BFD over Fast OSPF HELLO/HSRP msec Hello

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Sep 7th, 2007
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Can any body let me know the how BFD can be useful to me for faster convergance at control plane during failure compare to OSPF fast hello feature / HSRP hello time in msec....



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aghaznavi Thu, 09/13/2007 - 05:48
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Once the BFD session and appropriate timers have been negotiated, the BFD peers will send BFD control packets to each other at the negotiated interval. As previously mentioned, this assumes BFD Asynchronous mode; BFD Demand mode functions differently. These control packets function as a heartbeat, very similar to an IGP HELLO protocol, except at a more accelerated rate. As long as each BFD peer receives a BFD control packet within the detect-timer period, the BFD session remains up and any routing protocol associated with BFD maintains its adjacencies. If a BFD peer does not receive a control packet within the detect interval, it informs any clients of that BFD session (i.e. any routing protocols) about the failure. It is up to the routing protocol to determine the appropriate response to that information. The typical response will be to terminate the routing protocol peering session and reconverge, bypassing the failed peer


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