Nt2640 Project Paper

NT2640

Project Paper

1. Routing tables and how the router will perform a route lookup:

a. Routing Table Format- A routing table is used by TCP/IP network routers to calculate the destinations of messages it is responsible for forwarding. The table is a small in-memory database managed by the router's built-in hardware and software. Each IP address identifies a remote router (or other network gateway) that the local router is configured to recognize. For each IP address, the routing table additionally stores a network mask and other data that specifies the destination IP address ranges that remote device will accept. Home network routers utilize a very small routing table because they simply forward all outbound traffic to the Internet Service Provider (ISP) gateway which takes care of all other routing steps. Home router tables typically contain ten or fewer entries. By comparison, the largest routers at the core of the Internet backbone must maintain the full Internet routing table that exceeds 100,000 entries and growing as the Internet expands.

b. Routing Lookup Mechanism-

c. Classful vs. Classless Routing- Classful Routing, which is sometimes called a classful network. If you are using a classful routing protocol then all of your networks are in different classes and are separated by a router. Remember that the useable IPv4 address ranges are divided into classes. Class A 1-126, Class B 128-191, and Class C 192-223. So when we talk about a classful routing protocol, it will only look at the IP address class and not the subnet mask. This is the problem; if you are using a classful routing protocol you cannot change the subnet mask in any of these networks. You have to use the default subnet mask, so an example is if you have a 172.16.X.X network the default subnet mask is a /16 or 255.255.0.0. So in short you can’t have different size networks when using the same IP address class and a classful routing protocol. Remember

that classful routing does...