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BGP Incoming traffic load balancing

Siddique
Beginner
Beginner

2 Router connected with 2 ISP and EBGP configured. Now i want to load balance incoming traffic. Via ISP 1 70% traffic and via ISP 2 30% traffic. For more understand please check my attached screenshot. 

3 Accepted Solutions

Accepted Solutions

we can not full control Inbound traffic, but for your case 
split the subnet in Enterprise you advertise to both ISP 
subnet /24 will split into
1/26  2/26  3/26  4/26


advertise for ISP1 1/26
advertise for ISP2 2/26 3/26 4/26

this not give you exactly 30/70 but at least give you some load balance. 

View solution in original post

As I said, I can believe is possible influence incoming traffic in 70/30%. What you can do is choose one ISP from where you want to receive the traffic.

Once you device which ISP will be, you can apply a route map on this neighbor

neighbor  x.x.x.x route-map outbound out

 

route-map OUTBOUND permit 10

 match ip address prefix-list  XX

 set as-path prepend  "AS" "AS" "AS"

 

ip prefix-list XX permit 0.0.0.0/0

 

This is for incomming  traffic.

 

For outgoing traffic you can do a lot of things because that´s is under you control.

 

I will leave here this link.

 

https://techmusa.com/bgp-attributes-path-selection/ 

View solution in original post

There is a solution that could achieve very close to a 70/30 split of incoming traffic. But I doubt it would be feasible for the original poster. This solution requires that you have a quite large block of Public IP, for a 70/30 split a block of /22 would be ideal.

As an example think of a network that has been assigned this /22 block: 200.200.200.0/22 (which includes the networks 200.200.200.0, 200.200.201.0, 200.200.202.0, and 200.200.203.0). This network is connected to ISPA and ISPB. The network configures BGP for ISPA to advertise 200.200.200.0/24, and configures BGP to ISPB to advertise 200.200.201.0, 200.200.202.0, 200.200.203.0. This produces a 25/75 split of inbound traffic. And to provide failover in case of a problem with one of the ISP the network configures BGP to advertise 200.200.200.0/22 to both ISP. In normal operation the more specific advertisement will be used. But if there is a problem with one link then its specific advertisements are withdrawn and those networks will use the other ISP.

HTH

Rick

View solution in original post

8 Replies 8

Hi

  For inbound traffic what you can do is use AS-PREPEND and influence from which ISP you are going to receive the traffic, but I dont believe you can interfere at this level.  You can have the same control as you have in the outbound.

Thanks for your reply. But still I am not clear. My query is how can i do load balancing for all incoming traffic between 2 ISP which are connected with my 2 local router. My topology like Single Multihomed.

Exactly what I said. You have ISP A and ISP B and you want to influence how traffic comes to you router, right?

You can use AS-PREPEND and makes the path through one ISP looks worst then the path through the other ISP.

However, this is all traffic or no traffic, you can split it in 70/30 %.

single-multihomed-connection-two-isps.png

Many Many thanks for your reply. First of all I would like to highly request you to  share the configuration example for 70% and 30%.

2nd thing my topology is  single-multihomed-connection-two-isps-redundancy.png  like this . So how can I utilize this 2 link simultaneously and can do load balancing. Thanks Again sir.

As I said, I can believe is possible influence incoming traffic in 70/30%. What you can do is choose one ISP from where you want to receive the traffic.

Once you device which ISP will be, you can apply a route map on this neighbor

neighbor  x.x.x.x route-map outbound out

 

route-map OUTBOUND permit 10

 match ip address prefix-list  XX

 set as-path prepend  "AS" "AS" "AS"

 

ip prefix-list XX permit 0.0.0.0/0

 

This is for incomming  traffic.

 

For outgoing traffic you can do a lot of things because that´s is under you control.

 

I will leave here this link.

 

https://techmusa.com/bgp-attributes-path-selection/ 

There is a solution that could achieve very close to a 70/30 split of incoming traffic. But I doubt it would be feasible for the original poster. This solution requires that you have a quite large block of Public IP, for a 70/30 split a block of /22 would be ideal.

As an example think of a network that has been assigned this /22 block: 200.200.200.0/22 (which includes the networks 200.200.200.0, 200.200.201.0, 200.200.202.0, and 200.200.203.0). This network is connected to ISPA and ISPB. The network configures BGP for ISPA to advertise 200.200.200.0/24, and configures BGP to ISPB to advertise 200.200.201.0, 200.200.202.0, 200.200.203.0. This produces a 25/75 split of inbound traffic. And to provide failover in case of a problem with one of the ISP the network configures BGP to advertise 200.200.200.0/22 to both ISP. In normal operation the more specific advertisement will be used. But if there is a problem with one link then its specific advertisements are withdrawn and those networks will use the other ISP.

HTH

Rick

we can not full control Inbound traffic, but for your case 
split the subnet in Enterprise you advertise to both ISP 
subnet /24 will split into
1/26  2/26  3/26  4/26


advertise for ISP1 1/26
advertise for ISP2 2/26 3/26 4/26

this not give you exactly 30/70 but at least give you some load balance. 

MHM suggests an interesting solution. The flaw in this suggestion is that most ISP will not accept any advertisement smaller than /24. So advertising /26 is not likely to work.

HTH

Rick
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