Common Interval Support in Bidirectional Forwarding Detection (RFC7419)
Original Publication Date: 2014-Dec-01
Included in the Prior Art Database: 2015-Jan-01
Internet Society Requests For Comment (RFCs)
N. Akiya: AUTHOR [+3]
The Bidirectional Forwarding Detection (BFD) standard [RFC5880] describes how to calculate the transmission interval and the detection time. However, it does not make any statement about how to solve a situation where one BFD speaker cannot support the calculated value. In practice, this may not have been a problem as long as software-implemented timers were used and as long as the granularity of such timers was small compared to the interval values being supported, i.e. as long as the error in the timer interval was small compared to 25 percent jitter.
Internet Engineering Task Force (IETF) N. Akiya Request for Comments: 7419 M. Binderberger Updates: 5880 Cisco Systems Category: Informational G. Mirsky ISSN: 2070-1721 Ericsson December 2014
Common Interval Support in Bidirectional Forwarding Detection
Bidirectional Forwarding Detection (BFD) requires that messages be transmitted at regular intervals and provides a way to negotiate the interval used by BFD peers. Some BFD implementations may be restricted to only support several interval values. When such BFD implementations speak to each other, there is a possibility of two sides not being able to find a common value for the interval to run BFD sessions.
This document updates RFC 5880 by defining a small set of interval values for BFD that we call "Common Intervals" and recommends implementations to support the defined intervals. This solves the problem of finding an interval value that both BFD speakers can support while allowing a simplified implementation as seen for hardware-based BFD. It does not restrict an implementation from supporting more intervals in addition to the Common Intervals.
Status of This Memo
This document is not an Internet Standards Track specification; it is published for informational purposes.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7419.
Akiya, et al. Informational [Page 1]
RFC 7419 Common Interval Support in BFD December 2014
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