Fibre/Switch questions

Bakedgoods

Bakedgoods

Bakedgoods

Capodecina
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What precuations and measures should be taken when there is a fibre line running near a lake? Sheilding etc? Is this generally expensive?

If i'm laying a fibre cable 800m long should I opt for single mode? It's a simple link between switches on a relatively small network so only two cores should be needed (as I understand it, one for send and one for receive?).

Can anyone recommend any Cisco switches that support both multimode and single mode fibre connections and have 24 standard ethernet ports?

Thanks for any help :)
 
I'm sorry but no :P

I've tried googling for information about sheilding and common practices but I was hoping someone had real world experience.
 
Well are you planning on having it underground or tied along to a wall or some other surface? if underground its best to have it contained in copex which is plastic tubing and if you are say running it along a surface then fibre can be simply tied out of the way, Its not expensive.

Do they have to be cisco switches?

Im a network infrastructure engineer as for the real world experience.
 
Thanks!

It's not essential but preferable since they are pretty much standard as i'm sure you're well aware.

The fibre will run underground. Can't decide if I should use single or multimode, I originally thought single but i'm unsure if there's a need.

- Retarded question here, but what are the little media converter fibre ports you can place into a switch so you can connect fibre to it called?
 
Any cisco switch which takes Gbic or SFP modules (virtually all except the very base models) will be able to use multi and single mode fibre via the appropriate modules. Any Cisco 2960 with SFP slots would likely suit you.

As for the fibre I couldn't tell you, all ours is either done by specialists or pulled through existing ducting. Generally we always use at least 12 core cable, for future expansion and give you an option if one pair stops working (not unheard of)

EDIT: I'd definately go for single mode, i've only user used multimode within datacenters as a rule. Slightly more expensive in terms of SFPs and Gbics though...
 
I thought that would be the best option thanks.

I'll be using multimode for linking any switches that are in the same cabinet/close proximity though.

There isn't really any need for the bandwidth that 12 core would give (I am right in thinking 6 send, 6 receive yes?). I'll need to start thinking about using fibre panels if I use that many cores won't I?

The reason I say that is because I don't want to have to use a completely different switch just for fibre.

The fibre link i'm talking about will be from a distribution switch to a core switch.

All the links (switch to switch in same cabinet, switch to router, router to router) will be done using multimode, any over long distance (outside) will be using single mode.

Does that make sense?

Thanks for your help
 
Wardie said:
I thought that would be the best option thanks.

I'll be using multimode for linking any switches that are in the same cabinet/close proximity though.

There isn't really any need for the bandwidth that 12 core would give (I am right in thinking 6 send, 6 receive yes?). I'll need to start thinking about using fibre panels if I use that many cores won't I?

The reason I say that is because I don't want to have to use a completely different switch just for fibre.

The fibre link i'm talking about will be from a distribution switch to a core switch.

All the links (switch to switch in same cabinet, switch to router, router to router) will be done using multimode, any over long distance (outside) will be using single mode.

Does that make sense?

Thanks for your help
Click to expand...

makes perfect sense...

typically I'd always terminate the fibre run in a patch panel and then cross patch from there to the switch. I don't know if you'll get a toughened 2 core fibre...something like this would likely do the job though I'd still be tempted to pull it through some tubing of some kind for extra protection...

http://rswww.com/cgi-bin/bv/rswww/s...cckaddmkdlgeflcefeceeldgondhgf.0&cacheID=ukie

bear in mind that terminating fibre (polishing etc) isn't for beginners so you may want to get somebody to do that part for you or buy a pre terminated cable.

for core to distribution switches you might be looking at router rather than switched links, so a 3560 or 3750 might be a better option....if you're linking a core and node building i'd definately lay two fibre pairs at least, run etherchannel or spanning tree or something, the small additional cost is well worth the redundency...
 
If you use a fibre patch panel and say have an 8 core single mode going into it, when you patch to the switch it will require you to use 8 patch panel ports and 8 ports on the switch yes?

I'm guessing from patch panel to switch I would use multimode rather than single mode though? So it would be single mode outside through some ducts into a patch panel, then multimode from PP to switch?

I don't suppose you have any sites I can reference for the bandwidth you get from using say 4 cores, 6 cores etc. I'm struggling :/

If I show you my topology diagram will that help? I'm new to this and only learning so it's all very appreciated.
 
Wardie said:
If you use a fibre patch panel and say have an 8 core single mode going into it, when you patch to the switch it will require you to use 8 patch panel ports and 8 ports on the switch yes?

I'm guessing from patch panel to switch I would use multimode rather than single mode though? So it would be single mode outside through some ducts into a patch panel, then multimode from PP to switch?

I don't suppose you have any sites I can reference for the bandwidth you get from using say 4 cores, 6 cores etc. I'm struggling :/

If I show you my topology diagram will that help? I'm new to this and only learning so it's all very appreciated.
Click to expand...

You can run the fibre into the patch panel and just use the first pair today, doesn't matter if the other 6 pairs sit there doing nothing for a couple of years! So you only need as many switch ports as you choose to use.

Possibly the best example I could give is we have a 24 core cable between a couple of our datacenters in docklands, so 12 pairs, we don't need all of them, so we rent some out to other companies. They just plug their own kit directly in and it doesn't interfere with ours at all.

Fibre needs to be the same all the way from one transciever to another, so single mode through the ducting or underground) and single mode from the match panel to the gbic/SFP.

For bandwidth, you'll get 1Gbit/s times the number of fibre pairs you use. So if you run etherchannel over 4 fibre pairs, (or 8 fibre cores) then you'll get max 4Gbit/s full duplex. (assuming 1Gbit interfaces)

Topology diagram might help if you have one handy.
 
bigredshark said:
makes perfect sense...

typically I'd always terminate the fibre run in a patch panel and then cross patch from there to the switch.
Click to expand...

Agreed. Much cheaper and easier to replace a fibre patch lead. We also put spare cores in, even if there is no foreseeable use for them at the time of install. It's amazing how you suddenly find uses for them.
 
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