Internet Exchange Point(IXP) questions

Joe Abley jabley at hopcount.ca
Fri Feb 18 15:28:01 CST 2011


On 2011-02-18, at 14:34, Christopher Morrow wrote:

> On Fri, Feb 18, 2011 at 1:43 PM, Michael K. Smith - Adhost
> <mksmith at adhost.com> wrote:
> 
>> Sorry for the misfire on my last email.  The 206.81.80.0/23 network is assigned to the SIX from ARIN.   In general, we don't want
>> people to announce that space to the DFZ, so the three providers listed above are not filtering their announcements properly.  It is, as
>> others have said, a good idea to announce the exchange block to your customers, but not out to the DFZ.
> 
> why is it a good idea to send this to your customers? the next-hop
> info is surely only useful to your local network? done right it's even
> only relevant to the IX connected router, right? it seems wholely
> unusful to your customers. (to me at least)

Well, except for the reason that Leo mentioned.

The NEXT_HOP in the exchange point subnet will not make it to the customer router. It's not a transitive attribute. The customer will see a NEXT_HOP corresponding to the provider router (or whatever they decide to re-write it as). See RFC 4271 section 5.1.3.


Joe



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