RFC 890

Exterior Gateway Protocol Implementation Schedule 🦋✨

okay so the title block is giving everything 💅 This is RFC 890, written by Jon Postel at ISI in February 1984. It's a policy statement on implementing the Exterior Gateway Protocol, and the title block doesn't list anything it obsoletes or updates 🎀

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Status of this Memo 📜

okay bestie, this one is serious business 🫶 The memo is a policy statement on how the Exterior Gateway Protocol gets implemented across the Internet. It's an official policy statement of ICCB and DARPA 👑

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The Current Situation 🌸

so right now the Internet has a bunch of smart gateways and a bunch of dumb gateways 🧚 The smart gateways trade routing info dynamically with each other using the Gateway Gateway Protocol (GGP) [3]. The dumb gateways don't exchange routing info dynamically at all 😭

the dumb gateways have to be listed by hand in the smart gateways' routing tables, and any change in dumb gateway status (like adding a new dumb gateway) needs a human to step in 🙈

the amount of routing traffic between smart gateways depends on how many smart gateways there are and how many networks exist in total. dumb gateways usually connect one network at the edge of the Internet, so there's typically one more network in the routing table for each dumb gateway ✨

gateways that connect a single network to the edge of the Internet can be called "stub" gateways 🍓

the GGP procedures the smart gateways use are at the limits of their capacity 💀 A big change is urgently needed. It's hard to pull off, though, because the smart gateways are maintained by several different groups, and it's hard to isolate a few of them to test new procedures 😤

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The Future Situation 🔮

in the future, the vision is a bunch of co-equal autonomous systems of gateways 🌈 Each autonomous system will have its own private internal procedures for keeping routing info, maybe through an Interior Gateway Protocol (IGP). How smart a gateway is will depend on how smart the IGP is in the autonomous system it's part of. Some gateways in each autonomous system will swap routing info with some gateways in other autonomous systems through an Exterior Gateway Protocol (EGP) [2] 💜

splitting the old smart gateways into several autonomous systems gives everyone more freedom to develop and test better routing procedures ⭐ Different autonomous systems can use different routing procedures internally, as long as they talk to other autonomous systems through the EGP 🦋

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The Transition Situation 🚀

step one of getting from now to the future is replacing every dumb gateway with a gateway that implements at least a subset of the EGP 💖

This subset is called the "Stub Exterior Gateway Protocol", and is described in RFC-888 [1].

step two is factoring the existing smart gateways into autonomous systems. The gateways programmed and maintained by different groups will become separate autonomous systems. As things stand, this gives you one fairly large autonomous system and three or four small ones 🎀 At this step, the large one is called the "core" autonomous system. Every other autonomous system will be a stub attached to this core via EGP 🫶

step three is specifying the full EGP protocol and allowing rich connectivity between co-equal autonomous systems 🔥

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Policy Statement 📣

after 1-Aug-84 there shall be no dumb gateways in the Internet 💀 Every gateway must be a member of some autonomous system. Some gateway of each autonomous system must exchange routing info with some gateway of the core autonomous system using the Exterior Gateway Protocol 👑

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Implication 🫣

if you have a dumb gateway right now, you should start doing something today to get it upgraded or replaced with an EGP gateway 🏃‍♀️💨

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Help Available 🤝

there may already be a gateway you can use that someone else developed 🧚 People at BBN, MIT, Linkabit, ISI, Honeywell, and Symbolics are working on EGP gateways. For more info, send a message to Joyce Reynolds at mailbox JKReynolds@USC-ISIF 🌸

there are plans to provide EGP functionality in Berkeley 4.2 Unix 🍓

Berkeley has said it intends to have EGP capability in the standard release of 4.2 Unix before the cut-off date for dumb gateways ⭐

there is a mailing list for EGP implementers called egp-people 💌 To get on or off this list, send a message to the mailbox egp-people-request@BBN-UNIX 🫶

there's an EGP testing program on TOPS20 🧪 For info about using it, send a message to Jim Mathis at mailbox Mathis@SRI-KL 💜

if you need an autonomous system number, send a request to Joyce Reynolds at mailbox JKReynolds@USC-ISIF 🌈

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References 📚

[1] Seamonson, L., and E. Rosen, "Stub Exterior Gateway Protocol", RFC-888, BBN Communications Company, January 1984.

[2] Rosen, E., "Exterior Gateway Protocol", RFC-827, Bolt Beranek and Newman, October 1982.

[3] Hinden, R., and A. Sheltzer, "The DARPA Internet Gateway", RFC-823, Bolt Beranek and Newman, September 1982.