RFC 1656 (rfc1656) - Page 2 of 4
BGP-4 Protocol Document Roadmap and Implementation Experience
Alternative Format: Original Text Document
RFC 1656 BGP-4 Implementation July 1994
ANS (gated)
Europanet
3COM
cisco
The complete interoperability matrix between all known
implementations of various versions of BGP is available under
separate cover [9].
Implementation Testing
One implementation has been extensively tested in a network designed
to mirror the complex connectivity present at many major Internet
borders. This network consists of multiple BGP-3 and BGP-4 speakers
carrying full routing information injected from Alternet, EBone,
Sprint, CERFnet, and cisco. In many cases additional AS adjacencies
are simulated via the use of IP over IP tunnels to increase the
complexity of the routing topology.
The primary feature of BGP-4 is the ability to carry network
reachability information without regard to classfull routing. In
addition to canonical routing information, CIDR prefixes (both
supernets and subnets) are being injected from IGP information and
aggregated using the methods described in BGP-4. AS set aggregation
and policy decisions based upon AS sets have been tested.
Secondary extensions incorporated as part of version 4 of this
protocol include enhancements to use of the INTER_AS_METRIC (now
called MULTI_EXIT_DISC), the addition of a LOCAL_PREF parameter to
influence route selection within an AS, and a specified method of
damping route fluctuations. All of these features have been tested
in at least one implementation.
Observations
All implementations, are able to carry and exchange network
reachability information.
Not all implementations are capable of generating aggregate
information based upon the existence of more specific routes.
No implementation supports automatic deaggregation (enumeration of
all networks in an aggregate block for backwards compatibility with
routing protocols that do not carry mask information (e.g. BGP-3)).
However, most implementations do allow for staticly configured
controlled deaggregation for minimal backwards compatibility with
non-CIDR capable routers.
Traina