Revisions to the BGP 'Minimum Route Advertisement Interval'
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paul@jakma.org
Routing
Inter-Domain Routing
BGP
IDR
MRAI
Convergence
This document revises the specification of the BGP MRAI timer, by
deprecating the previously recommended values and by allowing for
withdrawals to be exempted from the MRAI.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in .
The Minimum Route Advertisement Interval (MRAI) timer is specified in
RFC4271. This timer acts to rate-limit
updates, on a per-destination basis. suggests
values of 30s and 5s for this interval for eBGP and iBGP respectively.
The MRAI must also be applied to withdrawals according to RFC4271, a
change from the earlier RFC1771.
The MRAI timer has a significant effect on the convergence of BGP,
in terms of convergence time, the number of messages, amongst other
metrics. The optimum value for this timer is hard to estimate, never
mind calculate and will differ between networks, and probably even
different subsets of the same network.
The suggested default values for the MinRouteAdvertisementIntervalTimer
given in RFC4271 are deprecated. The
appropriate choice of default values is left to the discretion of
implementors. Implementations SHOULD provide a means to allow operators
to choose values appropriate to their requirements, on a per-peer and
per-AFI/SAFI basis. Implementations MAY exempt withdrawals from the
MRAI timer.
There are no requests made to IANA in this document.
This document raises no new security considerations.
A Border Gateway Protocol 4 (BGP-4)
Unknown
Unknown
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Key words for use in RFCs to Indicate Requirement
Levels
Harvard University