Linking physically close sites

[foxpro]

I have three sites, approximately 70 users total, that are across a street from each other, one on 1 side two on the other. I would like to purchase one T-1 connection to support all three sites rather then three separate frac T-1's and the additional HW that requires. All three buildings are the exact same height and have clear line of site. I was wondering if dishes on their roofs could be used to connect to a single T-1. Does anyone know of such a solution or other perhaps better idea?

TIA

[markvtran]

T1 is from 1 Source to 1 Destination. Unless you combine the two buildings that are on the same side Via a LAN and connects to the third via T1. I don't see how you can do it. My suggestion is just run Fiber between the three buildings. You get at least 100 times the speed in addition to no monthly bill. Wireless technology should also taken into consideration since the building are in clear line of site.

[ryan.hicks]

Pay the upfront cost and go wireless or fiber. The wireless way can get 10 times the speed and the fiber 1000 times the speed. This will kill the monthly recurring costs with the T-1 providers as well.

If you can run the fiber, you can purchase 3 catalyst 3524 XL switches and 4 multi-mode GBICS. Wireless - Cisco Aironet ethernet bridges with antennas on the roof.

[mbjohnson]

If you have fiber available to connect the buildings, that would be the best choice. If not I would go with a Cisco Aironet solution. I have hooked up a few buildingd together that way and it works awesome!

Good luck.

[watashiwa]

You might try somthing like,

Installing OpenBSD 3.0 on 3 inexpensive pentium based pc's. Get 3 Aironet Communication 4500/4800 IEEE 802.11DS wireless network adapters.

check this out:

Wireless Networking Overview,

http://www.cisco.com/warp/public/cc/pd/witc/ao340ap/prodlit/airo_ov.htm

OpenBSD kernel based Cisco Aironet wireless adaptor drivers

http://www.openbsd.org/cgi-bin/man.cgi?query=an&apropos=0&sektion=4&manpath=OpenBSD+Current&arch=i386&format=html

OpenBSD wireless network driver,

http://www.openbsd.org/cgi-bin/man.cgi?query=wi&sektion=4&apropos=0&manpath=OpenBSD+Current

the OpenBSD bridge interface.

http://www.openbsd.org/cgi-bin/man.cgi?query=bridge&apropos=0&sektion=4&manpath=OpenBSD+Current&arch=i386&format=html

Use the brconfig utility to bridge the wlan and the lan.

A setup similar to that that should most definately give you faster network throughput, better reliability than the phone company, and more independece. it should also have a lower cost of installation and reoccuring fees.

if you search for wireless networking for some models you can find instructions on building custom antennas which let you do neat stuff. here's one that i liked.

http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

[cisco_login]

Just a quick question on Aironet since two people have mentioned it.

"All Cisco Aironet 350 Series client adapters and access points are IEEE 802.11b compliant*"

Does this mean they are susceptible to the classic arp cache poisoning man-in-the-middle attack?

Also do they use WEP? If so is it not possible for someone to sit out side your office sniffing for about 5 minutes and presto they've worked out how to decrypt your data?

This is a little off topic perhaps but must be a consideration.

[mbjohnson]

I believe they do run WEP, and you specify the shared key to be changed every x minutes.

[tejinashi]

Also do they use WEP? If so is it not possible for someone to sit out side your office sniffing for about 5 minutes and presto they've worked out how to decrypt your data?

Not if they're all assigned a new key every 4:59 seconds.