Sprint v. Cogent, some clarity & facts

Patrick W. Gilmore patrick at ianai.net
Mon Nov 3 00:26:14 CST 2008


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  
"sender-pays"
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





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