From: Patrick W. Gilmore (no email)
Date: Mon Nov 03 2008 - 01:26:14 EST
Having skimmed the Sprint / Cogent threads, I saw multiple errors and
lots of really bad guesses. Instead of replying individually, I
thought I would sum up a few facts so everyone was on the same page.
This way when we run off into another 100 post thread, we can at least
-start- from reality (although I would bet serious cash on long odds
we will diverge from it soon enough).
1. Neither Sprint nor Cogent have transit
Both Sprint & Cogent are transit-free networks. (Notice how I
carefully avoided saying "tier one"?) Whether one or both _should_
have transit is not a fact, and therefore outside the scope of this e-
mail, but that neither have transit today is a fact. (And please
don't tell me how Network X has 100 Mbps of transit in Sri Lanka
because they are too lazy to lease undersea cable. If you don't
understand what I am saying here, stop reading now.)
2. The Internet cannot "route around" de-peering
I know everyone believes "the Internet routes around failures". While
occasionally true, it does not hold in this case. To "route around"
the "failure" would require transit. See item #1.
3. Standard transit contracts do not guarantee full connectivity
If you are a Cogent customer, it is very unlikely your contract will
allow you SLA or other credits for not being able to reach Sprint
unless you negotiated something special. I doubt Sprint's standard
contract is much different. Transit contract SLAs end at AS
boundaries. This is because Network A has no control over Network B
and therefore will not give credit if Network B fails. Of course, you
can still sue, threaten to terminate, etc., but the letter of the
contract almost certainly says nothing about packets going beyond your
transit provider's ASN.
4. There is a reason behind ratios which has nothing to do with telco
Hot potato routing + very poor ratios puts much more of the cost on
the receiving network. This is a valid, logical, and costly concern
for receiving networks. The concern can be alleviated by cold-potato
routing through accepting MEDs, anycast, CDN, and other technologies;
to which the receiving network may say they cannot send proper MEDs,
etc. Whether the problem can or should be worked through is not a
fact, though. That this issue has nothing to do with telco "sender-
pays" mentality is. (Of course, the telcos might still have that
mentality, but that doesn't change the facts.)
5. Cogent has been disconnected several times
Cogent has been de-peered (e.g. Teleglobe, L3, Sprint) and/or
performed de-peering themselves (e.g. Telia) multiple times. Cogent
has been disconnected from another network more times & for longer (in
each instance?) than every other transit free network combined for the
last decade. (In fact, if memory serves, for the history of the
Internet - but I'm not quite sure enough to guarantee it as fact.)
Cogent has also de-peered many non-transit-free networks, at least
sometimes without even notifying the peer prior to disconnection.
Whether that makes Cogent the bully-er or the bully-ee is not fact, so
I will not comment on that here.
There are probably other errors I missed while skimming the longer
posts. But this should get us started on a good, clean, factual
footing for future flights of fancy.
-- TTFN, patrick