Dynamic Hostname Exchange Mechanism for IS-IS
RFC 5301

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Network Working Group                                       D. McPherson
Request for Comments: 5301                                Arbor Networks
Obsoletes: 2763                                                  N. Shen
Category: Standards Track                                  Cisco Systems
                                                            October 2008

             Dynamic Hostname Exchange Mechanism for IS-IS

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.

Abstract

   RFC 2763 defined a simple and dynamic mechanism for routers running
   IS-IS to learn about symbolic hostnames.  RFC 2763 defined a new TLV
   that allows the IS-IS routers to flood their name-to-systemID mapping
   information across the IS-IS network.

   This document obsoletes RFC 2763.  This document moves the capability
   provided by RFC 2763 to the Standards Track.

Table of Contents

   1. Introduction ....................................................2
      1.1. Specification of Requirements ..............................2
   2. Possible Solutions ..............................................2
   3. Dynamic Hostname TLV ............................................3
   4. Implementation ..................................................4
   5. Security Considerations .........................................4
   6. Acknowledgments .................................................4
   7. IANA Considerations .............................................4
   8. Informative References ..........................................4

McPherson & Shen            Standards Track                     [Page 1]
RFC 5301                    Dynamic Hostname                October 2008

1.  Introduction

   IS-IS uses a variable 1-8 byte system ID (normally 6 bytes) to
   represent a node in the network.  For management and operation
   reasons, network operators need to check the status of IS-IS
   adjacencies, entries in the routing table, and the content of the
   IS-IS link state database.  It is obvious that, when looking at
   diagnostics information, hexadecimal representations of system IDs
   and Link State Protocol Data Unit (LSP) identifiers are less clear
   than symbolic names.

   One way to overcome this problem is to define a name-to-systemID
   mapping on a router.  This mapping can be used bidirectionally, e.g.,
   to find symbolic names for system IDs and to find system IDs for
   symbolic names.  One way to build this table of mappings is by static
   definitions.  Among network administrators who use IS-IS as their
   IGP, it is current practice to define such static mappings.

   Thus, every router has to maintain a statically-configured table with
   mappings between router names and system IDs.  These tables need to
   contain the names and system IDs of all routers in the network, and
   must be modified each time an addition, deletion, or change occurs.

   There are several ways one could build such a table.  One is via
   static configurations.  Another scheme that could be implemented is
   via DNS lookups.  In this document, we provide a third solution,
   which in wide-scale implementation and deployment has proven to be
   easier and more manageable than static mapping or DNS schemes.

1.1.  Specification of Requirements

   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 [RFC2119].

2.  Possible Solutions

   The obvious drawback of static configuration of mappings is the issue
   of scalability and maintainability.  The network operators have to
   maintain the name tables.  They have to maintain an entry in the
   table for every router in the network, on every router in the
   network.  The effort to create and maintain these static tables grows
   with the total number of routers on the network.  Changing the name
   or system ID of one router, or adding a new router will affect the
   configurations of all the other routers on the network.  This will
   make it very likely that those static tables are outdated.

McPherson & Shen            Standards Track                     [Page 2]
RFC 5301                    Dynamic Hostname                October 2008

   Having one table that can be updated in a centralized place would be
   helpful.  One could imagine using the DNS system for this.  A
   drawback is that during the time of network problems, the response
   time of DNS services might not be satisfactory or the DNS services
   might not even be available.  Another possible drawback might be the
   added complexity of DNS.  Also, some DNS implementations might not