Subject: draft-ietf-isis-dyname-01.txt

From: Jeff Learman <[email-masked]>
Date: Tue, 06 Jul 1999 11:29:33 -0400

Please forgive me for joining this discussion late in the game,
but let me add some considerations.

Admittedly, putting host names in LSPs is a nifty idea,
and is a simple solution to a practical problem.

However, name-to-address mappings are relatively static and
are not necessary for the operation of the routing protocol.
Do we think it is wise to add information to be stored in every
router in order to have a rarely used but reliable copy of this
information?  The principal reason for using IS-IS to propagate
this information is "because it's there".

Just becuase IS-IS is a good reliable means for propagating information
does not imply that it is the appropriate mechanism for flooding
all information that would be useful to flood.  Noted, the information
in this case is added to assist in maintaining the routing protocol.

But is that the end -- is the host name of a router sufficient information?
We also want information like the manufacturer, the physical location,
and the contact person responsible for the router.  Should this information
also be flooded and required to be stored by every IS in the area or
domain?  Adding unnecessary options to LSPs is particularly troublesome
in SONET networks, where most systems are routers and very few are end
systems.  Exacerbating this, the max LSP size is  512 bytes thanks to
an unfortunate choice of MTU size on SONET links.

My guess is that the host name alone takes little enough space and
adds sufficient value that it is worth serious consideration, and that
the others may be past the point of diminishing returns.  I suggest that
at least, the document should mention this tradeoff and justify it.

I recommend that the option not be required to be present in LSP zero,
because that will affect other limitations that are based on the
max LSP size and information that is required in LSP zero.  It is not
required for the IS-IS protocol to operate properly, and therefore
can appear in any LSP.

Regards,
Jeff
____________________________________________________________________

  Jeff Learman                           Internet:     [email-masked]
  Engineering Manager                    Voice:     (734)-975-7323
  ONE (Open Networks Engineering, Inc)   Fax:       (734)-975-6940
  2725 South Industrial Pkwy, Suite 100
  Ann Arbor, MI  48104  USA
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