aggregation tool wanted

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1

i have a perl script which takes in the form

    133.10.0.0
    133.11.0.0
    155.162.0.0/15
    155.164.0.0/14

and tells me that i can aggregate the first two into a /15.

unfortunately, the actual data as paths can differ

    133.10.0.0 2914 2907
    133.11.0.0 2914 2907 2501
    155.162.0.0/15 2914
    155.164.0.0/14 2914

so, what i would like is a tool which takes something like the latter syntax
and tells me what the origin ass could aggregate. i.e. i am specifically
not inclined to proxy aggregation at this point.

Maybe CIDRadvisor does this, but I have been unable to make it do so.

randy

2

unfortunately, the actual data as paths can differ

    133.10.0.0 2914 2907
    133.11.0.0 2914 2907 2501
    155.162.0.0/15 2914
    155.164.0.0/14 2914

so, what i would like is a tool which takes something like the latter syntax
and tells me what the origin ass could aggregate. i.e. i am specifically
not inclined to proxy aggregation at this point.

So in this case, all you'd get back is:

     133.10.0.0 2914 2907
     133.11.0.0 2914 2907 2501
     155.162.0.0/15 2914
     155.164.0.0/14 2914

because the origin AS for each block couldn't aggregate the above blocks
further?

correct.

What is CIDRadvisor? A lookup in some search engines doesn't turn up
anything...

part of RAToolset

randy

3

I once started a project that would do this, which would
allow realtime aggregation by speaking ebgp to a router. I've not had
time to play with it too much, but it does bring up a bgp session and
receive routes properly.

  If I ever finish it, I'll run it and put up a telnet/http interface
to it.

  I would also check out Tony Bates CIDR report, as you can do
interesting things with that data, it will tell you if you can
aggregatte better.

  - jared

4

Randy Bush (randy@psg.com) on November 28:

i have a perl script which takes in the form

    133.10.0.0
    133.11.0.0
    155.162.0.0/15
    155.164.0.0/14

and tells me that i can aggregate the first two into a /15.

unfortunately, the actual data as paths can differ

    133.10.0.0 2914 2907
    133.11.0.0 2914 2907 2501
    155.162.0.0/15 2914
    155.164.0.0/14 2914

so, what i would like is a tool which takes something like the latter syntax
and tells me what the origin ass could aggregate. i.e. i am specifically
not inclined to proxy aggregation at this point.

Maybe CIDRadvisor does this, but I have been unable to make it do so.

CIDRadvisor requires aut-num's to be populated to figure out differing
as paths. Given the state of aut-num's in IRR, it is not a very useful
tool.

One could use as paths from a BGP route table dump. But that is only
an estimate, as two routes flap the as paths may diverge differently.

randy

Cengiz