Re: BGP multihoming issue

yup , I seee in bgp neighbour advertised routes 1.1.0.0/23 to ISP2 even when
my link to ISP1 is down

On Sun, Dec 6, 2009 at 11:56 AM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> Are you sure you are actually advertising the right networks and that they
> are both getting to the other side on ISP2 when things are working
> properly? If you try to advertise "network 1.1.1.0 mask 255.255.254.0" I
> don't believe that will work because the actual route in your RIB would be
> 1.1.0.0/23 correct? I would start with a phone call with ISP2 when BOTH
> links are up. They should be seeing both routes in their BGP table, one
> from you and one from ISP1. One of course will be preferred over the other,
> but you need to see if it is getting there at all first.
>
> On Sun, Dec 6, 2009 at 12:55 AM, jack daniels <jckdaniels12_at_gmail.com>wrote:
>
>> Hi guys,
>>
>> I have a scenario where customer connects to 2 diffrent ISP. Customer has
>> taken a block of IP ADDRESS from APNIC ( lets says 1.1.0.0/23)
>>
>> Now via ISP1 I advertise 1.1.0.0/24 and 1.1.1.0/23<<<<<<Primary for
>> 1.1.0.0/24 and secondary for 1.1.1.0/24
>>
>> Now via ISP2 I advertise 1.1.1.0/24 and 1.1.1.0/23<<<<<<Primary for
>> 1.1.1.0/24 and secondary for 1.1.0.0/24
>>
>> ISSUE - when I shut down the link of ISP1 then my 1.1.1.0/24 works but MY
>> 1.1.0.0/24 SUBNET IS NOT GOING THROUGH ISP.
>> WHEN I CALLED ISP2 they say we see 1.1.0.0/23 VIA ISP1 STILL.
>> <<<<<<<<<<POINT 1
>>
>>
>> when we no shut the link to ISP1 then ISP2 say THEY RECIVE 1.1.0.0/23FROM
>> customer connected to ISP2.<<<<<<POINT 2
>>
>>
>> Can some one help me with this issue or if some one has seen this issue in
>> past ,,,,, why ISP2 is still recieving route from ISP1 when customer LINK
>> to
>> ISP1 is shutdown and
>> why we are not preffering route for 1.1.0.0/23 from customer conneted to
>> ISP2/
>>
>> Regards
>>
>>
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>
>
> --
> Regards,
>
> Joe Astorino CCIE #24347 (R&S)
> Sr. Technical Instructor - IPexpert
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Received on Sun Dec 06 2009 - 12:04:15 ART