RFC 1721

RFC 1721: RIP Version 2 Protocol Analysis 🦋

okay bestie, this one is the RIP-2 analysis report, and it's giving "here's the receipts that RIP-2 is ready for the standards track" 💅✨

• Number and title: RFC 1721, RIP Version 2 Protocol Analysis 🎀
• Series: Network Working Group
• Author: G. Malkin, also known as Gary Scott Malkin, at Xylogics, Inc. 🫶
• Category: Informational
• Date: November 1994 🌸
• Obsoletes: 1387

---

Status of this Memo

this memo is giving information for the Internet community 🧚 it does not specify an Internet standard of any kind, and distribution of it is unlimited 💜

Abstract

so the abstract is basically: as Routing Protocol Criteria (RFC 1264) requires, this report documents the key features of the RIP-2 protocol and the current implementation experience ✨ it's also a prerequisite to advancing RIP-2 on the standards track, so this is the homework before the big glow-up 🦋

Acknowledgements

RIP-2 owes so much to everyone who showed up for the RIP-2 working group 🫶 a special shoutout goes to Fred Baker for his help on the MIB, and to Jeffrey Honig for all his comments 💖

---

1. Protocol Documents 📚

the RIP-2 applicability statement is defined in RFC 1722 [1] 🌈

the RIP-2 protocol description is defined in RFC 1723 [2] ✨ this memo obsoletes RFC 1388, which specifies an update to the "Routing Information Protocol" RFC 1058 (STD 34) 💅

the RIP-2 MIB description is defined in RFC 1724 [3] 🎀 this memo obsoletes RFC 1389 🙈

2. Key Features 👑

okay so RIP-2 shares the same basic algorithms as RIP-1, but it adds some new stuff: external route tags, subnet masks, next hop addresses, and authentication 🔥 the biggest change from RFC 1388 is removing the domain field 💀 nobody had a clear agreement on how it would be used, so it got left reserved for future expansion 🍓

2.1 External Route Tags 🏷️

the route tag field may be used to propagate information acquired from an EGP 🌸 what goes in that field is beyond the scope of this protocol, but it may be used, for example, to propagate an EGP AS number 💜

2.2 Subnet Masks 🎀

including subnet masks was the original reason anyone opened RIP up for improvement, and honestly it's iconic 👑 subnet mask info makes RIP way more useful in lots of environments and lets you use variable subnet masks on the network ✨ subnet masks are also necessary for "classless" addressing, the way the CIDR work proposes 🦋

2.3 Next Hop Addresses 🧚

next hop addresses let you optimize routes in an environment running multiple routing protocols 🌈 picture RIP-2 running on a network with another IGP, and one router running both: that router can tell the other RIP-2 routers that a better next hop than itself exists for a given destination 😭

2.4 Authentication 🔐

this is a major glow-up over RIP-1: RIP-2 adds an authentication mechanism ✨ it's basically the same extensible mechanism OSPF uses 💅 right now only a plain-text password is defined, but more sophisticated authentication schemes can easily be incorporated as they get defined 🔥

2.5 Multicasting 📡

RIP-2 packets may be multicast instead of broadcast 🌸 using an IP multicast address takes load off hosts that don't support routing protocols 🫶 it also lets RIP-2 routers share info that RIP-1 routers can't hear 💖 and this matters because a RIP-1 router may misinterpret route info when it can't apply the supplied subnet mask 🙈

3. RIP-2 MIB 🗂️

the MIB for RIP-2 lets you monitor and control RIP's operation inside the router 💜 on top of global and per-interface counters and controls, there are per-peer counters that show the status of RIP-2 "neighbors" 👑

the MIB got modified to deprecate the domain, which was removed from the protocol 💀 it's also been converted into version 2 format ✨

4. Implementations 🛠️

there are three complete implementations of RIP-2 right now 🎉 first up is GATED, written by Jeffrey Honig at Cornell University. Then there's Xylogics's Annex Communication server, and an implementation for NOS, written by Jeff White 🌈

you can grab GATED by anonymous FTP from gated.cornell.edu as pub/gated/gated-alpha.tar.Z 🧚 the NOS implementation is available by anonymous FTP from ucsd.edu as /hamradio/packet/tcpip/incoming/rip2.zip 💅

also, Midnight Networks made a test suite that checks whether an implementation conforms to RFC 1388 implemented over RFC 1058 🔥

the author did interoperability testing between the GATED and Xylogics implementations and found no incompatibilities 🫶 that testing included verifying the protection the authentication mechanism from section 2.4 provides 🔐

5. Operational experience 🌟

Xylogics has been running RIP-2 on its production systems for five months, and it's been a whole vibe 💅 the topology has seven subnets in a class B address, plus various unregistered class C addresses used for dial-up access 🌸 six systems, along with three routers from other vendors and dozens of host systems, operate on those subnets 👑

the only problem that popped up was how some routers reacted to Version 2 RIP packets 😭 contrary to RFC 1058, these routers discard Version 2 packets instead of ignoring the fields not defined for Version 1 💀

6. References 📖

[1] Malkin, G., "RIP Version 2 Protocol Applicability Statement", RFC 1722, Xylogics, Inc., November 1994.

[2] Malkin, G., "RIP Version 2 - Carrying Additional Information", RFC 1723, Xylogics, Inc., November 1994.

[3] Malkin, G., and F. Baker, "RIP Version 2 MIB Extension", RFC 1724, Xylogics, Inc., Cisco Systems, November 1994.

7. Security Considerations 🚨

okay this part is serious bestie 😭 security issues are discussed in sections 2.4 and 4, so go check those out before you do anything else 🔐💀

8. Author's Address 📮

Gary Scott Malkin
Xylogics, Inc.
53 Third Avenue
Burlington, MA 01803

Phone:  (617) 272-8140
EMail:  gmalkin@Xylogics.COM