CURRENT_MEETING_REPORT_

Reported by Isidro Castineyra/Bolt Beranek and Newman

Minutes of the New Internet Routing and Addressing Architecture
Working Group (NIMROD)


Preface

The NIMROD Working Group met on Tuesday, 4 April, and on Wednesday, 5
April.  The agenda for the meeting was:


   o Tuesday
      -  Agenda bashing/Announcements
      -  Overview of the Deployment Document (Charlie Lynn)
      -  Configuration vs.  Discovery (Martha Steenstrup)
      -  Discussion

   o Wednesday
      -  What is in the Nimrod Model (Martha Steenstrup and Isidro
         Castineyra)
      -  Software Architecture (Charlie Lynn)
      -  Discussion
      -  Open Issues and Work Plan


Deployment Document

Charlie Lynn gave an overview of the Deployment Document.  He discussed
strategies for the gradual integration of Nimrod in the Internet.


Configuration vs.  Discovery

Martha Steenstrup presented a list of information elements that could be
obtained by either configuration or discovery.  For each element, Martha
discussed the trade-offs and the current thoughts on what to do with
that element.  Highlights of her presentation follow.


   o The goal is to make both a ``plug-and-play'' system and to make
     everything configurable.

   o Configured items:

      -  At Node Representatives:  adjacency formation constraints,
         association constraints, set of locator elements for component
         nodes.

      -  At Endpoint Representatives:  EIDs and names of endpoints,
         association constraints, multicast group membership of
         endpoints.

      -  At Forwarding Agents:  traffic restrictions.

      -  At Agents:  type of agent, EID of agent, nodes on which behalf
         the agent acts (configured).


Martha will be posting the slides she used to the working group mailing
list.


Nimrod Model/Bootstrap I

Isidro Castineyra described a bootstrap model for Nimrod.  Highlights of
his talk follow:


   o Nimrod specifies only what happens between nodes.

   o The internal operation of an ``atomic'' node is not Nimrod's
     concern.

   o There are two kinds of locators:  flat and hierarchical.

   o The flat locator of a node is used in Basic Routing (later) to do
     flat routing within the components node of nodes.  This mode of
     routing is used to bootstrap hierarchical routing.

   o The Nimrod part of a hierarchical locator is a sequence of up to
     256 locator elements, where a locator element is a 16-bit string.

   o Hierarchical locator is ``inside'' a node if its Nimrod part is
     both prefixed by the node's locator and longer than the node's
     locator.

   o For a given node and for a given hierarchical locator inside the
     node, the first element following the original node's locator
     identifies a component node.  This 16-bit string is referred to as
     the node's ``local element.''  Therefore, nodes are limited to
     having no more than 216 component nodes.

   o For a given node, the assignment of the values of local element to
     component nodes is independent both of assignment of local elements
     inside the node's subnode and in nodes that subsum the given node.

   o Basic routing is based only on connectivity (i.e., it does not take
     into account considerations of quality of service or service
     restrictions).

   o Basic routing is used for agent discovery and to enable
     communication between agents that reside in different nodes.  The
     advanced routing capabilities of Nimrod are built over basic
     routing.

   o Basic routing is very much like a one-level OSPF. Basic routing is
     built over a flooding protocol which works between the set of
     nodes.  When a message is flooded, every node in the set receives a
     copy of the message which is delivered to the node's
     representative(s).

   o Information flooded includes:  identity of neighboring component
     nodes, what agents the node includes.


Slides from this presentation will be posted to the mailing list.



Nimrod Model/Bootstrap II

Martha Steenstrup described an alternative bootstrap model.  Highlights
of her presentation follow:


   o Besides interaction between nodes, Nimrod specifies interaction
     between agents within a node.  These agents might reside in
     separate ``boxes'' and be connected via IP.

   o Agents need not reside in the node on whose behalf they act.

   o Agents advertise their presence and characteristics using a
     reliable hop-by-hop flooding protocol.  This flooding is used to
     construct a next-hop agent forwarding table using an algorithm
     similar (but not identical) to standard distance vector algorithms.


The slides for this presentation will be sent to the mailing list.



Software Architecture

Charlie Lynn presented the current software architecture for the BBN
implementation of Nimrod.



Path Management Issues

Martha Steenstrup listed alternatives for path setup.


   o Should path labels be globally unique or path unique.

   o Path constructions:  should we use hierarchical routes or
     hierarchical paths.

   o Path repair:  should it be done at any node; at initiator or
     target; between successive hops?