[nsp] BGP tweaking possibility

[Tony Tauber]

On Tue, 15 Jul 2003, Charles Sprickman wrote:

> From: Charles Sprickman <spork at inch.com>
> To: Gerald <gcoon at inch.com>

Do you guys work together or something?

> On Tue, 15 Jul 2003, Gerald wrote:
>
> > I have a 2 Mb commit for one Internet connection and I would like
> > to send my first 2 Mb of traffic out that line and the rest out
> > another connection.
>
> You won't be able to be that exact...

Very true.  There's no mechanism to cut traffic up by volume.
The best you'll be able to do is trial and error unless you get
into some kinky netflow stuff.  Even then, you're making a config
based on some statistics, not causing the router to make a decision
based on load.

> > What is the best way to go about doing this?
>
> I know one of those providers will let you tweak things with
> communities in a very fine-grained fashion.  I would have a look at
> perhaps just taking routes from their direct peers and ignoring
> their transit connections.  This could also possibly net you a
> discount if you promise not to use their transit at all.

You might do better to take both transit and non-transit routes and
depreference the transit ones so they're only used in case of a
failure of the preferred path.

> That's just an idea.  Don't ask me how to set any of that up as I've
> never touched communities.  Not that I don't want to or anything...

You could act on the communities on routes that you're hearing from
others, which would affect outbound traffic.  Some providers will
act on communities you send to them in order to change the preference
of a route relatively up or down somewhat which will affect inbound
traffic.

In all seriousness, there's quite a bit to this topic and it doesn't
lend itself to elaboration in an email.  I suggest getting a book on
BGP and/or searching for BGP traffic engineering or BGP load sharing
on Cisco's web site, on google, etc.  (Ignore pages that involve MPLS
which is often mentioned in the same breath with traffic engineering
but is not relevant here.)

Tony

>
> Charles
>
> > A little about my setup: Dual homed FE's in the same Cisco 7206
> > router with BGP sessions established to both connections.
> >
> > Thanks in advance for any help or suggestions.
> >
> > Gerald