Sprint's route filters and Europe
Daniel.Karrenberg at ripe.net
Tue Jun 4 08:04:40 UTC 1996
> "Alex.Bligh" <amb at Xara.Net> writes:
> Sorry I wasn't clear. If you have a /19 allocated in the RIPE database then
> for obvious reasons you have to put a /19 route (not a /18) route in the
> RIPE database. To get ANS to accept this you have to announce a /19 route
> for this. This got filtered by Sprint.
OK so far.
> Before Sprint's (much welcomed - thanks Sean) change of heart, you could
> get around this if you were the lower /19 in the block by also making
> a /18 advert. As the other half of the /18 was unused normally, this
> makes no difference to anyone except those in the /19 suddenly get
> Sprint connectivity.
Since this means announcing routes to address space not allocated to you
it is dubiuous to say the least.
> Actually it was likely to be of benefit to
> any future holder of the upper half of the /18 as that would have
> been the only way they would have gained Sprint connectivity (effectively
> the holder of the lower half gives them partial transit to the point
> where the upper /19 advert hits the /18 route to Sprint). This possibly
> slightly naughty but oh-so-tempting hack would have meant that European
> local IRs were likely to announce a /18 and a lower /19, and an upper
> /19 rather than just two /19s. So Sprint would see one /18 and get
> suboptimal routing, everyone else would see 3 adverts rather than 2.
> Hope that makes sense.
Technically I understand what you are saying.
Whether "it makes sense" is another matter.
> Anyway, all sorted out now Sprint have changed their policy. Glad
> the world has seen sense (i.e. RIPE and Sprint have agreed on the
> same size - whether it was /18 or /19 didn't matter to me, just
> as long as it was consistent).
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