Editing Network Based Application Recognition

'''Network Based Application Recognition''' (NBAR)<ref>[https://web.archive.org/web/20050924161229/http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t8/dtnbarad.htm NBAR defined at Cisco website]</ref> is the mechanism used by some [[Cisco]] [[Router (computing)|router]]s and [[Network switch|switches]] to recognize a [[Traffic_flow_(computer_networking)|dataflow]] by inspecting some [[packet (information technology)|packets]] sent.

The [[Computer network|networking]] equipment which uses NBAR does a [[deep packet inspection]] on some of the packets in a dataflow, to determine which traffic category the flow belongs to. Used in conjunction with other features, it may then program the internal [[application-specific integrated circuits]] (ASICs) to handle this flow appropriately. The categorization may be done with [[Application_layer|Open Systems Interconnection (OSI) layer 4]] info, packet content, signaling, and so on but some new applications have made it difficult on purpose to cling to this kind of tagging.<ref>[[BitTorrent protocol encryption|BitTorrent Encryption and Obfuscation]]</ref>

The NBAR approach is useful in dealing with malicious [[software]] using known [[TCP and UDP port|ports]] to fake being "priority traffic", as well as non-standard applications using dynamic ports.<ref>''[http://www.cisco.com/warp/public/63/nbar_acl_codered.shtml Using Network-Based Application Recognition and ACLs] for Blocking the "Code Red" Worm'', Cisco.</ref> That's why NBAR is also known as [[OSI layer 7]] categorization.

On Cisco routers, NBAR is mainly used for [[quality of service]] and [[network security]] purposes.

==References==
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== External links ==
*[http://whitepapers.zdnet.co.uk/0,39025945,60105500p-39000590q,00.htm ''Network Based Application Recognition: RTP Payload Classification''], Cisco.
*[http://www.cisco.com/en/US/products/ps5855/products_configuration_example09186a0080ac3082.shtml ''Block P2P Traffic on a Cisco IOS Router using NBAR Configuration Example''], Cisco.

[[Category:Computer network security]]


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