IEEE 802.11s
From Wikipedia, the free encyclopedia
IEEE 802.11s is a draft IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create an ad-hoc network.
802.11 is a set of IEEE standards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, 802.11g, and 802.11n versions to provide wireless connectivity in the home, office and some commercial establishments.
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[edit] Description
It extends the IEEE 802.11 MAC standard by defining an architecture and protocol that support both broadcast/multicast and unicast delivery using "radio-aware metrics over self-configuring multi-hop topologies."
[edit] Timeline
802.11s started as a Study Group of IEEE 802.11 in September 2003. It became a Task Group in July 2004. A call for proposals was issued in May 2005, which resulted in the submission of 15 proposals submitted to a vote in July 2005. After a series of eliminations and mergers, the proposals dwindled to two (the "SEE-Mesh" and "Wi-Mesh" proposals), which became a joint proposal in January 2006. This merged proposal was accepted as draft D0.01 after a unanimous confirmation vote in March 2006.
The draft evolved through informal comment resolution until it was submitted for a Letter Ballot in November 2006 as Draft D1.00. As of September 2008 the draft is at D2.00. Draft D2.00 failed to reach approval through a Letter Ballot on September 18th with approximately 61% approval. Letter Ballots must reach the necessary 75% approval to pass.
The Task Groups stated goal for the May 2009 802.11 meeting is to start resolving comments from its new Letter Ballot.
[edit] 802.11 mesh architecture
An 802.11s mesh network device is labelled as Mesh Station (mesh STA). Mesh STAs form mesh links with one another, over which mesh paths can be established using a routing protocol. 802.11s defines a default mandatory routing protocol (Hybrid Wireless Mesh Protocol, or HWMP), yet allows vendors to operate using alternate protocols. HWMP is inspired by a combination of AODV (RFC 3561[1] ) and tree-based routing.
Mesh STAs are individual devices using mesh services to communicate with other devices in the network. They can also collocate with 802.11 Access Points (APs) and provide access to the mesh network to 802.11 stations (STAs), which have broad market availability. Also, mesh STAs can collocate with an 802.11 portal that implements the role of a gateway and provides access to one or more non-802.11 networks. In both cases, 802.11s provides a proxy mechanism to provide addressing support for non-mesh 802 devices, allowing for end-points to be cognizant of external addresses.
802.11s also includes mechanisms to provide deterministic network access, congestion control and power save.
[edit] Usage
While still in a preliminary development stage, the 802.11s draft is supported by a wide variety of industry leaders. The One Laptop per Child[2] project uses the 802.11s draft standard for its OLPC XO laptop and OLPC XS school server networking. A reference implementation of the 802.11s draft is available as part of the mac80211 layer in the Linux kernel, starting with version 2.6.26[3].
[edit] References
- ^ "RFC 3561 Ad hoc On-Demand Distance Vector (AODV) Routing". Mobile Ad Hoc Networking Working Group of the Internet Engineering Task Force. July 2003. http://www.ietf.org/rfc/rfc3561.txt. Retrieved on 2007-03-03.
- ^ "One Laptop per Child". http://www.laptop.org. Retrieved on 2007-03-10.
- ^ 2.6.26"Linux 2.6.26 Changes". http://kernelnewbies.org/Linux_2_6_26#head-26b4a3f6eb606c21056e4f906a4dae88077346f5. Retrieved on 2008-07-14.
