Re: Outbound Route Filtering

Thanks a lot :)

On Mon, May 18, 2009 at 6:12 AM, Abraham, Tharak <tharakabraham_at_gmail.com>wrote:

> Hi,
>
> ORF is a capability by which your router, R1 as per your diagram advertises
> which prefix it want to recieve from R2 or in other words AS 1 is "sending"
> a prefix-list of what routes it wants, while AS 2 is "receiving" the
> prefix-list of what the downstream neighbor wants.
>
> As per your scenario R2 (AS2), the only additional command required is
> "capability orf prefix-list receive".
> And of course at R1(AS1) we need to specify what prefix we want, in your
> case 172.16.1.0/24 and you send the prefix list which you want with
> "capability orf prefix-list send".
>
> Without send prefix list at R1, R2 will advertise all the networks to R1.
>
> If you configure capabilty orf prefix-list both, then the router will have
> the capability to send and recieve prefixes.(two-way)
>
> If i remember theres a wonderful article in INE blog on this, dont miss
> that !
>
>
> Tharak Abraham
>
>
>
> On Sun, May 17, 2009 at 8:38 PM, CCIE Hunter <cisco.ccie.guru_at_gmail.com>wrote:
>
>> Hi group,
>> R1(AS1)-------------------R2(AS2).
>>
>> R2 have prefix that need to advertise to R1. Then i configured R1 as send
>> mode & prefix-list in & R2 as received mode. Everything working fine &
>> config as follow.
>>
>> R1#sh run | b router bgp
>> router bgp 1
>> no synchronization
>> bgp log-neighbor-changes
>> neighbor 10.1.1.2 remote-as 2
>> neighbor 10.1.1.2 capability orf prefix-list send
>> neighbor 10.1.1.2 prefix-list 20 in
>> no auto-summary
>> !
>> ip prefix-list 20 seq 5 permit 172.16.1.0/24
>>
>> *****
>>
>> R2#sh run | b router bgp
>> router bgp 2
>> no synchronization
>> bgp log-neighbor-changes
>> network 172.16.1.0 mask 255.255.255.0
>> network 192.168.1.0
>> neighbor 10.1.1.1 remote-as 1
>> neighbor 10.1.1.1 capability orf prefix-list receive
>> no auto-summary
>> !
>>
>> But is it possible R2 will advertise prefix & control what prefix to be
>> advertise with ORF feature. means without touching anything at R1(even
>> don't
>> configure send mode) ???
>>
>> And when do we need to use " neighbor x.x.x.x capability orf prefix-list
>> both" ???
>>
>> I already browse at cco doc but still confusing send&receive mode.
>>
>> Please, and appreciate for advice
>> Regards
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
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Received on Mon May 18 2009 - 14:14:57 ART