From: Paresh Khatri (Paresh.Khatri@aapt.com.au)
Date: Wed Mar 23 2005 - 22:32:05 GMT-3
Yep, that is pretty much it...
One other thing that is really cool.. you can use the following command on the 'receive' side to see whether it has got your prefix-list 'sh ip bgp neighbors <ip> received prefix-filter'
Cheers,
Paresh.
-----Original Message-----
From: Eric Taylor [mailto:etaylor10@tampabay.rr.com]
Sent: Thursday, 24 March 2005 11:18 AM
To: Paresh Khatri; Group Study
Subject: RE: BGP Prefix-based ORF?
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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