Network Based Application Recognition: Difference between revisions

Revision as of 21:07, 19 December 2007

Revision as of 08:09, 3 April 2008

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'''Network Based Application Recognition''' (NBAR)<ref>[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 to recognize a dataflow by the first [[packet (information technology)|packet]] sent.

The [[Computer network|networking]] equipment which uses NBAR does a [[deep packet inspection]] on the first packet in a dataflow, to determine which traffic category the flow belongs to. It then programs the internal [[ASIC]]s to handle this flow appropriately. The categorisationcategorization is usually done with [[OSI-layer4OSI_layer_4]] info, but new applications have made it difficult to cling to this kind of tagging.

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]].

==References==