Optical Multi-Domain Routing
Source: Optical Society of America
The Internet is a decentralized set of networks known as domains or Autonomous Systems (ASs), each one managed by a single authority and under a common routing policy. Today's Internet is built by the interconnection of more than 29.000 ASs on a well-known network hierarchy. This hierarchical structure is rooted in the two different relationships that could exist between transit ASs, namely, peer-to-peer or customer-provider, hence motivating the definition of different transit ISPs according to their established relationship (Tier-1, Tier-2 or Tier-3). The problem of selecting routes to forward traffic on an end-to-end scenario is known as multi-domain (or interdomain) routing. Traditionally, multi-domain routing has been a well-known problem largely analyzed in pure IP (packet) networks.