From: robbie (robbie@packetized.org)
Date: Wed Mar 23 2005 - 22:38:16 GMT-3
I think I asked this selfsame question about 6-7 months ago on the list.
From what I can tell, there is an error in the documentation, and your
example is correct. I've only played around with it in the lab, but in a
very large environment, it seems like it would be pretty nice to be able
limit the number of updates.
robbie
Eric Taylor wrote:
> Ok, is this how it would look on the send side?
>
> ip prefix-list WHATEVER seq 10 permit 192.168.1.0/24
> !
> router bgp 100
> address-family ipv4 unicast
> neighbor 172.16.1.2 remote-as 200
> neighbor 172.16.1.2 ebgp-multihop
> neighbor 172.16.1.2 prefix-list WHATEVER in
> neighbor 172.16.1.2 capability orf prefix-list send
> !
>
> And the receive side knows not to advertise 192.168.1.0/24 to me?
>
> If this is how it is implemented, would be nice if they added that in the
> doc cd.
>
> Thanks for replying,
> Eric
>
> -----Original Message-----
> From: Paresh Khatri [mailto:Paresh.Khatri@aapt.com.au]
> Sent: Wednesday, March 23, 2005 8:11 PM
> To: Eric Taylor; Group Study
> Subject: RE: BGP Prefix-based ORF?
>
>
> Hi Eric,
>
> Yeah, I've used this stuff...
>
> You can name the prefix-list anything you like; FILTER is just an example.
> You don't reference the prefix-list within the 'neighbor capability' command
> but if you have an inbound prefix-list configured (on the neighbor
> configured for 'send'), that will be the prefix-list that is sent to the
> peer configured for 'receive' so that it can apply it as part of its
> outbound route filtering...
>
> HTH,
> Paresh.
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Eric Taylor
> Sent: Thursday, 24 March 2005 11:00 AM
> To: Group Study
> Subject: BGP Prefix-based ORF?
>
>
> Hey Group,
> Anyone ever implement or test this feature?
>
> http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122
> t/122t4/ftbgporf.htm
>
>>From what I gather from the link above, this is used to tell a remote router
> to stop sending you updates of specific prefixes. This way you don't have to
> filter them and waste cycles on them at your router with filters.
>
> Do you always use the prefix-list named FILTER?
>
> In the bgp configuration, I can't tell how they are actually referencing
> that particular prefix-list.
>
>
> Router-A Configuration (Sender)
>
> The following example creates an outbound route filter and configures
> Router-A (10.1.1.1) to advertise the filter to Router-B (172.16.1.2). An IP
> prefix list named FILTER is created to specify the 192.168.1.0/24 subnet for
> outbound route filtering. The ORF send capability is configured on Router-A
> so that Router-A can advertise the outbound route filter to Router-B.
>
> ip prefix-list FILTER seq 10 permit 192.168.1.0/24
>
> !
>
> router bgp 100
>
> address-family ipv4 unicast
>
> neighbor 172.16.1.2 remote-as 200
>
> neighbor 172.16.1.2 ebgp-multihop
>
> neighbor 172.16.1.2 capability orf prefix-list send
>
> exit
>
>
> Router-B Configuration (Receiver)
>
> The following example configures Router-B to advertise the ORF receive
> capability to Router-A. Router-B will install the outbound route filter,
> defined in the FILTER prefix list, after ORF capabilities have been
> exchanged. An inbound soft reset is initiated on Router-B at the end of this
> configuration to activate the outbound route filter.
>
> router bgp 200
>
> address-family ipv4 unicast
>
> neighbor 10.1.1.1 remote-as 100
>
> neighbor 10.1.1.1 ebgp-multihop 255
>
> neighbor 10.1.1.1 capability orf prefix-list receive
>
> end
>
>
> TIA,
> Eric
>
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-- robbie at packetized dot org <short sig army - one line sigs since 1993>
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