Re: BGP advertise non best routes?

Would as path ignore not cause loops and black holes?

I understand what you want but I'm sure bgp will only offer the best route to that prefix to the routing table, it might be worth experimenting with the as's and see if primary link goes down does your ping get through on the other path?

BR

Tiny

Sent from my iPhone on 3

On 13 May 2012, at 20:07, marc abel <marcabel_at_gmail.com> wrote:

> Thank you for your response john. I may not have explained what I am trying
> to do well enough.
>
>
> what I am talking about is if you have two paths in the bgp table such as
> this:
>
> R3(config-if)#do show ip bgp
> BGP table version is 21, local router ID is 1.1.3.3
> Status codes: s suppressed, d damped, h history, * valid, > best, i -
> internal,
> r RIB-failure, S Stale
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
> * i100.100.1.0 10.1.2.254 0 100 0 500 i
> *>i 10.1.1.254 0 100 0 500 200 i
>
> Your router will only advertise out the route it considers best to its BGP
> peer. So in this case it would only advertise the route through 10.1.1.254.
> What I want is to be able to send both options to the next router in the
> line and then let it choose based on weight or as path or something.
>
> *note I have applied "bgp bestpath as-path ignore" that is why this one
> isn't preferring the shorter AS path.
>
>
>
>
> On Sun, May 13, 2012 at 1:49 PM, john matijevic <john.matijevic_at_gmail.com>wrote:
>
>> Good Afternoon Marc,
>>
>> "Is there any way to force BGP to advertise all of it's routes, even ones
>> it
>> doesn't consider best? "
>>
>> You can use the network statement under the BGP process to advertise
>> the connected networks. For routes learned via another protocol, you
>> can use the redistribute command.
>>
>> Once you have all the routes that you want advertised you can use
>> different filter techniques to advertise or bgp attributes command to
>> prefer one path over another.
>>
>> Hope this helps.
>>
>> Regards,
>> John
>>
>>
>> On 5/13/12, marc abel <marcabel_at_gmail.com> wrote:
>>> Is there any way to force BGP to advertise all of it's routes, even ones
>> it
>>> doesn't consider best? Particularly looking for a way to make an iBGP
>> peer
>>> prefer a different route than it's route reflector.
>>>
>>>
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Received on Sun May 13 2012 - 20:27:53 ART