No one behind the wheel at WorldCom

Legend speaks of a well known BGP community referred to as 'no export',
which causes people with no direct connections to $carrier to not
have to listen to all that extra junk while still engineering inbound
traffic w/ more specifics for people who peer directly in diverse
locations. Amazing!

Indeed, I know from personal experience the heartbreak of supplying
no-export to a BGP peer who does not honor it, and propagates the
more-specific prefixes that I give them globally.

> 2. Cut-outs for those pesky dot-coms; you know, the ones with the most
> compelling content on the Internet jumping up and down in your face
> with a need to multi-home their /24 to satisfy the crushing global
> demand for such essentials as "the hamster dance."

Ignoring inconsistent-as for a moment, the hamster dance multihoming
doesn't make the parent upstream need to _originate_ anything of the sort.

Presumably inconsistent-as is the only way that a more-specific
announced by a dual-homed customer would get charged to an origin AS
on Tony's list; in such a case (and on reflection, it is much more of
a corner case when inconsistent-as is involved, as you are correctly
pointing out), the parent that provided the address space would need
to originate that announcement if they wanted any of the traffic
toward that prefix to use their network.

Looking at "show ip bgp inconsistent-as," the number of prefixes that
would be charged to Tony's list for AS701 as an origin is certainly
small, if not non-existent.

Ignoring the specifics of Tony's list for a moment, it has been
pointed out in a couple NANOG presentations that the cut-outs
associated with dual-homing (yes, the _propagated_ ones, as opposed to
the _originated_ ones) are major contributors to recent routing-table
growth. Given AS701's footprint, it's hard not to imagine them seeing
more of that kind of thing than most.


The earlier comment made reference to 1221's prestigious and long-held position at the top of the CIDR report.

Rumour has it that the deaggregated set of long-prefix routes advertised by 1221 to its peers and transit providers is there because of the requirement of 1221 to balance inbound traffic from ASes with which 1221 does not directly peer (as in BGP), over an array of random legacy transmission capacity under and around the Pacific. It is not obvious how no-export helps with this general problem (although see draft-ietf-ptomaine-nopeer-00).

[I am not now, nor have I ever been involved in designing or applying routing policy for AS1221, but I have been known to drink the occasional beer with people who have.]


I'm wondering how many folks out there choose not to honor this
community and why. If anyone on the list chooses not to I'd be
interested to hear (either on-list or off) the reasonings behind it.