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New Member

Static default route with BGP recevied default route

Hi guys;

I have a problem and i can't know how to search or solve it.

My network diagram is attached, please check it first.

Second, I have a multihomed BGP with two ISPs, I received from both ISP default route through BGP.

Now i have two types of IPs as follow:

1- My own prifixes which registered with my AS.

2- IPs bought from ISP2.

I have two network, the first one will contain my own prefixes, and second will contain my ISP2 prifixes. so to go to internet i need to static default route to the ISP2 and that's fine, now the problem that the second default route i received from both ISP no in my routing table however if i show ip bgp i see that i receive them, but because of Administrativ distanc it disappear and prefered the statis default route.

so now one network is online and the second network which contain my own IPs is down, offcourse this second network i need it to routed to my ISP1 via bgp and when ISP1 go down, go through ISP2, and i do this using weight and as-path prepend.

Thanks

Everyone's tags (5)
1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Static default route with BGP recevied default route

Hi Nidal,

With PBR option, you config route-map match your own prefix and set next hop to ISP 1, and ISP 2 when ISP 1 IP is not reachable. Apply the route-map to interface facing to network1. PBR will be processed before routing.

With VRF option, you put interface of network1 and ISP1 in VRF1, so it will have separate routing table. Under the vrf1 You config a static default with higher AD, and next hop pointing to ISP2 in global routing table. This will be used when you lose default from ISP1. Because VRF crests separate routing table, so netwoek1 will use default route in vrf1 to ISP1 as primary, the network2 will use ISP2.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

8 REPLIES
Cisco Employee

Re: Static default route with BGP recevied default route

Hi Nidal,

Is the static default configured on your gateway? If I understand it, you want traffic source from network2 route through ISP2; traffic source from network1 route through ISP1, but use ISP2 as backup. Is that accurate? In that case, if you have 2 Internet gateway router, it will be easier. If it is one Internet gateway dual home to 2 ISP, you might need to use PBR or use separate VRF to achieve your goal.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

New Member

Re: Static default route with BGP recevied default route

Hi Lei Tian;

I just have one border router connected to both ISP, and yes i have a static default route to pass the traffic through ISP2 from the network that have prifixes bought from ISP2,

and i received from both ISP default route through BGP, so how can make my own prifixes to go through ISP1 as a priary and when ISP1 go down, must go to ISP2 as a backup ...

what do you mean about PBR or VRF, could you help me please ?

Thanks

Cisco Employee

Re: Static default route with BGP recevied default route

Hi Nidal,

With PBR option, you config route-map match your own prefix and set next hop to ISP 1, and ISP 2 when ISP 1 IP is not reachable. Apply the route-map to interface facing to network1. PBR will be processed before routing.

With VRF option, you put interface of network1 and ISP1 in VRF1, so it will have separate routing table. Under the vrf1 You config a static default with higher AD, and next hop pointing to ISP2 in global routing table. This will be used when you lose default from ISP1. Because VRF crests separate routing table, so netwoek1 will use default route in vrf1 to ISP1 as primary, the network2 will use ISP2.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

New Member

Re: Static default route with BGP recevied default route

Thanks Lei Tian, i understand you and you are fully right.

i will test it tomorrow and back to you with the result ..

but another question, now we control the traffic that orignated from my AS using PBR or VRF, how about control the traffic coming in to my AS? is AS-PATH will help if i use PBR or VRF? however you said that the PBR table become before routing table.

Regards

Cisco Employee

Re: Static default route with BGP recevied default route

Hi Nidal,

As-path can be used to control route in both direction. With PBR or VRF, you won't be able to control the egress direction using as-path, but if you use as-path for ingress route control, it is fine.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

New Member

Re: Static default route with BGP recevied default route

Hi Lei;

I test with PBR and working fine with primary and failover, but i have a little problem, when the primary link down, it take up to 30 sec to go through the backup link, however when the primary link back up it return without any delay and that good, so how can i configure the failover time to be 3 sec just from primary to backup without modify the return time from backup to primary.

My configuration:

Access list for my subnets

route-map to match the subnets and set the next-hop ip to my primarym and set the next hop verify-availability to the second link

and configuremy network interface for PBR

Regards

New Member

Re: Static default route with BGP recevied default route

Anyone can help please ?

Cisco Employee

Re: Static default route with BGP recevied default route

Hi Nidal,

Use object tracking with your PBR.

http://www.cisco.com/en/US/tech/tk364/technologies_configuration_example09186a0080211f5c.shtml

HTH,
Lei Tian
Sent from Cisco Technical Support iPhone App

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