sundar.palaniappan Mon, 07/30/2007 - 12:47
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No. First of all IOS doesn't let you specify the IP address as an option in the update-source command and you would have to specify an interface with the update-source command. Moreover it's not practical to use HSRP address for BGP peering as address doesn't always belong to the same device.


HTH


Sundar

rboldy123 Mon, 07/30/2007 - 12:52
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Thanks for the response - My reason for thinking about it is that I wish the BGP peer to only be established with the device that is actively holding the HRSP VIP !

sundar.palaniappan Mon, 07/30/2007 - 13:05
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While using HSRP address for peering isn't an option BGP offers a wide range of options for redundancy and load sharing. If you can provide more details about your topology and what's that you are trying to achieve we can probably assist you with the configuration.


HTH


Sundar

Edison Ortiz Mon, 07/30/2007 - 12:52
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You are only allowed to source from an interface, not from a virtual address.


While you are allowed to configure the neighbor pointing to the HSRP address, the remote connection will be refused since it will be sending the packet from an invalid IP address.

rboldy123 Mon, 07/30/2007 - 12:55
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This is where I got to - so was hoping for a work-around !


Thanks anyway, after looking into this for a while I didn't think it was possible but just wanted a second opinion.

jbrunner007 Mon, 07/30/2007 - 13:48
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two options come to mind;


create the same anycast loopback address on both possible bgp peers of the third peer, put both in to the IGP, and let the igp determine the best path to each...


or just fully mesh to the loopback address of the peers.


Joe


As Jbrunner007 has mentioned, the only way to peer with HSRP would be with an anycast loopback. Let's say you have 3 routers: R1, R2, and R3. Let's assume all of these are on the same subnet for this example. R1 and R2 will be the HSRP peers and R3 will be the router trying to peer with the HSRP address. (Just putting in the signicant portions for the sake of brevity)


R1

int lo0

ip add 1.1.1.1 255.255.255.255


int gi0/0

ip add 2.2.2.2 255.255.255.0

standby 0 ip 2.2.2.1


router bgp 1

neigh 2.2.2.4 update-source l0


R2


int lo0

ip add 1.1.1.1 255.255.255.255


int gi0/0

ip add 2.2.2.3 255.255.255.0

standby 0 ip 2.2.2.1


router bgp 1

neigh 2.2.2.4 update-source l0


R3


int gi0/0

ip add 2.2.2.4 255.255.255.0


router bgp 2

neigh 1.1.1.1 remote-as 1


ip route 1.1.1.1 255.255.255.255 2.2.2.1




In this case we used a static route to get to the anycast loopback, if they aren't on the same subnet you'd need to rely on an IGP and tune the metrics so that R2 had a worse metric from R3.

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