Re: BGP backdoor

That's also how I understand it, but in my case RIP does NOT replace the
eBGP route.

Without backdoor command, also the eBGP is preferred (this we would expect)

thanks

On Fri, Sep 3, 2010 at 7:52 AM, Yemi Oshunkoya <yzmar4real_at_hotmail.com>wrote:

> The way I understand it, ebgp will always have a better route than rip cos
> of admin distance (20 versus 120). When bgp backdoor is configured, it
> allows the Rip route to replace the ebgp route when its not available. try
> removing the backdoor command and observe the behaviour
>
>
> Hth
> Sent from my BlackBerry wireless device from MTN
>
> -----Original Message-----
> From: selamat pagi <ketimun_at_gmail.com>
> Date: Fri, 3 Sep 2010 05:39:43
> To: <ccielab_at_groupstudy.com>
> Subject: BGP backdoor
>
> Trying to understand the usage of backdoor command in BGP.
>
> This is my Lab-setup. With the neigbors-loopbacks configured as backdoor,
> I
> would expect to see CE7 lo on CE8 as a RIP-route.
> But I still get the eBGP route vie PE.
>
> ------------------------------------RIP ----------------------------------
> |
> |
> CE7 -- eBGP --- PE2 --- MPLS --- PE5 -- eBGP -- CE8
>
>
> CE7
> interface Loopback0
> ip address 10.5.7.7 255.255.255.0
>
> router bgp 200
> no synchronization
> bgp router-id 10.5.7.7
> bgp log-neighbor-changes
> network 10.5.7.0 mask 255.255.255.0
> network 10.5.8.0 mask 255.255.255.0 backdoor
> neighbor 10.5.27.2 remote-as 100
> neighbor 10.5.27.2 allowas-in
>
>
> CE8
> interface Loopback0
> ip address 10.5.8.8 255.255.255.0
>
> router bgp 200
> bgp router-id 10.5.8.8
> network 10.5.7.0 mask 255.255.255.0 backdoor
> network 10.5.8.0 mask 255.255.255.0
> neighbor 10.5.58.5 remote-as 100
> neighbor 10.5.58.5 allowas-in
>
>
> R8#sh ip route
> 158.5.0.0/32 is subnetted, 1 subnets
> B 158.5.6.6 [20/0] via 10.5.58.5, 14:53:51
> 10.0.0.0/24 is subnetted, 5 subnets
> C 10.5.8.0 is directly connected, Loopback0
> B 10.5.7.0 [20/0] via 10.5.58.5, 00:00:06 <-- would expect to
> get this via RIP
> R 10.5.27.0 [120/1] via 10.5.78.7, 00:00:18, Vlan78
> C 10.5.58.0 is directly connected, Vlan58
> C 10.5.78.0 is directly connected, Vlan78
>
>
> What do I miss here ?
>
> Thanks, keti
>
>
>
>
> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#bgpbackdoor
>
>
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Received on Fri Sep 03 2010 - 08:00:36 ART