RFC 1517 (rfc1517) - Page 2 of 4
Applicability Statement for the Implementation of Classless Inter-Domain Routing (CIDR)
Alternative Format: Original Text Document
RFC 1517 CIDR Applicability Statement September 1993
explosion problem [1].
2. Components of the Architecture
The CIDR architecture is described in the following documents:
- "An Architecture for IP Address Allocation with CIDR" [2]
- "Classless Inter-Domain Routing (CIDR): An Address Assignment
and Aggregation Strategy" [3]
The first of these documents presents the overall architecture of
CIDR; the second describes the specific address allocation scheme to
be used.
In addition to these two documents, "Guidelines for Management of IP
Address Space" [4] provides specific recommendations for assigning IP
addresses that are consistent with [2] and [3], and "Status of CIDR
Deployment in the Internet" [5] describes the timetable for deploying
[4] in the Internet. Both [4] and [5] should be viewed as
supporting, rather than defining, documents.
In addition to the documents mentioned above, CIDR requires that
inter-domain routing protocols be capable of handling reachability
information that is expressed solely in terms of IP address prefixes.
While several inter-domain routing protocols are capable of
supporting such functionality, this Applicability Statement does not
mandate the use of a particular one.
Although Internet routing domains are not required to use routing
protocols capable of propagating CIDR routes, the topology such
routing domains can support will be somewhat limited. In particular,
the non-CIDR-capable parts of the Internet will need to default
towards the CIDR-capable parts of the Internet for routes which have
been aggregated to non-network boundaries.
3. Applicability of CIDR
The CIDR architecture is applicable to any group of connected domains
that supports IP version 4 [6] [7]. CIDR does not require all of the
domains in the Internet to be converted to use CIDR. It assumes that
some of the existing domains in the Internet will never be able to
convert. Despite this, CIDR will still provide connectivity to such
places, although the optimality of routes to these places may be
impacted.
This Applicability Statement requires Internet domains providing
backbone and/or transit service to fully implement CIDR in order to
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