Breaking the 328 foot barrier

Old 2 Comments on Breaking the 328 foot barrier 21

If you’ve taken any networking courses, you’ve probably been taught that the maximum recommended distance for Cat5e/Cat6 cabling is 100 meters (or 328.084 feet). Alternatives to such a limitation generally include using fiber optic cabling, or a point to point wireless bridge. There is now, a third.

Adtran is a company largely known by Carriers for its CSU/DSU (Channel Service Unit/Data Service Unit) equipment, but is little known in SMB circles. In the last decade, while you were trapped in the Cisco walled garden, they have been making switches, routers, and business phone systems. I use these almost exclusively when building systems for our customers. Recently, a customer, who we had just implemented a phone system and network infrastructure for, expressed the need to add an office/small building to the network that was located across its parking lot approximately 800 feet away.

The request was simple, add the building to the network, so they can ditch the Time Warner circuit that connected to the main building via site to site VPN. With this charge, we could then propagate DHCP and VLANs from the main site so that VoIP system could be extended without much fuss.  The solution, at first, was not so simple. Our starting point was an existing (privately owned) 25 pair aerial telephone cable connecting the two sites. Two of the 25 pair were used to deliver analog phone service to the smaller building. The customer wasn’t interested in placing fiber on the aerial span, nor where they interested in purchasing wireless antennas and supporting equipment. Enter Adtran’s ActivReach.  Adtran recently introduced Broadcom’s BroadReach technology into their 1500 series switches, naming it respectively ActivReach. This technology allows you to extend a 10/100 Ethernet connection up to 1,600 feet utilizing cable grade as low as Cat3 using 4 pair. The technology is similar to xDSL, but at higher frequencies. Also, interestingly enough, a single pair of Cat3 can get you as far as 600 feet.  What’s more amazing is that this can also deliver PoE/PoE+ to endpoints like phones and IP cameras. 

ActivReach’s capabilities:

Thanks to Adtran, our solution was simple. The plan was to use 4 unused pair of the existing 25 to create a 100 Mbps connection between the two sites. This was slightly faster than the 15 Mbps Time Warner circuit.  A fresh piece of Cat5e was run from one of the network IDFs  at the main site to the 25 pair entrance and 4 pair were spliced to the cable. On the other side, another section of Cat5e was spliced to the cable, and run to the location of the new Adtran Netvanta 1535P with ActivReach. Each side of the Cat5e was terminated with an RJ-45 connector using the ANSI/TIA/EIA-568-B standard. The ActivReach connection was terminated on the side of the main site with an Adtran ActivReach media converter which then plugged into an already existing switch. 

After enabling ActivReach on the particular 1535 port I was using, the connection came up immediately, reading 100Mbps. Well, that was easy! Speed tests, packet loss and jitter evaluations all were more than acceptable. If you have a need to reach beyond 328 feet, or simply utilize old cabling to deliver 10/100 Mbps connections with PoE, you might want to give Adtran a look.

Author

Marc Spehalski

Marc Spehalski holds a B.S. in Computer Information Systems, and is a U.S. Air Force and OIF veteran specializing in ICBM communications networks. Marc's background is in electronics, telecommunications, and network infrastructure.

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2 Comments

  1. Martin Lehner June 20, 2014 at 11:09 pm

    Very very cool. I knew these products were out there, but didn’t know much else about them. I wish they would get a bit more mainstream, as they’re still out of price reach for small organizations that might otherwise greatly benefit from them.

    • Marc Spehalski June 22, 2014 at 7:16 pm

      Their products are priced appropriately (relatively) in my opinion, but their product line doesn’t really cater to smaller organizations. There are rumors that Adtran is working on a striped down version of their NetVanta 7100 (IP PBX) that eliminates the router, and PoE switch components for more aggressive pricing. I’m really looking forward to this as it’s difficult to sell a $4,000 PBX/Switch/Router to a small family medical practice. They are losing that customer base to hosted phone systems.

      Adtran has however recently released the NetVanta 1531P which is a 10 port managed Layer2/3 lite PoE Gig switch for around $500.

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