Web Caching and Replication

8.1. Overview of Internet Connectivity Architectures

Before discussing alternatives for proxy deployment, we need to understand at a high level how an enterprise obtains its Internet connectivity. Consider Figure 8.1, which depicts at a high level a typical ISP architecture. A large ISP has a backbone network consisting of backbone nodes. Each node has some access routers (ARs) that are the backbone entry points for enterprise customers of the ISP (such as other ISPs) and backbone routers (BRs) that provide connectivity between backbone nodes. Access routers are connected to their local backbone routers via LANs. Backbone routers in different nodes are connected via wide area network (WAN) lines, creating the backbone topology. In addition, some ...