The Routing Over Large Clouds Mailing List Archive by date

["Robert G. Cole" <rgc@qsun.att.com>]

Bruce,

>> If the normal routed path over the NBMA travels thru routers A, B, C and D,
>> where routers B and C are transit routers,  wouldn't this lead to
>> the generation of three seperate "short cut" link layer connections (in the
>> case of a connection-oriented NBMA like ATM) for the same packet?
>> For example, 
>>     - router A receives a packet and determines that it is to be forwarded
>>         to its NBMA interface.  it sends a NHRP request and forwards
>>         the packet to router B,
>>     - router B receives a packet and determines that it is to be forwarded
>>         to its NBMA interface.  it sends a NHRP request and forwards
>>         the packet to router C, etc
>>     - once the NHRP replies return to routers A, B and C, they each establish
>>         their own "short cut" connections to D.
>> 
>> If this is indeed the case, then option (c) above should be removed in favor
>> of one of the remaining two.  Am I missing out on something?
>
>You are missing: rate limiting.  Routers B & C need not transmit multiple
>NHRP request packets.  They can drop NHRP packets which exceed whatever your
>desired rate is.
>
>The benefit of option (c) is that your IP traffic is not delayed until
>address resolution (or worse - VC establishment) has completed.
>

What I was asking was if, by router A forwarding the initial IP packet 
(that initiated the first NHRP request) to the transit router B, 
could this also trigger router B to initiate another NHRP request?

Thanks,

Bob


Robert G. Cole
AT&T Business Multimedia Services, Technical Marketing
rgc@qsun.att.com              +1 908 949 1950 (voice)
attmail!rgcole                +1 908 949 8887 (fax)

AT&T Bell Laboratories
Room 3L-533
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