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The Customer Across the Street

Members of the ISP-Tech list share a massive but varied list of methods for connecting LANs in two buildings that are across the street from each other.

[August 22, 2002]

On the ISP-Tech list in July, HR queried,

"I have a customer who has two buildings across the street from each other, and he would like to connect the two networks. They have 50 pairs of regular copper going between the buildings: does anyone know of a device that can be plugged into a network to bridge Ethernet over plain copper? I could do it with two routers and CSU/DSUs, but am not sure of the distance issues: it's about 200 meters."

A number of respondents recommended some commercial solutions:

[TB advised] "Check out Net to Net Technologies: they've got exactly what you're looking for."

[JS added] "Try Black Box Network Services: they usually have some interesting and creative products."

[AG offered] "Something like the Patton Model 2158 CopperLink Ethernet Extender should work."

[DJ added] "If you use that, make sure to add Patton's surge protectors."

Others discussed whether or not the distance is likely to be a problem:

[BK offered] "It sounds like you could put a router at each end. Just splice an RJ-45 to each end—but do test the lines first."

[JS warned] "200 meters is out of range for Ethernet by 100 meters—otherwise, you could just connect them. CSU/DSUs should cover the distance, assuming this is Cat-3 or Cat-5 copper."

[RB countered] "Ethernet can do 30 miles over fiber, and thousands of feet over Cat-3. I know of a West Coast CLEC doing 10 megabits on Cat-3 out to 5000 feet."

[BS added] "Keep in mind that single-mode fiber Ethernet can go over a kilometer, and is (comparatively) cheap and easy to implement—as long as you have right-of-way to run the cable."

GS noted that there's one more issue to consider:

"In my experience, if the buildings don't share the same electrical panel and ground, you'll be frying something every time a storm front goes through, since the ground circuit is being completed through your fragile routers. This might be a case for optical isolators on each end of the wires, for expensive silicon avalanche diodes, or for wireless."

—End