NHRP Protocol Applicability Statement (RFC2333)
Original Publication Date: 1998-Apr-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
As required by the Routing Protocol Criteria [RFC 1264], this memo discusses the applicability of the Next Hop Resolution Protocol (NHRP) in routing of IP datagrams over Non-Broadcast Multiple Access (NBMA) networks, such as ATM, SMDS and X.25. [STANDARDS-TRACK]
Network Working Group D. Cansever Request for Comments: 2333 GTE Laboratories, Inc. Category: Standards Track April 1998
NHRP Protocol Applicability Statement
Status of this Memo
This document 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" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1998). All Rights Reserved.
As required by the Routing Protocol Criteria [RFC 1264], this memo discusses the applicability of the Next Hop Resolution Protocol (NHRP) in routing of IP datagrams over Non-Broadcast Multiple Access (NBMA) networks, such as ATM, SMDS and X.25.
1. Protocol Documents
The NHRP protocol description is defined in . The NHRP MIB description is defined in .
This document summarizes the key features of NHRP and discusses the environments for which the protocol is well suited. For the purposes of description, NHRP can be considered a generalization of Classical IP and ARP over ATM which is defined in  and of the Transmission of IP Datagrams over the SMDS Service, defined in . This generalization occurs in 2 distinct directions.
Firstly, NHRP avoids the need to go through extra hops of routers when the Source and Destination belong to different Logical Internet Subnets (LIS). Of course,  and  specify that when the source and destination belong to different LISs, the source station must forward data packets to a router that is a member of multiple LISs, even though the source and destination stations may be on the same logical NBMA network. If the source and destination stations belong to the same logical NBMA network, NHRP provides the source station
Cansever Standards Track [Page 1]
RFC 2333 NHRP Protocol Applicability April 1998
with an inter-LIS address resolution mechanism at the end of which both stations can exchange packets without having to use the services of intermediate routers. This feature is also referred to as "short-cut" routing. If the destination station is not part of the logical NBMA network, NHRP provides the source with the NBMA address of the current egress router towards the destination.
The second generalization is that NHRP is not specific to a particular NBMA technology. Of course,  assumes an ATM network and  assumes an SMDS network at their respective subnetwork layers.
NHRP is specified for resolving the destination NBMA addresses of IP datagrams over IP subnets within a large NBMA cloud. NHRP has been designed to be extensible to network layer protocols other than IP, possibly subject to other network layer protocol specific additions.
As an important application of NHRP, the Multiprotocol Over ATM (MPOA) Working Group of the ATM Forum has decided to adopt and to integrate NHRP into its M...