BGP Failover problem/issue

[menace212]

Can anyone help with a BGP failover configuration.There are five routers. First there are two ISP routers, we will call them ISP1 and ISP2. Then I have my routers I control,router1, router2, router3. Router1 connects to ISP1(EBGP), router2 connects to ISP2(EBGP), router3 connects to router2(EBGP) and router1(IBGP).

So basically if the route for ISP1 fails, traffic should route through ISP2.I have a sample configuration for router1 but I a bit confused about the configuration for router2, and router3. Does anyone have a better BGP configuration for BGP failover between these routers.
Now router 2 and router 3 are not directly connected...They are connected through an ATM cloud. Do I need another statement in the BGP configuration for router 2 or/and router 3.Becasue router 3 doesn't show the BGP connection in router's ip routing table(show ip route), it only shows the connected subnets. Although when I do a show ip bgp neighbors on router 3, I can see the TCP connection between router 2 and 3.

Keep in mine the networks(.108,110,111) are really intended for the LAN network on router 2. So there is an IBGP connection between router 1 and router 3. It's a little backwards but that's how they want.. So the networks above come from the internet cloud and they come in through router 1 and router 1 sends the traffic across the IBGP link to router 3. If they orginate from a mail server from the router 3 network that's intended to go to the .108 network. The traffic will go through router 3 to router 1 and then out to the internet...I know it's a little confusing, but hopefully you can follow the proposed configurations below. Any suggestions or modifications to the config's below...





Router 1:
Int fastethernet 0/0
description connection to Router 2
Ip address 214.4.105.1 255.255.255.252 secondary
Ip address 214.4.106.2 255.255.255.252

Int fastethernet 0/1
description connection to ISP1
Ip address 10.10.24.1 255.255.255.0

Router BGP 50
No sync
Bgp log-neighbor-changes
Network 214.4.105.0
Network 214.4.106.0
Neighbor 10.10.24.4 remote-as 721
Neighbor 10.10.24.4 route-map ISP-1 out
neighbor 10.10.24.4 route-map ISP-1in in
Neighbor 214.4.106.1 remote-as 50
neighbor 214.4.106.1 route-map router-2 out
Neighbor 214.4.106.1 next-hop-self
No auto-summary

Access-list 1 permit 214.4.106.0
access-list 1 deny any
Access-list 2 permit 214.4.105.0
access-list 2 deny any
Access-list 3 permit 214.4.108.0
Access-list 3 permit 214.4.110.0
Access-list 3 permit 214.4.111.0
access-list 3 deny any


Route-map ISP-1 permit 10
Match ip address 1
Set as-path prepend 721 721 721

Route-map ISP-1 permit 20
Match ip address 2

route-map ISP-1in permit 10
match ip address 3

route-map router-2 permit 10
match ip address 3


Router2:

Current configuration : 1465 bytes
!
version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname router3

!
syscon address 1.1.1.1 password
syscon shelf-id 0
ip subnet-zero
ip cef
!
!
!
!
!
!

!
interface FastEthernet0/0
description to router2
ip address 199.57.22.34 255.255.255.252
duplex half
speed 10
!
interface FastEthernet0/1
description connection to ISP2
ip address 198.26.74.176 255.255.255.0
duplex full
speed 100
!
router bgp 65000
no synchronization
bgp log-neighbor-changes
redistrubute connected
neighbor 198.26.74.177 remote-as 500
neighbor 199.57.22.33 remote-as 50
no auto-summary
!
ip classless
no ip http server

!
line con 0
stopbits 1
line aux 0
line vty 0 4
password dos
login
line vty 5 15
password dos
login
!
end


Router3:

Int fastethernet 0/0
description connection to router 1
Ip address 214.4.105.2 255.255.255.252 secondary
Ip address 214.4.106.1 255.255.255.252

Int fastethernet 0/1
description connection to router 3
Ip address 10.10.13.1 255.255.255.0

Router BGP 50
No sync
Bgp log-neighbor-changes
Network 214.4.105.0
Network 214.4.106.0
Neighbor 10.10.13.3 remote-as 65000
Neighbor 10.10.13.3 route-map router-3 out
Neighbor 214.4.106.2 remote-as 50
neighbor 214.4.106.2 route-map router-3in in
Neighbor 214.4.106.2 next-hop-self
Maximum-paths 2
No auto-summary

Access-list 1 permit 214.4.105.0
acces-list 1 deny any
Access-list 2 permit 214.4.106.0
access-list 2 deny any
Access-list 3 permit 214.4.108.0
Access-list 3 permit 214.4.110.0
Access-list 3 permit 214.4.111.0
access-list 3 deny any

Route-map router-3 permit 10
Match ip address 2
Set as-path prepend 500 500 500

Route-map router-3 permit 20
Match ip address 1

route-map router-3in permit 10
match ip address 3
set metric 10000

 

[baddos]

How are the routers physically connected?

Example:

ISP1 ---Internet--- ISP2
| |
| |
Router1 ---LAN------Router 2
|
|
Router 3

If your router isn't connected to an external peer (isp), then don't run BGP on it. What I would do, is run iBGP between router1 and router2, eBGP between router1 and isp1 and between router2 and isp2. I would run OSPF on all my routers (router1, 2, and 3). Router 1 and 2 would advertise a default route in OSPF.

Now in that configuration router3 will have a fast and tiny routing table, and forward unknown destinations to either router1 or 2. It would be redundant since both router1 and 2 are annoucing the default route. Router1 and 2 would be sharing their external routes via iBGP, so they would know the best route to take when they receive packets from router3. If ISP1 or ISP2 go down, the other ISP will be redundant if you are advertising all your netblocks to both ISPs.

 

[menace212]

ISP1 ISP2
| |
|ebgp |ebgp
| router2
| |
| |ebgp
router1-------router3
ibgp

I'm unable to run ospf on all three routers. Currently router1 and router3 are running ibgp.OSPF is not really an option. What kind of configurations for bgp do you recommend
local pref, weight or modifying the route map above...

 

[mainstreetexpress]

Hi
Are routers 1 2 and 3 in the same AS, as I'm just wondering how you're running EBGP between R2 and R3? If so, is a registered AS or a private AS?

Also are you actually receiving full BGP tables from ISP1 and 2?

 

[baddos]

Why are you running eBGP between R2 & R3? I saw earlier talk about an ATM cloud... Where is this in relation to your diagram?

 

[menace212]

For Mainstretexpress question...
routers 2 and 3 are in the same AS, while 3 is in another AS...I'm running EBGP between R2 and R3. All are private AS.And yes I'm receiving full BGP tables from ISP1 and 2.

For Baddos question....
There is a ATM cloud between R2 and R3, I just didn't include it in the mini diagram...

I at a bit of a loss, because R2 is failing over like it should....I'm unable to ping any networks in the ISP cloud from R3...And when R1 fails it bounces over to R2 but fails to route traffic to R3.What gives...