[Xorp-users] BGP conditional route advertising

mihai at duras.ro mihai at duras.ro
Fri Sep 1 03:24:32 PDT 2006


1. I don't know if I'm that good with coding in regard to Xorp but I'll
give it a try.

2. I was taking about the following case:

Provider --.> Upstream 1 ISP  --> Telia

same Provider --> Upstream 2 ISP --> Level-3 let's say

Telia will always return traffic to you via Upstream 1 ISP...but let's say
you'd like to use one link for all traffic (download and upload) and the
other one only as backup (financial reasons)

That was what I was pointing at:)

3. Thought about the script option..but I was looking more at something
built-in...looks like I'll have to document myself and add it to the
existing code.


> On Fri, Sep 01, 2006 at 11:56:21AM +0300, mihai at duras.ro wrote:
>> I'll try adding a feature request then.
>>
>> Prepending is sometimes not enough.
>>
>> For example some upstream providers will always place a higher weight,
>> local pref,etc on a route received from a certain peer and thus render
>> the
>> as-path prepend unusable.
> Certainly. I'd say just about everyone places a
> higher local preference on their own customers,
> but that lpref won't be visible beyond your
> upstream so just about everyone else on the
> Internet will choose the best route based on the
> shortest AS-PATH.
>>
>> What I want is:
>>
>> Announce my route over ISP1 while ISP1 is online (and don't receive any
>> traffic on the backup ISPs).
>> If ISP1 down then announce via ISP2.
>> If ISP2 down..and so on.
> You could probably do this via some form of shell
> script that polls to see if ISP1 is down or not
> and then add an advertisement via ISP2.
> or buy a Cisco.. or do some XORP coding :)
>
> Regards,
>    Kristian.
>
>
>> > On Fri, Sep 01, 2006 at 11:25:01AM +0300, mihai at duras.ro wrote:
>> >> Hello,
>> >>
>> >> Sorry if this has been asked before but I had no luck while
>> google-ing
>> >> for
>> >> it.
>> >>
>> >> Does XORP support BGP conditional route advertising as Cisco does
>> with
>> >> the
>> >> advertise map per-neighbor command ?
>> > As far as I know it does not, but it would indeed
>> > be a nice feature. You could add a feature request
>> > at http://www.xorp.org/bugzilla/index.cgi with a
>> > small description of what you want :)
>> >
>> >> I'm searching for a solution to advertise some prefixes on a backup
>> link
>> >> only if the main link goes down (the default gateway is no longer
>> >> received
>> >> on it with an AS-PATH of the neighbors AS)
>> > Isn't prepending your as-path enough?
>> >
>> > Regards,
>> >     Kristian.
>> >
>> > --
>> > Kristian Larsson                                   KLL-RIPE
>> > Network Engineer                      Net at Once [AS35706]
>> > +46 704 910401			     kristian at spritelink.se
>> >
>>
>>
>




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