From 4bfd864f10b68b71482b35c818559068ef8d5797 Mon Sep 17 00:00:00 2001 From: Thomas Voss Date: Wed, 27 Nov 2024 20:54:24 +0100 Subject: doc: Add RFC documents --- doc/rfc/rfc1517.txt | 227 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 227 insertions(+) create mode 100644 doc/rfc/rfc1517.txt (limited to 'doc/rfc/rfc1517.txt') diff --git a/doc/rfc/rfc1517.txt b/doc/rfc/rfc1517.txt new file mode 100644 index 0000000..3022c92 --- /dev/null +++ b/doc/rfc/rfc1517.txt @@ -0,0 +1,227 @@ + + + + + + +Network Working Group Internet Engineering Steering Group +Request for Comments: 1517 R. Hinden, Editor +Category: Standards Track September 1993 + + + Applicability Statement for the Implementation of + Classless Inter-Domain Routing (CIDR) + +Status of this Memo + + This RFC specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" for the standardization state and status + of this protocol. Distribution of this memo is unlimited. + +1. Introduction + + As the Internet has evolved and grown in recent years, it has become + clear that it will soon face several serious scaling problems. These + include: + + - Exhaustion of the class-B network address space. One + fundamental cause of this problem is the lack of a network + class of a size that is appropriate for a mid-sized + organization. Class-C, with a maximum of 254 host addresses, is + too small, while class-B, which allows up to 65534 addresses, + is too large to be densely populated. The result is inefficient + utilization of class-B network numbers. + + - Routing information overload. The size and rate of growth of the + routing tables in Internet routers is beyond the ability of + current software (and people) to effectively manage. + + - Eventual exhaustion of IP network numbers. + + It has become clear that the first two of these problems are likely + to become critical in the near term. Classless Inter-Domain Routing + (CIDR) ttempts to deal with these problems by defining a mechanism to + slow the growth of routing tables and reduce the need to allocate new + IP network numbers. It does not attempt to solve the third problem, + which is of a more long-term nature, but instead endeavors to ease + enough of the short to mid-term difficulties to allow the Internet to + continue to function efficiently while progress is made on a longer- + term solution. + + The IESG, after a thorough discussion in the IETF, in June 1992 + selected CIDR as the solution for the short term routing table + + + +IESG [Page 1] + +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 + + + +IESG [Page 2] + +RFC 1517 CIDR Applicability Statement September 1993 + + + ensure that the growth of the resources required by routers to + provide Internet-wide connectivity will be significantly slower than + the growth of the number of assigned networks. + + This Applicability Statement strongly recommends that all non- + backbone/transit Internet domains also implement CIDR because it will + reduce the amount of routing information inside of these domains. + + Individual domains are free to choose whatever inter-domain and + intra-domain routing architectures best meet their requirements. + Specifically, this Applicability Statement does not prevent a domain + or a group of domains from using addressing schemes which do not + conform to CIDR. Subject to the available resources in routers, CIDR + should be able to co-exist with other addressing schemes without + adversely impacting overall connectivity. + +4. References + + [1] Gross, P., and P. Almquist, "IESG Deliberations on Routing and + Addressing", RFC 1380, IESG Chair, IESG Internet AD, November + 1992. + + [2] Rekhter, Y., and T. Li, "An Architecture for IP Address + Allocation with CIDR", RFC 1518, T.J. Watson Research Center, IBM + Corp., cisco Systems, September 1993. + + [3] Fuller, V., Li, T., Yu, J., and K. Varadhan, "Classless Inter- + Domain Routing (CIDR): An Address Assignment and Aggregation + Strategy", RFC 1519, BARRNet, cisco, Merit, and OARnet, September + 1993. + + [4] Gerich, E., "Guidelines for Management of IP Address Space", RFC + 1466, Merit, May 1993. + + [5] Topolcic, C., "Status of CIDR Deployment in the Internet", RFC + 1467, CNRI, August 1993. + + [6] Postel, J., "Internet Protocol - DARPA Internet Program Protocol + Specification", STD 5, RFC 791, USC/Information Sciences + Institute, September 1981. + + [7] Braden, R., Editor, "Requirements for Internet Hosts -- + Communication Layers", STD 3, RFC 1122, IETF, October 1989. + +5. Security Considerations + + Security issues are not discussed in this memo. + + + + +IESG [Page 3] + +RFC 1517 CIDR Applicability Statement September 1993 + + +6. Author's Address + + Robert M. Hinden + Sun Microsystems + 2550 Garcia Ave, MS MTV5-44 + Mt. View, CA 94043 + + Phone: (415) 336-2082 + Fax: (415) 336-6015 + + EMail: hinden@eng.sun.com + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +IESG [Page 4] + \ No newline at end of file -- cgit v1.2.3