The Routing Over Large Clouds Mailing List Archive by date

[Grenville Armitage <gja@thumper.bellcore.com>]

[Andy Malis wrote...]
[Andy Malis wrote...]
>>Attempting to clear up the confusion ... here is how the transition will
>>Attempting to clear up the confusion ... here is how the transition will
>>work:

	[...]

The part I'm not seeing is the evolution of rfc1577-only hosts.
The transition plan seems to assume that hosts must be upgraded
to 'talk NHRP' if they want the benefits. Yet it occured to me
that in an LIS of X hosts and 1 ARP Server (and X >> 1) it
that in an LIS of X hosts and 1 ARP Server (and X >> 1) it
would be useful to also allow ARP Servers to be upgraded to
would be useful to also allow ARP Servers to be upgraded to
resolve host queries using NHRP. This (I think) would allow
rfc1577-only hosts to use cut-through VCs before having complete
local NHRP code. This is not quite the same as adding NHRP to the edge 
routers of 1577-only LISs.

Resolution sequence for non-NHRP hosts becomes:

      Local Host --> resolves addr from local cache
           |                   |
       (cache miss)           /|\
	ARP_REQUEST            |
	ARP_REQUEST            |
           |               ARP_REPLY
           |               ARP_REPLY
          \|/                  | 
           |                   |
      ARP Server ---> resolves addr from local cache
      ARP Server ---> resolves addr from local cache
           |                   |        
       (cache miss)           /|\
        NHRP request           |
           |               NHRP response
          \|/                  |   
           |                   |
      Nearest NHS ---> resolves addr from local cache
           |                   |        
       (cache miss)           /|\
        NHRP request           |
           |               NHRP response
          \|/                  |   
           |                   |
      Next NHS ---> resolves addr from local cache

etc.

Of course, this is only of relevance if people think there will
be rfc1577-only hosts out there :-)

cheers,
gja