Had in interesting conversation with a transit AS on behalf of a customer
where I found out they are using communities to raise the local preference
of routes that do not originate locally by default before sending to a
other larger transit AS's. Obviously this isn't something that was asked
of them and it took a few days to find since the customer is not a large
company and neither them nor my company has a link or business relationship
with the AS in question. This seemed strange to me for obvious reasons,
but I was curious if anyone else was doing this and why. You obviously
cannot use prepend to affect transit traffic again for obvious reasons.
MED is a weak metric but it at least only affects traffic that was already
going to transit your AS. The larger transit AS was favoring a lower
bandwidth link for the customer and causing them to drop packets
mysteriously. Just wondering if this practice seemed as strange to others
as it does to me.
