[f-nsp] Preferred Links via BGP

[chip]

On 3/13/07, Loopback <loopback at ezxyz.com> wrote:
>
> All
>
>
> We would appreciate some ideas for the best method of implementing limited
> traffic engineering via BGP for our current network.  We have two EBGP
> routers in the same physical location with and IBGP connection between
> them,
> each are dual homed to 3 Tier 1 ISP's and single homed to one other ISP.
>
>
>   Router A
>
> A -----------10Mb/s-------------- ISP #1
> A -----------10Mb/s---------------ISP #2
> A -----------10Mb/s---------------ISP #3
> A -----------10Mb/s---------------ISP #10
> |
> |
> |  Router B
> |
> B -----------10Mb/s-------------- ISP #1
> B -----------10Mb/s---------------ISP #2
> B -----------10Mb/s---------------ISP #3
> B -----------10Mb/s---------------ISP #20
>
>
> We currently do not enforce any PBR, our outbound route selection
> algorithm
> is default "shortest AS-PATH"  destination network with the addition of
> "BGP Multi-Path" so that any return traffic to routes with equal AS-Path
> lengths will balance among all the connections with equal cost.
>
>
> We are going to upgrade the bandwidth on the "ISP #1" connection to a GbE
> on
> both routers and leave the others at the current bandwidth.  This will be
> much less expensive connection per Mb/s, for that reason we would like to
> prefer it for the return path for all outbound traffic to any destination
> that does NOT originate from with the AS of one of our other directly
> connected providers.  Our thoughts is that approach will combine both
> routing efficiency and economy.
>
> The question is the best method to accomplish this using BGP, and
> preferably
> without having to coordinate MED's or Community values with our providers.
>
> Looking forward to hearing your opinions.
>
>
> Jack
>
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>


Could just add a pre-pend or 2 to each ISP but #1.  Most of the non-directly
connected networks will likely prefer the shorter AS-PATH.  All your
directly connected ISP's will, most likely, choose you directly, as customer
local-pref is usually set higher than peer.

--chip

-- 
Just my $.02, your mileage may vary,  batteries not included, etc....
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