Quagga Routing - OSPF and BGP

For the last month or two, I have been "learning by doing" routing, using Quagga.

Quagga uses an abstraction layer called Zebra that sits (architecturally not literally) on top of the various routing protocols that it supports (OSPF, BGP, RIP, et al).

I designed two geographically-separated cluster of OSPF routers - area 0.0.0.1 - and then joined them with a "backbone" of two OSPF routers in area 0.0.0.0. I hosted these on virtual machines running on a KVM host.

From there, I modified the architecture to use BGP to another colleague's KVM virtual machine host that ran BGP.

Some things we learned from this exercise:
1. We learned how to configure the routers using vtysh,
2. We had to make firewall accomodations for OSPF (which uses multicast) and BGP.

We also used an in-house code project that tunnels Quagga. I have not examined the source for this, but that worked also, and required us to make specific firewall changes to allow tunx interfaces.