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BGP Transit Peering Issue

eyep
Beginner
Beginner

We are 2 physically separate Data centres, requirement is to design resilient internet links. 

We have ordered 2 separate internet links with 2 ISPs, both came with their own address ranges, we then registered with RIPE as a result acquired /22 public range.

The objective now is to route all 3 address ranges i-e ISP 1, ISP 2, and our /22 via both ISPs. When I put the request through received following response: We can indeed setup the peering and provide a session over your /22 range, however we cannot assign the prefix list to learn the other networks. Creating the initial peering will allow you test with the single range only. We cannot advertise your ISP 1 range as this belongs to company X and we cannot route this into our network as the range does not belong to us.

Please Advice, as I understand this should be doable ?

 

1 Accepted Solution

Accepted Solutions

Simon Hill
Beginner
Beginner

An ISP will only advertise its own address space (plus any provider independent ranges it caters for) out of its transit and peering links. Each ISP will advertise your provider independent /22 and inbound traffic will flow to your network from both providers, most often based upon shortest AS_PATH. However, this does leave you open to asymmetric routing. Therefore, you might want to split your /22 in half and advertise a /23 to each ISP (along with the /22 in case of a single ISP failure.)

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9 Replies 9

Simon Hill
Beginner
Beginner

An ISP will only advertise its own address space (plus any provider independent ranges it caters for) out of its transit and peering links. Each ISP will advertise your provider independent /22 and inbound traffic will flow to your network from both providers, most often based upon shortest AS_PATH. However, this does leave you open to asymmetric routing. Therefore, you might want to split your /22 in half and advertise a /23 to each ISP (along with the /22 in case of a single ISP failure.)

Does that mean we can't load balance between the 2 ISPs? 

You can load balance in both directions. However, inbound traffic in particular will not be evenly balanced between the two ISP's. There are some technologies that help, but I'm not very familiar with them or what kit is required. Check out Cisco PfR: http://www.cisco.com/c/en/us/products/ios-nx-os-software/performance-routing-pfr/index.html

Thanks for your prompt response Simon.

Does that mean we can't load balance between the 2 ISPs? 

Does that mean we can't load balance between the 2 ISPs? 

Does that mean we can't load balance between the 2 ISPs? 

Does that mean we can't load balance between the 2 ISPs? 

Hi Simon Hill,

 

Could et me have your skype id.

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