Posts Tagged ‘traffic engineering’


Hi Everyone!

The Challenge
People tend to underestimate the important of IGP routing features in modern network. So here is a small challenge scenario for you to practice OSPF traffic engineering. Take a look at the diagram below for information on the topology and link bandwidth. You may assume that every router has a loopback interface for network testing and OSPF router-id selection.


There is a large cloud of media servers behind R4, and the users behind R1 need to use full 300Mbps of bandwidth when downloading files off the servers. The network is running single-area OSPF for IP routing. Ensure you can accomplish the above goal without using MPLS Traffic Engineering or Policy Based Routing. You are allowed to create additional logical interfaces, but the routing protocol, OSPF areas, physical links and their characteristics should remain unchanged. Keep the amount of changes to minimum and do not introduce new IP addresses.

The first person to provide a working solution will receive 100 rack rental tokens from our partner company GradedLabs. Please use your valid e-mail address when posting a comment, so we can locate your INE account.

OK I forgot to rule out the “route-via” option :) Try solving the task without relying on any “policy-based” routing decisions.

The winner is: Antonie Henning ( Ivan Pepelnjak helped finding a logical “loophole” in my scenario by pointing to the “route-via” option available with GRE tunnels and correctly stating there should be 6 end-to-end tunnels to implement proper load-balancing. Hans Verkerk was close in his idea, but used static routing which was slightly against the rules and not as elegant as Antonie’s solution. Chris Stos-Gale and Nitzan Tzelniker came with the correct solution as well, but Antonie completed the challenge ahead of them. Thanks to everyone for participating in the challenge, it’s been fun!

The Solution:
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