Hi John,         NBAR2 uses some heuristic techniques to identify encrypted streams of peer-to-peer apps like skype, bittorrent etc. These heuristic "signatures" are constantly updated to keep pace with new versions of supported apps. There's some risk of false-positives or false-negatives for encrypted apps. This is mitigated by rigorous R&D,  and validation of signatures by a dedicated expert team. There's also a process of continuous feedback from live traffic analysis, customer reports etc. In many cases, the apps may also change behavior when completely blocked, and new  behavior may not be caught with the available signatures. To avoid such  situations, we recommend throttling (rather than blocking) of  peer-to-peer traffic. The list of apps supported by NBAR2 is available at: http://www.cisco.com/en/US/prod/collateral/iosswrel/ps6537/ps6558/ps6616/product_bulletin_c25-627831.html Thanks, Shankar ... View more

Hi,    NBAR (Network Based Application Recognition) is a stateful Deep Packet Inspection technology available on Cisco IOS and IOS-XE routers. It can examine the L3-L7 payload of router traffic and identify which application the traffic belongs to as well as some associated properties. Examples of applications are Skype, Youtube, bittorrent, citrix etc. This information is used by other router features such as QoS, Flexible netflow etc. to enable application based services (e.g. marking/policing based on application and reporting application information in netflow records sent to the collector). NBAR2 is the next-generation architectural evolution of NBAR. NBAR2 can identify many applications seen in enterprise and service provide networks. New application support is being added constantly. For more information on NBAR2 features, please see: http://www.cisco.com/en/US/partner/prod/collateral/iosswrel/ps6537/ps6558/ps6616/qa_c67-697963.html There was also a session on NBAR2 at  Cisco Live London 2012: BRKRST-2065 - Application Visibility Control – NBAR2, QoS, FNF and Insight Reporter. The presented material can be accessed by logging into Cisco Live Virtual. ... View more

NBAR2 is is available on ASR1k and ISR-G2 platforms. NBAR2 features are being added incrementally IOS XE release 3.3 and IOS release 15.2(1)T onwards. For more details on specific feature availability in IOS and IOS XE images, please visit: http://www.cisco.com/en/US/docs/ios/15_2m_and_t/release/notes/15_2m_and_t.html http://www.cisco.com/en/US/docs/ios/ios_xe/3/release/notes/asr1k_feats_important_notes_35s.html ... View more