IEEE 802.11s-Cedar Herald Index

IEEE 802.11s is a wireless local area network (WLAN) standard and an IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create a wireless LAN mesh network, which may be used for relatively fixed (not mobile) topologies and wireless ad hoc networks. The IEEE 802.11s task group drew upon volunteers from university and industry to provide specifications and possible design solutions for wireless mesh networking. As a standard, the document was iterated and revised many times prior to finalization.

802.11 are a set of IEEE standards that govern wireless networking transmission protocols. They are commonly used today to provide wireless connectivity in the home, office and some commercial establishments.

IEEE 802.11s

The IEEE 802.11s standard was issued in 2011 and was superseded in 2012 when it became part of the IEEE 802.11 standard that was issued in 2012.

IEEE 802.11s

Description

802.11s extends the IEEE 802.11 MAC standard by defining an architecture and protocol that supports both broadcast/multicast and unicast delivery using "radio-aware metrics over self-configuring multi-hop topologies."

IEEE 802.11s

Closely related standards

802.11s inherently depends on one of 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, or 802.11ax to carry the actual traffic. One or more routing protocols suitable to the actual network physical topology are required. 802.11s requires the Hybrid Wireless Mesh Protocol, or HWMP to be supported as a default. However, other mesh, ad hoc (Associativity-Based Routing, Zone Routing Protocol, and location based routing) or dynamically link-state routed (OLSR, B.A.T.M.A.N., OSPF) may be supported or even static routing (WDS). See the more detailed description below comparing these routing protocols.

A mesh often consists of many small nodes. When mobile users or heavy loads are concerned, there will often be a handoff from one base station to another, and not only from 802.11 but from other (GSM, Bluetooth, PCS and other cordless phone) networks. Accordingly, IEEE 802.21, which specifies this handoff between nodes both obeying 802.11s and otherwise, may be required. This is especially likely if a longer-range lower-bandwidth service is deployed to minimize mesh dead zones, e.g. GSM routing based on OpenBTS.

Mesh networking often involves network access by previously unknown parties, especially when a transient visitor population is being served. Thus the accompanying IEEE 802.11u standard will be required by most mesh networks to authenticate these users without pre-registration or any prior offline communication. Pre-standard captive portal approaches are also common. See the more detailed description below of mesh security.

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. Draft D2.00 was submitted in March 2008 which failed with only 61% approval. A year was spent clarifying and pruning until Draft D3.00 was created which reached WG approval with 79% in March 2009.

In June 2011 the fifth recirculation Sponsor Ballot, on TGs Draft 12.0, was closed. The Draft met with 97.2% approval rate.

The 2012 release of the 802.11 specification (802.11-2012) directly incorporates Mesh Routing functionality.

802.11 mesh architecture

An 802.11s wireless mesh network device is labelled as Mesh Station (mesh STA), or simply an ad hoc node. Mesh STAs form mesh links with one another, over which mesh paths can be established using an ad hoc mobile routing protocol. A key aspect of this architecture is the presence of multi-hop wireless links and routing of packets through other nodes towards the destination node.