What peering means [was Re: BBN Peering issues]

Alex Bligh amb at gxn.net
Thu Aug 13 20:35:49 UTC 1998


> | Whether or not they announce non-(Sprint)-customer routes, such as AS1?
> But Alex, you know that many providers would be delighted to
> filter out peers' routes on your behalf, as well as not announce
> you to their peers.  Yet they still charge you money, no?

Yeah, but this is a semantic argument. I used the word 'peering'
as meaning announcement of your own customer routes only, and
expecting those routes only to be reannounced to BGP speaking
customers; this is the normal use in the term 'peering point'.
Equally valid is the definition meaning 'route exchange for
no money, networks being of equivalent size blah blah blah'
(I remember when ANS were charging $100/month for peering, or,
urm, may be it wasn't peering after all then). Equally valid
is the use 'peering' meaning running a BGP session and exchange routes.

There are 3 main differences as far as I can see between traditional
peering connections, and traditional BGP speaking customer transit:
1. Historically, peering has been free, transit hasn't
2. Historically, peering has been provided over open-port or nearly
   open port lines (MAEs etc), transit hasn't in the main. One
   could argue that peering has also essentially been best effort.
3. Historically, peering has meant you were only announced customer
   routes, and transit has meant you got all routes. And similarly
   for announcements.

(2) is already to changing (private peering). (1) has changed
in the sense that it's not free to everyone any more, i.e.
is there is black as well as white, but not much grey (we'll
peer if you pay) yet. (3) as you say already comes in many shades
of grey with innovative partial transit and route swap arrangements.

One of the problems with these arguments is people always seem to
mix up (a) monopoly exploitation (b) people making political decisions
who don't understand routing etc. etc. on the one hand, with, on
the other (c) change resistance, (d) outdated dogma etc. etc., (f) lack
of appreciation that the internet is a commercial environment etc. etc.,
which tends to weaken the arguments of those arguing (a), (b) etc. by
conflation with know-not-much'es arguing (c), (d) ... [No, this is
not a comment about BBN peering issues, it's a comment about evolving
peering models & settlement]

> This raises an interesting diagnostic issue which some people
> run into from time to time when hunting down weird routing problems:
> how can a third party know what is being announced and
> thrown away (or just not selected), versus what is not being
> announced at all?

show ip b neighbor <blah> received-before-filters

on your IOS 13.0 router with a looking-glass behind it? :-)

Alex Bligh
GX Networks (formerly Xara Networks)

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