10-14-2007 05:01 AM - edited 03-03-2019 07:09 PM
I attached a diagram of a network I'm working with. It is an eWan connection and connecting to the ISP currently works but my BGP may be a little messed up.
ISP Assigned me 20.10.10.0\24
I need to make sure my outbound and inbound traffic is load-shared as much as possible but I dont know if my current config will work.
I'm running OSPF as an IGP and BGP out to the ISP. The ISP is advertising about 120,000+ BGP routes to R1 & R2.
I know I need to create some route-maps but not sure how to properly set them up.
R1:
Int vlan 123
description "Connect to ISP"
ip address 15.10.10.133 255.255.255.248
int g1/1
description "connection to ISP"
switchport access vlan 123
switchport mode access
int vlan 300
description "ISP Assigned IP Block"
ip address 20.10.10.1 255.255.255.0
int g1/20
description "connection between R1 & R2"
switchport trunk encap dot1q
switchport mode trunk
Int g1/21
description "Connection to R3"
switchport trunk encap dot1q
switchport mode trunk
Router ospf 10
network 20.10.10.0 0.0.0.255 area 0
Router BGP 100
no synchronization
neighbor 15.10.10.129 remote-as 200
neighbor 20.10.10.4 remote-as 100
no auto-summary
______________________________________
R2:
Int vlan 123
description "Connect to ISP"
ip address 15.10.10.141 255.255.255.248
int g1/1
description "connection to ISP"
switchport access vlan 123
switchport mode access
int vlan 300
description "ISP Assigned IP Block"
ip address 20.10.10.4 255.255.255.0
int g1/20
description "connection between R2 & R1"
switchport trunk encap dot1q
switchport mode trunk
Int g1/21
description "Connection to R3"
switchport trunk encap dot1q
switchport mode trunk
Router ospf 10
network 20.10.10.0 0.0.0.255 area 0
Router BGP 100
no synchronization
neighbor 15.10.10.137 remote-as 200
neighbor 20.10.10.1 remote-as 100
no auto-summary
_____________________________________
R3:
Int Vlan 300
ip address 20.10.10.2\24
Int g1/1
description "Connection to R1"
switchport trunk encap dot1q
switchport mode trunk
Int g1/2
description "Connection to R2"
switchport trunk encap dot1q
switchport mode trunk
Router OSPF 10
network 20.10.10.0 0.0.0.255 area 0
10-19-2007 06:59 AM
Another way to specify OSPF routes to be imported into BGP is by using route redistribution. The default is for all routing redistribution to be disabled. I didn't find anything that stood out as being misconfigured at this point. can you send the following to me:
sh ip bgp nei ISP advertise
sh ip bgp nei ISP routes
http://www.cisco.com/en/US/tech/tk365/technologies_configuration_example09186a008009425c.shtml#t1
10-19-2007 11:01 AM
Hi,
You are nowhere redistributing routes in the posted configuration. How have you seen the received routes and are redistrbuted in OSPF.
Please share the exact config alongwith problem statement.
10-22-2007 09:08 AM
I wouldn't go redistributing 120,000 BGP routes into OSPF, thats going to be a world of pain for your OSPF routers :-(
Why don't you redistribute default routes from both R1 and R2 into the OSPF domain as External Type 1 routes? This way, each internal OSPF router will use the 'closest' router (R1 or R2) for external routes. If you advertise you internal routes to your ISP identically on both R1 and R2, you can 'hope' that the ISP will utilise both links for inbound traffic to your AS, but it depends on there set-up.
Hope this helps
Dazzler
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