EGP schedule: Exterior Gateway Protocol implementation schedule
Official policy requiring all Internet gateways to implement the Exterior Gateway Protocol by August 1, 1984
Postel, J., "Exterior Gateway Protocol implementation schedule", RFC 890, DOI 10.17487/RFC0890, February 1984, <https://www.rfc-editor.org/info/rfc890>.
@misc{rfc890,
series = {Request for Comments},
number = 890,
howpublished = {RFC 890},
publisher = {RFC Editor},
doi = {10.17487/RFC0890},
url = {https://www.rfc-editor.org/info/rfc890},
author = {J. Postel},
title = {{Exterior Gateway Protocol implementation schedule}},
pagetotal = 3,
year = 1984,
month = feb,
} RFC text
Contents
Network Working Group Jon Postel
Request for Comments: 890 ISI
February 1984
Exterior Gateway Protocol Implementation Schedule
Status of this Memo
This memo is a policy statement on the implementation of the Exterior
Gateway Protocol in the Internet. This is an official policy
statement of ICCB and DARPA.
The Current Situation
Currently the Internet has a number of smart gateways and a number of
dumb gateways. The smart gateways dynamically exchange routing
information among themselves using the Gateway Gateway
Protocol (GGP) [3]. The dumb gateways do not exchange routing
information dynamically.
The dumb gateways must be listed in the smart gateway routing tables,
and changes in dumb gateways status (e.g., adding new dumb gateways)
in the smart gateways tables requires human intervention.
The amount of routing traffic between smart gateways depends on the
number of smart gateways and the total number of networks. Since
dumb gateways typically connect a single network at the edge of the
Internet, there is typically one more network in the routing table
for each dumb gateway.
Gateways that connect a single network to the edge of the Internet
may be called "stub" gateways.
The current GGP procedures used by the smart gateways are at the
limits of their capacity. A significant change to these procedures
is urgently required. This is difficult to perform because the smart
gateways are maintained by several different groups, and because it
is difficult to isolate a subset of these gateways for testing new
procedures.
The Future Situation
In the future, as it is currently envisioned, there will be a number
of co-equal autonomous systems of gateways. Each as will have its
own private internal procedures for maintaining routing information,
perhaps via an Interior Gateway Protocol (IGP). The smartness of a
gateway will be the smartness of the IGP used in the autonomous
system the gateway participates in. Some gateways of each autonomous
system will exchange routing informations with some gateways of other
autonomous systems via an Exterior Gateway Protocol (EGP) [2].
EGP Implementation Schedule
The factoring of the old set of smart gateways into a number of
autonomous systems allows more flexibility for the development and
testing of improved routing procedures. Different autonomous systems
can adopt different routing procedures internally, as long as they
communicate with other autonomous systems via the EGP.
The Transition Situation
The first step in the transition from the current situation to the
future situation is the replacement of all dumb gateways with
gateways that implement at least a subset of the EGP.
This subset is called the "Stub Exterior Gateway Protocol", and is
described in RFC-888 [1].
The second step is to factor the existing smart gateways into
autonomous systems. The gateways programmed and maintained by
different groups will become distinct autonomous systems. As things
are, this will result in one fairly large autonomous system and three
or four small autonomous systems. At this step the large autonomous
system will be referred to as the "core" autonomous system. All
other autonomous systems will be stubs attached to this core via EGP.
The third step is to specify the full EGP protocol, and to allow a
rich connectivity between co-equal autonomous systems.
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 information
with some gateway of the core autonomous system using the Exterior
Gateway Protocol.
Implication
If you have a dumb gateway now, you should start doing something
today to get it upgraded to, or replaced by, an EGP gateway.
Help Available
There may be a gateway you can use already developed by someone.
People at the following places are working on EGP gateways: BBN,
MIT, Linkabit, ISI, Honeywell, and Symbolics. For more information
send a message to Joyce Reynolds at mailbox "JKReynolds@USC-ISIF".
There are plans to provide EGP functionality in Berkeley 4.2 Unix.
EGP Implementation Schedule
Berkeley has indicated an intention to have EGP capability available
in the standard release of 4.2 Unix before the cut off date for dumb
gateways.
The 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 is a EGP testing program available on TOPS20. For information
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".
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.
AI ELI5
On this page
§1The Current Routing Problem
The Internet has two kinds of gateways: smart gateways that dynamically exchange routing information using GGP, and dumb gateways that are manually configured. Dumb gateways must be hand-entered into routing tables, and any change requires human intervention.
The current GGP system is at capacity limits. Gateways maintained by different groups cannot easily adopt improved routing procedures because any change must be coordinated across all smart gateways simultaneously. This architecture prevents the flexibility needed for network growth.
Some routers talked to each other automatically, but new ones were configured by hand. The automatic system was so full it could not grow anymore.
§2The Future Model: Autonomous Systems
The solution divides the Internet into autonomous systems (ASes), each with its own internal routing procedures via an Interior Gateway Protocol (IGP). Different autonomous systems can use different IGPs. The systems communicate externally using the Exterior Gateway Protocol (EGP).
This three-step transition plan: first, upgrade all dumb gateways to implement stub EGP; second, partition existing smart gateways into autonomous systems with a core system and several stub systems attached via EGP; third, complete the EGP protocol and allow rich connectivity between co-equal autonomous systems.
Split the network into teams. Each team manages its own internal routing. Teams talk to each other using one standard language (EGP). Different teams can use different internal methods.
§3The Mandate
The RFC contains an official ICCB and DARPA policy statement: after 1 August 1984, there shall be no dumb gateways in the Internet. Every gateway must be a member of an autonomous system, and some gateway of each system must exchange routing information with the core autonomous system using EGP.
Implementation help is available from BBN, MIT, Linkabit, ISI, Honeywell, and Symbolics. A mailing list called egp-people coordinates implementers, and Berkeley's 4.2 Unix is planned to include EGP capability. An EGP testing program is available on TOPS-20.
This is the official rule. By August 1984, all routers must be updated. Help is available. After that date, every router follows the new system.