rfc2834.txt

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Network Working Group                                        J.-M. Pittet
Request for Comments: 2834                          Silicon Graphics Inc.
Obsoletes: 1374                                                  May 2000
Category: Standards Track


                  ARP and IP Broadcast over HIPPI-800

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 Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   This document specifies a method for resolving IP addresses to ANSI
   High-Performance Parallel Interface (HIPPI) hardware addresses and
   for emulating IP broadcast in a logical IP subnet (LIS) as a direct
   extension of HARP. This memo defines a HARP that will interoperate
   between HIPPI-800 and HIPPI-6400 (also known as Gigabyte System
   Network, GSN). This document (when combined with RFC-2067 "IP over
   HIPPI") obsoletes RFC-1374.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
       3.1 Global Concepts . . . . . . . . . . . . . . . . . . .   3
       3.2 Glossary  . . . . . . . . . . . . . . . . . . . . . .   3
   4.  IP Subnetwork Configuration . . . . . . . . . . . . . . .   5
       4.1 Background  . . . . . . . . . . . . . . . . . . . . .   5
       4.2 HIPPI LIS Requirements  . . . . . . . . . . . . . . .   6
   5.  HIPPI Address Resolution Protocol - HARP  . . . . . . . .   7
       5.1 HARP Algorithm  . . . . . . . . . . . . . . . . . . .   8
           5.1.1 Selecting the authoritative HARP service  . . .   8
           5.1.2 HARP registration phase . . . . . . . . . . . .   9
           5.1.3 HARP operational phase  . . . . . . . . . . . .  10
   5.2 HARP Client Operational Requirements  . . . . . . . . . .  11
       5.3 Receiving Unknown HARP Messages . . . . . . . . . . .  12
       5.4 HARP Server Operational Requirements  . . . . . . . .  12



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       5.5 HARP and Permanent ARP Table Entries  . . . . . . . .  14
       5.6 HARP Table Aging  . . . . . . . . . . . . . . . . . .  14
   6.  HARP Message Encoding . . . . . . . . . . . . . . . . . .  15
       6.1 HIPPI-LE Header of HARP Messages  . . . . . . . . . .  15
           6.1.1 IEEE 802.2 LLC  . . . . . . . . . . . . . . . .  16
           6.1.2 SNAP  . . . . . . . . . . . . . . . . . . . . .  16
           6.1.3 Diagram . . . . . . . . . . . . . . . . . . . .  17
       6.2 HIPPI Hardware Address Formats and Requirements . . .  18
           6.2.1 48-bit Universal LAN MAC Addresses  . . . . . .  18
       6.3 HARP and InHARP Message Formats . . . . . . . . . . .  19
           6.3.1 Example Message encodings . . . . . . . . . . .  22
           6.3.2 HARP_NAK message format . . . . . . . . . . . .  22
           6.3.3 Combined HIPPI-LE and HARP message addresses  .  22
   7.  Broadcast and Multicast . . . . . . . . . . . . . . . . .  23
       7.1 Protocol for an IP Broadcast Emulation Server - PIBES  23
       7.2 IP Broadcast Address  . . . . . . . . . . . . . . . .  24
       7.3 IP Multicast Address  . . . . . . . . . . . . . . . .  24
       7.4 A Note on Broadcast Emulation Performance . . . . . .  24
   8.  HARP for Scheduled Transfer Protocol  . . . . . . . . . .  25
   9.  Discovery of One's Own Switch Address . . . . . . . . . .  25
   10. Security Considerations . . . . . . . . . . . . . . . . .  26
   11. Open Issues . . . . . . . . . . . . . . . . . . . . . . .  26
   12. HARP Examples . . . . . . . . . . . . . . . . . . . . . .  26
       12.1 Registration Phase of Client Y on Non-broadcast HW .  27
       12.2 Registration Phase of Client Y on Broadcast Hardware  28
       12.3 Operational Phase (phase II) . . . . . . . . . . . .  28
            12.3.1 Standard successful HARP_Resolve example  . .  29
            12.3.2 Standard non-successful HARP_Resolve example   30
   13. References  . . . . . . . . . . . . . . . . . . . . . . .  31
   14. Acknowledgments . . . . . . . . . . . . . . . . . . . . .  32
   15. Changes from RFC-1374 . . . . . . . . . . . . . . . . . .  32
   16. Author's Address  . . . . . . . . . . . . . . . . . . . .  33
   17. Full Copyright Statement  . . . . . . . . . . . . . . . .  34

1. Introduction

   The ANSI High-Performance Parallel Interface (HIPPI) is a dual
   simplex data channel.   HIPPI can send and receive data
   simultaneously at 800 or 1600 megabits per second. Between 1987 and
   1997, the ANSI X3T11.1 HIPPI working group (now known as NCITS T11.1)
   Standardized five documents that bear on the use of HIPPI as a
   network interface.  They cover the physical and electrical
   specification (HIPPI-PH [1]), the framing of a stream of bytes
   (HIPPI-FP [2]), encapsulation of IEEE 802.2 LLC (HIPPI-LE [3]), the
   behavior of a physical layer switch (HIPPI-SC [4]) and the physical-
   level and optical specification (HIPPI-Serial [5]).  HIPPI-LE also
   implies the encapsulation of Internet Protocol[5].  The reader should
   be familiar with the ANSI HIPPI documents. Approved ANSI NCITS



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   standards are available from ANSI (http://www.ansi.org). The working
   documents of the T11.1 working group may be obtained from the T11 web
   page (http://www.t11.org/).

   HIPPI switches can be used to connect a variety of computers and
   peripheral equipment for many purposes, but the working group stopped
   short of describing their use as Local Area Networks.  RFC-2067 [15]
   describes the encapsulation of IP over HIPPI-800. This memo takes up
   where the working group and RFC-2067 [15] left off and defines
   address resolution and LIS IP broadcast emulation for HIPPI-800
   networks.

   While investigating possible solutions for HARP it became evident
   that IP broadcast could easily be emulated for both HIPPI-800 and
   HIPPI-6400 hardware types. This is useful since HIPPI switches are
   not required to implement broadcast but many standard networking
   protocols rely on broadcast.  This memo therefore further addresses
   the emulation of LIS IP broadcast as an extension of HARP.

2 Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC-2119 [18].

3. Definitions

3.1 Global concepts used

   In the following discussion, the terms "requester" and "target" are
   used to identify the port initiating the address resolution request
   and the port whose address it wishes to discover, respectively.  If
   not all switches in the LIS support broadcast then there will be a
   HARP server providing the address resolution service and it will be
   the source of the reply. If on the other hand all switches support
   broadcast then the source address of a reply will be the target's
   target address.

   Values are decimal unless otherwise noted. Formatting follows IEEE
   802.1A canonical bit order and and HIPPI-FP bit and byte order.

3.2 Glossary

   Broadcast

   A distribution mode which transmits a message to all ports.
   Particularly also the port sending the message.




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   Classical/Conventional

   Both terms are used to refer to networks such as Ethernet, FDDI, and
   other 802 LAN types, as distinct from HIPPI-SC LANs.

   Destination

   The HIPPI port that receives data from a HIPPI Source.

   HARP

   HARP describes the whole set of HIPPI address resolution encodings
   and algorithms defined in this memo. HARP is a combination and
   adaptation of the Internet Address Resolution Protocol (ARP) RFC-826
   [13] and Inverse ARP (InARP) [7] (see section 5). HARP also describes
   the HIPPI specific version of ARP [10] (i.e. the protocol and the
   HIPPI specific encoding).

   HARP table

   Each host has a HARP table which contains the IP to hardware address
   mapping of IP members.

   HIPPI-Serial

   An implementation of HIPPI in serial fashion on coaxial cable or
   optical fiber. (see [5])

   HRAL

   The HARP Request Address List.  A list of ULAs to which HARP messages
   are sent when resolving names to addresses (see section 4.2).

   Hardware (HW) address

   The hardware address of a port consisting of an I-Field and an
   optional ULA (see section 6.2). Note: the term port as used in this
   document refers to a HIPPI port and is roughly equivalent to the term
   "interface" as commonly used in other IP documents.

   Host

   An entity, usually a computer system, that may have one or more HIPPI
   ports and which may serve as a client or a HARP server.







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   Port

   An entity consisting of one HIPPI Source/Destination dual simplex
   pair that is connected by parallel or serial HIPPI to a HIPPI-SC
   switch and that transmits and receives IP datagrams.

   PIBES

   The Protocol for Internet Broadcast Emulation Server (see section 7).

   Switch Address

   A value used as the address of a port on a HIPPI-SC network.  It is
   transmitted in the I-field.  HIPPI-SC switches map Switch Addresses
   to physical switch port numbers. The switch address is extended with
   a mode byte to form an I-Field (see [4] and 6.2.2)

   Source

   The HIPPI port that generates data to send to a HIPPI Destination.

   Universal LAN MAC Address (ULA)

   A 48-bit globally unique address, administered by the IEEE, assigned
   to each port on an Ethernet, FDDI, 802 network, or HIPPI-SC LAN.

4.  IP Subnetwork Configuration

4.1 Background

   ARP (address resolution protocol) as defined in [12] was meant to
   work on the 'local' cable. This definition gives the ARP protocol a
   local logical IP subnet (LIS) scope. In the LIS scenario, each
   separate administrative entity configures its hosts and routers
   within the LIS. Each LIS operates and communicates independently of
   other LIS's on the same HIPPI network.

   HARP has LIS scope only and serves all ports in the LIS.
   Communication to ports located outside of the local LIS is usually
   provided via an IP router. This router is a HIPPI port attached to
   the HIPPI network that is configured as a member of one or more
   LIS's. This configuration MAY result in a number of disjoint LIS's
   operating over the same HIPPI network. Using this model, ports of
   different IP subnets SHOULD communicate via an intermediate IP router
   even though it may be possible to open a direct HIPPI connection
   between the two IP members over the HIPPI network. This is a
   consequence of using IP and choosing to have multiple LIS's on the
   same HIPPI fabric.



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   By default, the HARP method detailed in section 5 and the classical
   LIS routing model MUST be available to any IP member client in the
   LIS.

4.2 HIPPI LIS Requirements

   The requirement for IP members (hosts, routers) operating in a HIPPI
   LIS configuration is:

   o  All members of the LIS SHALL have the same IP network/subnet
      address and address mask [6].

   The following list identifies the set of HIPPI-specific parameters
   that MUST be implemented in each IP station connected to the HIPPI
   network:

   o  HIPPI Hardware Address:

      The HIPPI hardware address of an individual IP port MUST contain
      the port's Switch Address (see section 9). The address SHOULD also
      contain a non-zero ULA address. If there is no ULA then that field
      MUST be zero.