ITKnowledge Exchange member "Dave L." had a question about backhaul and resident wireless guru Lisa Phifer and other ITKnowledge Exchange members offered their advice. Here is a portion of the conversation.
I am just now getting into designing a wireless internet application for a customer to cover an extremely large international equestrian center.
I'm pretty much self-taught in this field but one thing is bothering me. Some one asked me about "backhaul" and to be frank I don't have a clue what this is or what it means.
To date I've thought all I have to do is set up my wiring closet, connect my authentication server to my first AP, make sure the other AP's have power and set to the correct channel and wala ... we now have the area covered.
So ... what is "backhaul"?
Lisa Phifer WRITES:
In wired networks, backhaul usually refers to the links used to carry traffic from ISP Points of Presence to a central location where traffic is routed onto the public Internet or ISP's backbone network. Similarly, in a large distributed wireless network, backhaul often refers to links that carry traffic from each WLAN site to the Internet or a backbone network. For example:
* If you have a single office covered by several APs, concentrated through a switch or gateway, to a single Internet access link, then the Internet access link is probably what people are asking about when they inquire about your backhaul.
* If you have a multi-site WLAN, where each site is covered by several APs, and WAN links are used to interconnect all sites to a each other or to a central location, then the WAN links form your backhaul network.
Your backhaul can be wired or wireless. For example, remote offices might be connected via satellite, DSL, T-1, Wi-Fi bridges, or a WiMAX wireless mesh (to give name just a few). "Backhaul" just describes the function provided by those links: to haul traffic back from distribution networks to some type of core network.
Margaret Rouse, from Whatis.com WRITES:
Backhaul, a term probably derived from the trucking industry, has several usages in information technology.
1) In satellite communication, backhaul is used to mean getting data to a point from which it can be distributed over a network. For example, to deliver a live television program from Chicago to authorized DirecPC satellite terminals around the country, the video signals would have to be backhauled by some means (by optical fiber cable or by another satellite system) to the Hughes DirecPC facility in Germantown, Maryland. From there, it would be uplinked to the Galaxy IV satellite from which DirecPC users could view the broadcast (receive it in a downlink from the satellite at their individual terminals). Backhauling is also used to get non-live audio and video material to distribution points at the major broadcast news organizations for broadcast in the evening or ongoing news.
2) Manufacturers of network switching equipment use the term to mean "getting data to the network backbone" (which is similar to its use in the satellite communication industry). For example, Ascend uses the term to describe how its MAX 2000 switch can be used to interconnect data from a backhaul T-1 line on which mobile and remote office users are connected to an Internet service provider and the backbone of the Internet.
3) According to books we like, backhauling is sending network data over an out-of-the-way route (including taking it farther than its destination) in order to get the data there sooner or because it costs less. This kind of backhauling involves understanding changing network conditions and economics.
4) Backhauling may sometimes be used to mean the use of the back channel on a bidirectional communications line.
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