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New Member

Fiber connection between two buildings

We are expanding our network into the building next door using fiber. We currently have a Catalyst 5500 with the following modules-

(2) WS-X5530 supervisor modules

(2) WS - FEFX MMF dual port fiber modules

(10) 24 port 10/100 ethernet modules

We are looking replacing the 5500 with a 6509 and placing the 5500 in the new building. What do I need to connect the two switches with fiber? Do I need a fabric module?

Any suggestions, prods in the right direction or pitfalls to avoid would be appreciated.

New Member

Re: Fiber connection between two buildings

In order to connect the 6509 to 5500 using the FEFX Daughter Card on your 5500, you have to make a fiscal decision. That daughter card is End-Of-Sale on the 5500 and the only module for the 6509 that supports 100 Base-FX is part # WS-X6324-100FX-MM which retails for $15,000. I would instead purchase (if you want to stay with using the 5500) part # WS-U5536-GESX or US-U5536-GELX depending on how far your fiber run is between buildings. This will allow you to run GigE between buildings instead of FE. The first part # retails for $4000 and the second one for $6000. You will also need to purchase a SX or LX GBIC for the 6509.

I don't feel that you need the fabric module.

What are you going to be running in the new building (# of clients, type of applications being used, etc...)? Post that info and then I will be more than happy to suggest possible alternatives that may fit your needs better than this.


New Member

Re: Fiber connection between two buildings

The distance between the buildings is 50-100 yards and the distance between the 2 wiring closets will is a guestimated 300 - 500 ft. It's hard to tell until the floor plans are scaled and complete.

There will be about 100 clients in the new location initially with the applications being primarily email, accessing file servers and our in-house developed web applications. The number of clients could grow to 200-250, so the 5500 allows the room for growth in that building.

The thought behind replacing the 5500 in use now is that all of the servers and future servers and storage will be on that switch. GigE for the servers/storage is very possible in the future and the 5500 is limited in it's support of GigE or from what I've read.


Re: Fiber connection between two buildings

Do you already have fiber between the buildings? If so, what kind is it - MMF or SMF? If MMF, is it 62.5-micron or 50-micron?

If fiber is not in place yet, Cisco recommends installing hybrid cable, which has strands of each. Multimode for "legacy" connections (e.g. Ethernet, Token Ring, FDDI, Fast Ethernet, and some Gig Ethernet); and single mode for higher speeds (other Gigabit Ethernet, 10 Gig Ethernet, CWDM, and DWDM).

The best and most elegant solution is to put the Gigabit Ethernet module in the 5500, as Josh outlined in his post. Your end-to-end fiber distance is crucial, because it determines what optics you must use, and that determines how much it will cost.

Besides "line-of-sight" and "as-the-crow-flies" distances, don't forget that fiber installation may be forced to jink this way and that within a building, to take advantage of existing conduit , pathways, raceways, or innerduct, in order to run cable. So your end-to-end distance may be even longer than you think. Best practice is to baseline it with an optical power meter or OTDR to verify the fiber's ability to carry your intended signaling. That being said...

Gigabit-SX can only be expected to push 220 to 275 meters over MMF, but optics are generally less expensive: 1000BASE-SX GBIC lists for $500.

Gigabit-LX standard spec is to 5km, but Cisco optics can reliably push to 10km, over SMF. LX GBICs can also push to 550m over multimode, using mode-conditioning launch patch cables. Increased performance of the optics comes with a price: 1000BASE-LX/LH GBIC lists for $995.

If the Gig module in the 5500 seems not feasible, due to availability, cost, or office politics, here are some other options:

1. Purchase a small stackable switch like a 2950G-24, and two GBICs. Put the 2950G in the building with the 5500, and use the Gig link to tie in to the 6509. Put in four Cat5 crossover cables between the 2950G and the 5500, configure Fast EtherChannel (FEC) across that bundle. Equipment cost: $3,500 to $4,500 list, depending on which GBICs and fiber you have. Patch cables not included in price.

2. If you have MMF, and must go cheap, then purchase up to four Fast Ethernet media converters, 100Base-TX to 100Base-FX, to match up with the 100FX ports you already have on the 5500. Plug the media converters into 10/100 ports on the 6509 or into an access switch directly connected to the 6509. Configure FEC across the four fiber connections. Equipment cost: about $1,400 list , $960 street. Patch cables not included in price.

I agree with Josh, do not buy a 100FX module for your 6509. It costs too much, and delivers too little in your situation to justify the expense. Options (1) and (2) above accomplish the same thing, performance-wise, and don't cost as much.

Hope this helps.