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Directed ARP (RFC1433)

IP.com Disclosure Number: IPCOM000002261D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 14 page(s) / 38K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Garrett: AUTHOR [+3]

Abstract

A router with an interface to two IP networks via the same link level interface could observe that the two IP networks share the same link level network, and could advertise that information to hosts (via ICMP Redirects) and routers (via dynamic routing protocols). However, a host or router on only one of the IP networks could not use that information to communicate directly with hosts and routers on the other IP network unless it could resolve IP addresses on the "foreign" IP network to their corresponding link level addresses. Directed ARP is a dynamic address resolution procedure that enables hosts and routers to resolve advertised potential next-hop IP addresses on foreign IP networks to their associated link level addresses.

This text was extracted from a ASCII document.
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Network Working Group J. Garrett

Request for Comments: 1433 AT&T Bell Laboratories

J. Hagan

University of Pennsylvania

J. Wong

AT&T Bell Laboratories

March 1993

Directed ARP

Status of this Memo

This memo defines an Experimental Protocol for the Internet

community. Discussion and suggestions for improvement are requested.

Please refer to the current edition of the "IAB Official Protocol

Standards" for the standardization state and status of this protocol.

Distribution of this memo is unlimited.

Abstract

A router with an interface to two IP networks via the same link level

interface could observe that the two IP networks share the same link

level network, and could advertise that information to hosts (via

ICMP Redirects) and routers (via dynamic routing protocols).

However, a host or router on only one of the IP networks could not

use that information to communicate directly with hosts and routers

on the other IP network unless it could resolve IP addresses on the

"foreign" IP network to their corresponding link level addresses.

Directed ARP is a dynamic address resolution procedure that enables

hosts and routers to resolve advertised potential next-hop IP

addresses on foreign IP networks to their associated link level

addresses.

Acknowledgments

The authors are indebted to Joel Halpern of Network Systems

Corporation and David O'Leary who provided valuable comments and

insight to the authors, as well as ongoing moral support as the

presentation of this material evolved through many drafts. Members

of the IPLPDN working group also provided valuable comments during

presentations and through the IPLPDN mailing list. Chuck Hedrick of

Rutgers University, Paul Tsuchiya of Bell Communications Research,

and Doris Tillman of AT&T Bell Laboratories provided early insight as

well as comments on early drafts.

1. Terminology

A "link level network" is the upper layer of what is sometimes

referred to (e.g., OSI parlance) as the "subnetwork", i.e., the

layers below IP. The term "link level" is used to avoid potential

confusion with the term "IP sub-network", and to identify addresses

(i.e., "link level address") associated with the network used to

transport IP datagrams.

From the perspective of a ho...