sk/

It is a map of Slovak Academical Network (SANET as we call it - it interconnects all major Slovak cities; Slovak universities and also some other predominantly academical institutions are attached to it). As you can see from this map, this network is built exclusively on Ethernet run over fiber. Of course, the distances are in terms of tens to hundreds of kilometers. Hence, optical signal regenerators have to be used along all longer fiber runs.

The task of planning this optical interconnect should however be given to a company specializing in these solutions. With fiber runs, there are lots of things to consider - not that I am knowledgeable of them, I just saw a tiny fraction of things to consider and I understood that it's a science in its own right.

But the bottom line is - yes, it is possible to make Ethernet interconnection over such a span, it will be a fiber but at least one optical regenerator along the fiber run will be necessary.

Best regards,

Peter

[sarahr202]

Thanks Peter and Leolahoo.

1000 base zx can have 100 km distance.

My question is what 100 km distance means?  Does it it is is max distance we can have between 1000 basezx - based ports? Does it mean  that is the maximum distance we could  have before we need to use optical repeater?

have a great  day.

[Leo Laohoo · Accepted solution]

Bascially you can "shoot" up to 100 km fibre length.

However, this does not mean that you can use ZX to, say, a distance of 1 km because this will "burn" your SFP/GBIC module.

[sarahr202]

Basically you can "shoot" up to 100 km fibre length.

So if we use optical repeater to achieve greater distance than 100km,  will it be violating 1000 base zx standard?

thanks Leolahoo

[Leo Laohoo · Accepted solution]

will it be violating 1000 base zx standard?

Errrr ... Yes.  The laser will not be able to reach that far and you'll probably need an optical generator.

[Leo Laohoo · Accepted solution]

Agree with Peter's post.  In some cases, yes, it's possible.

But your topology has one flaw.  Single fibre optic link between core and distro.  All you need is a fibre-trunk-hunting-excavator and you're day is done.