On the subject of multihoming

Matthew Petach mpetach at netflight.com
Tue Nov 4 16:40:15 CST 2008


On 11/4/08, Colin Alston <karnaugh at karnaugh.za.net> wrote:
>  There is good use in general for a public no-distribute feed but I have yet
> to find such a thing. Is there a reason for that

answering that question is easy.  Yes, there are a number of reasons
that nobody provides one:
1) most people don't want the details of their internal routing policies
    known to outside entities.  Perhaps I pay Level3 for routes, but don't
    want the rest of the world to know it; if I provide a BGP feed, unless I
    very carefully sanitize it before it goes out, it will become clear to
    people outside that there are prefixes seen across the path that would
    not be seen by an ordinary peer.
2) It requires careful filtering to ensure that nobody recieving the feed
    accidentally or intentionally uses the routing information in their
    forwarding table without altering next-hops as appropriate; nobody
    wants to end up carrying unexpected traffic.
3) Requires ongoing support personnel to maintain and keep it up
    and running; while not a huge cost, it nonetheless presents a
    continuous, residual drain on resources that few companies are
    willing to underwrite
4) It would be of limited value, unless it covers a relatively large swath
    of the Internet with relatively good splay; having a BGP feed that
    simply shows a default route from your upstream's upstream's
    upstream wouldn't really give much useful data to work with.
5) Much of the data is already available with a bit of delay from RIS/RIPE
    and routeviews; unless you really need the real-time aspect, you might
    as well just get the data from there.

> or could I bribe my
> datacenter to give me a feed and then create my own public server with some
> el-cheapo Quagga and a bag of rainbows for hope?

I'd recommend OpenBGPd -- it's been scaling much better for me, and
converges about 8 times faster than Quagga on the internal route collectors
I run.

Matt




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