Re: [rrg] Locator

jnc@mercury.lcs.mit.edu (Noel Chiappa) Wed, 13 May 2009 00:12 UTC

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Date: Tue, 12 May 2009 20:13:43 -0400
From: jnc@mercury.lcs.mit.edu
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Subject: Re: [rrg] Locator
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    > From: Fred Baker <fred@cisco.com>

    > RFC 1992 would have it name a transport connection endpoint - the
    > underbelly of an application.

Ah, no. To quote RFC-1992:

  "A locator ... identifies a location in an internetwork.  Nodes and endpoint
  are assigned locators. Different nodes have necessarily different locators.
  A node is assigned only one locator. Locators identify nodes and specify
  *where* a node is in the network. Locators do *not* specify a path to the
  node."

One also needs to be aware that in this document, "node" means 'network
region', not 'host/router', as it is commonly taken to mean in networking:

  "A node represents a region of the physical network.  The region of the
   network represented by a node can be as large or as small as desired: a
   node can represent a continent or a process running inside a host.
   Moreover .. a region of the network can simultaneously be represented by
   more than one node."

(In the next section of the document, "node" is very precisely defined to mean
'map element' - from the node/arc terminology of graph theory, since maps are
graphs - the above is just a 'starter definition'.)

       Noel