IEEE 802.11s

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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.

Contents

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.

The IEEE 802.11s standard was issued in 2011 and was superseded in 2012 when it became part of the IEEE 802.11 standard that was issued in 2012. [1]

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."

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 [2] to be supported as a default. However, other mesh, ad hoc (Associativity-Based Routing, Zone Routing Protocol, and location based routing) or dynamic link-state routing (OLSR, B.A.T.M.A.N. [ citation needed ], 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 of mesh security below.

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. [3]

The 2012 release of the 802.11 specification (802.11-2012) [4] directly incorporates Mesh Routing functionality.

A wireless mesh network architecture allowing otherwise out-of-range nodes 1-4 to still connect to the Internet. A key characteristic is the presence of multiple-hop links and using intermediate nodes to relay packets for others. XO internet access.jpg
A wireless mesh network architecture allowing otherwise out-of-range nodes 1–4 to still connect to the Internet. A key characteristic is the presence of multiple-hop links and using intermediate nodes to relay packets for others.

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.

Routing protocols

802.11s defines a default mandatory routing protocol (Hybrid Wireless Mesh Protocol, or HWMP), [2] yet allows vendors to operate using alternate routing protocols. HWMP is inspired by a combination of AODV (RFC 3561 [5] ), which uses on-demand ad hoc routing approach and tree-based routing. Examples of on-demand ad hoc routing are Dynamic Source Routing and Associativity-Based Routing. AODV route discovery and localized route repair approaches are identical to Associativity-based Routing. Prior work [6] [7] [8] [9] has discussed and compared these various routing protocols in detail. [10]

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, a framework for congestion control and power save.

Mesh security

There are no defined roles in a mesh –no clients and servers, no initiators and responders. Security protocols used in a mesh must, therefore, be true peer-to-peer protocols where either side can initiate to the other or both sides can initiate simultaneously.

Peer authentication methods

Between peers, 802.11s defines the secure password-based authentication and key establishment protocol Simultaneous Authentication of Equals (SAE). SAE is based on Diffie–Hellman key exchange using finite cyclic groups which can be a primary cyclic group or an elliptic curve. [11] The problem with a Diffie–Hellman key exchange is that it does not have an authentication mechanism. So the resulting key is influenced by a pre-shared key and the MAC addresses of both peers to solve the authentication problem.

When peers discover each other (and security is enabled) they take part in an SAE exchange. If SAE completes successfully, each peer knows the other party possesses the mesh password and, as a by-product of the SAE exchange, the two peers establish a cryptographically strong key. This key is used with the "Authenticated Mesh Peering Exchange" (AMPE) to establish a secure peering and derive a session key to protect mesh traffic, including routing traffic.

Implementations

The IEEE 802.11s amendment is supported by many products such as open80211s, OLPC. [12] In open80211s smaller meshes of under 32 nodes [13] are supported. Some of the projects were based on earlier (draft) versions.

See also

Related Research Articles

IEEE 802.15 is a working group of the Institute of Electrical and Electronics Engineers (IEEE) IEEE 802 standards committee which specifies Wireless Specialty Networks (WSN) standards. The working group was formerly known as Working Group for Wireless Personal Area Networks.

<span class="mw-page-title-main">Wireless LAN</span> Computer network that links devices using wireless communication within a limited area

A wireless LAN (WLAN) is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. This gives users the ability to move around within the area and remain connected to the network. Through a gateway, a WLAN can also provide a connection to the wider Internet.

<span class="mw-page-title-main">Wireless network</span> Computer network not fully connected by cables

A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking allows homes, telecommunications networks and business installations to avoid the costly process of introducing cables into a building, or as a connection between various equipment locations. Admin telecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure.

Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection. Hence, Zigbee is a low-power, low data rate, and close proximity wireless ad hoc network.

<span class="mw-page-title-main">Wireless mesh network</span> Radio nodes organized in a mesh topology

A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.

<span class="mw-page-title-main">Service set (802.11 network)</span> Group of all devices on the same wireless network

In IEEE 802.11 wireless local area networking standards, a service set is a group of wireless network devices which share a service set identifier (SSID)—typically the natural language label that users see as a network name. A service set forms a logical network of nodes operating with shared link-layer networking parameters; they form one logical network segment.

IEEE 802.11i-2004, or 802.11i for short, is an amendment to the original IEEE 802.11, implemented as Wi-Fi Protected Access II (WPA2). The draft standard was ratified on 24 June 2004. This standard specifies security mechanisms for wireless networks, replacing the short Authentication and privacy clause of the original standard with a detailed Security clause. In the process, the amendment deprecated broken Wired Equivalent Privacy (WEP), while it was later incorporated into the published IEEE 802.11-2007 standard.

<span class="mw-page-title-main">Optimized Link State Routing Protocol</span> IP routing protocol optimized for mobile ad hoc networks

The Optimized Link State Routing Protocol (OLSR) is an IP routing protocol optimized for mobile ad hoc networks, which can also be used on other wireless ad hoc networks. OLSR is a proactive link-state routing protocol, which uses hello and topology control (TC) messages to discover and then disseminate link state information throughout the mobile ad hoc network. Individual nodes use this topology information to compute next hop destinations for all nodes in the network using shortest hop forwarding paths.

Ad hoc On-Demand Distance Vector (AODV) Routing is a routing protocol for mobile ad hoc networks (MANETs) and other wireless ad hoc networks. It was jointly developed by Charles Perkins and Elizabeth Royer and was first published in the ACM 2nd IEEE Workshop on Mobile Computing Systems and Applications in February 1999.

IEEE 802.11r-2008 or fast BSS transition (FT), is an amendment to the IEEE 802.11 standard to permit continuous connectivity aboard wireless devices in motion, with fast and secure client transitions from one Basic Service Set to another performed in a nearly seamless manner. It was published on July 15, 2008. IEEE 802.11r-2008 was rolled up into 802.11-2012. The terms handoff and roaming are often used, although 802.11 transition is not a true handoff/roaming process in the cellular sense, where the process is coordinated by the base station and is generally uninterrupted.

<span class="mw-page-title-main">Wireless network interface controller</span> Hardware component that connects a computer to a wireless computer network

A wireless network interface controller (WNIC) is a network interface controller which connects to a wireless network, such as Wi-Fi, Bluetooth, or LTE (4G) or 5G rather than a wired network, such as an Ethernet network. A WNIC, just like other NICs, works on the layers 1 and 2 of the OSI model and uses an antenna to communicate via radio waves.

Extensible Authentication Protocol (EAP) is an authentication framework frequently used in network and internet connections. It is defined in RFC 3748, which made RFC 2284 obsolete, and is updated by RFC 5247. EAP is an authentication framework for providing the transport and usage of material and parameters generated by EAP methods. There are many methods defined by RFCs, and a number of vendor-specific methods and new proposals exist. EAP is not a wire protocol; instead it only defines the information from the interface and the formats. Each protocol that uses EAP defines a way to encapsulate by the user EAP messages within that protocol's messages.

The IEEE 802.21 refers to Media Independent Handoff (MIH) and is an IEEE standard published in 2008. The standard supports algorithms enabling seamless handover between wired and wireless networks of the same type as well as handover between different wired and wireless network types also called Media independent handover (MIH) or vertical handover. The vertical handover was first introduced by Mark Stemn and Randy Katz at U C Berkeley. The standard provides information to allow handing over to and from wired 802.3 networks to wireless 802.11, 802.15, 802.16, 3GPP and 3GPP2 networks through different handover mechanisms.

<span class="mw-page-title-main">Wireless security</span> Aspect of wireless networks

Wireless security is the prevention of unauthorized access or damage to computers or data using wireless networks, which include Wi-Fi networks. The term may also refer to the protection of the wireless network itself from adversaries seeking to damage the confidentiality, integrity, or availability of the network. The most common type is Wi-Fi security, which includes Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA). WEP is an old IEEE 802.11 standard from 1997. It is a notoriously weak security standard: the password it uses can often be cracked in a few minutes with a basic laptop computer and widely available software tools. WEP was superseded in 2003 by WPA, a quick alternative at the time to improve security over WEP. The current standard is WPA2; some hardware cannot support WPA2 without firmware upgrade or replacement. WPA2 uses an encryption device that encrypts the network with a 256-bit key; the longer key length improves security over WEP. Enterprises often enforce security using a certificate-based system to authenticate the connecting device, following the standard 802.11X.

IEEE 802.11u-2011 is an amendment to the IEEE 802.11-2007 standard to add features that improve interworking with external networks.

A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers or wireless access points. Instead, each node participates in routing by forwarding data for other nodes. The determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use.

<span class="mw-page-title-main">B.A.T.M.A.N.</span> Routing protocol for multi-hop mobile ad hoc networks

The Better Approach to Mobile Ad-hoc Networking (B.A.T.M.A.N.) is a routing protocol for multi-hop mobile ad hoc networks which is under development by the German "Freifunk" community and intended to replace the Optimized Link State Routing Protocol (OLSR).

The Hybrid Wireless Mesh Protocol (HWMP), part of IEEE 802.11s, is a basic routing protocol for a wireless mesh network. It is based on AODV and tree-based routing. It relies on a Peer Link Management protocol by which each Mesh Point discovers and tracks neighboring nodes. If any of these are connected to a wired backhaul, there is no need for HWMP, which selects paths from those assembled by compiling all mesh point peers into one composite map.

In cryptography, Simultaneous Authentication of Equals (SAE) is a password-based authentication and password-authenticated key agreement method.

References

  1. ↑ Stanley, Dorothy. "Quick Guide to IEEE 802.11 Activities". IEEE . Retrieved 2021-06-30.
  2. 1 2 "HWMP Protocol specification". The Working Group for WLAN Standards of the Institute of Electrical and Electronics Engineers. November 2006. Retrieved 2009-05-03.
  3. ↑ "IEEE P802.11 - TASK GROUP S - MEETINGS UPDATE" . Retrieved 2012-01-02.
  4. ↑ "2012 release of the 802.11 specification (802.11-2012)". Archived from the original on 2018-08-05. Retrieved 2015-08-03.
  5. ↑ "RFC 3561 Ad hoc On-Demand Distance Vector (AODV) Routing". Mobile Ad Hoc Networking Working Group of the Internet Engineering Task Force. July 2003. Retrieved 2007-03-03.
  6. ↑ "A Simulation Study of Table-Driven and On-Demand Routing Protocols for Mobile Ad Hoc Network - S J Lee, et. al., 1999" (PDF). doi:10.1109/65.777441. S2CID   12848559. Archived from the original (PDF) on 2017-09-04.{{cite journal}}: Cite journal requires |journal= (help)
  7. ↑ "Performance Comparison of AODV, TODV, OLSR and ABR using OPNET - E. Nehra & J. Singh" (PDF).
  8. ↑ "Compare the Performance of the Two Prominent Routing Protocols for Mobile Ad-hoc Networks". CiteSeerX   10.1.1.301.6049 .{{cite journal}}: Cite journal requires |journal= (help)
  9. ↑ "A Review of Current Routing Protocols for Ad Hoc Mobile Wireless Networks, 1999" (PDF).
  10. ↑ "Routing Protocols for Ad Hoc Mobile Wireless Networks by Padmini Misra".
  11. ↑ Harkins, Dan (2008). "Simultaneous Authentication of Equals: A Secure, Password-Based Key Exchange for Mesh Networks". 2008 Second International Conference on Sensor Technologies and Applications (Sensorcomm 2008). pp. 839–844. doi:10.1109/SENSORCOMM.2008.131. ISBN   978-0-7695-3330-8. S2CID   18401678.
  12. ↑ "IEEE 802.11s: The WLAN Mesh Standard". academia.edu. Retrieved 2 March 2018.
  13. ↑ Chun-Yeow. "What is the maximum number of nodes supported by Mesh?". Github Issue 62. Retrieved 2 March 2018.
  14. ↑ "Linux 2.6.26 Changes" . Retrieved 2008-07-14.
  15. ↑ "802.11s". Linux Wireless.
  16. ↑ "Mesh/OpenWRT" . Retrieved 2014-07-31.
  17. ↑ BattleMesh contributors. "BattleMeshV7" . Retrieved 2014-07-31.{{cite web}}: |author= has generic name (help)
  18. ↑ "WifiMesh".
  19. ↑ "Making a 'mesh' of your Wi-Fi". 15 November 2016. Retrieved 2016-11-16.
  20. ↑ "MeshPoint.One technical specification" . Retrieved 2019-08-11.
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