Network Map - Part 1

How does my computer connect to the Internet through the network?

When you open a Web browser or check your email on your computer, your computer sends an electronic request out to the Internet to be processed and returned with the information you requested. For this request to arrive at the Internet, it goes through dozens of steps.

The Network Jack

First, your computer splits the electronic information into small, easily transferable packets and labels them with a destination address. The destination address has different parts, just as a letter has a street address, city, state, and zip code. The packets are sent from your computer through an Ethernet cable, which is plugged into a network jack in the wall.

If you are using wireless networking, the packets are transmitted through the air and received by a wireless access point. From here, the access point transmits your packets through an Ethernet cable like your computer does if you're wired.

Communications Equipment Room

From the jack, network cables in the walls connect to a nearby Communications Equipment Room (CER). A CER is a centralized space containing network cabling and equipment.

In the CER, your information travels from the network cable to a switch. A switch is a device that reads a part of the destination address on your packets to decide where they should be sent next. In this case, the packets go through the network cabling to a router, which is one step closer to the final destination.

Routers are similar to switches, but they read a different part of the destination address to guide packets, or traffic, to the next step. The routers are physically located in the campus nodes. A node is a much larger version of a CER and is part of the system that makes up the network core, or the central network for the campus.

The Network Core

The UIUC network core, represented by a cube, is composed of two independent layers with four routers each. The eight main routers are all connected so that if any one router fails or breaks, the others can redirect network traffic through another router or node. This is called redundancy. Redundancy is important because it ensures that even if there is a problem, the information from your computer will still reach its destination without slowing down. The network was designed to be completely redundant, but some buildings haven’t yet connected to more than one core router, so they don’t have the same redundancy.

The routers in the node read the information in the packets, and if those packets are going off-campus, the routers direct the traffic toward the exit architecture.

To the Exit Architecture