Re: aads renumbering rumor and implications

[Stephen Stuart]

I don't know about the specifics of ADS, but this question:

>   o does anyone see why the exchange address space needs to be globally
>     routable?

is valid in any case. 

Global announcement of IX address space has caused me trouble in the
past when "remote" maintenance access depends on it; inconsistent
policy with respect to IX prefix announcement caused the path to the
IX prefix to be wildly lossy, while announcement of a non-IX prefix
was much better. We addressed that by making sure that all equipment
was maintained and monitored remotely using non-IX address space
addresses so that there was slightly better control over the
announcement (and over packet-level access to addresses on which
monitoring was permitted).

That said, I think it's still important to have global reachability
for exchange point addresses so that problems like congestion can be
remotely diagnosed. Sometimes the difference in packet loss between a
provider's IX address and some address one hop beyond it is a valuable
clue in tracking down problems; without global routing of exchange
point addresses, such diagnosis would only be possible to those who
distribute the IX prefix within their IGP.

Stephen