[ppml] ppml 2002-7

CJ Wittbrodt cjw at groovy.com
Tue Feb 11 12:04:45 EST 2003

    > There is little credible engineering reason to deny allowing an
    > organization to own a small public block.  I have not seen any research
    > done that would suggest that doing this would impact routing table size.
    The routing table size isn't really the main argument against this.  It's 
    the _structure_ of the routing table, in terms of ability to aggregate.
    Right now, ARIN only allocates /20 and longer blocks.  This means that 
    service providers could filter routes they receive on this boundary (in 
    ARIN blocks anyway) to help control the size of the routing table in their 
    network.  If ARIN allocates longer blocks, this ties the hands of service 

Don't you mean ARIN allocates /20 or shorter length blocks?  

Anyway, I have been doing some work with some students at UCLA.  The current
results say that around 48% of allocated blocks are advertised identically 
to how they're allocated (same prefix length, not fragments).  Around
40% of the allocated blocks are advertised in one or modes of fragmentation
(combinations of aggregates and fragments). This means that an ISP could
get great benefit from being able to filter out the fragments of shorter
provider blocks.   I am presenting this at NANOG so fee free to look at my 

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