Summary

This chapter discussed the design of both network addressing and naming. We began by covering route summarization, an important technique that allows you to keep route tables from growing out of control. VLSM allows for discontiguous subnets when using classless routing protocols.

We then discussed private addressing and NAT and how they can be used to stretch out registered addresses. NAT helps conserve IP version 4 addresses and minimizes the cost of public IP purchases. NAT also adds an element of security by hiding real addresses, but that can be a limitation to some applications.

We looked at server and router addressing and discussed some scenarios where planned addresses for these devices can simplify both default router configuration and access list protection.

We looked at DHCP, along with some IPX issues in addressing. DHCP allows for centralized management of IP addresses and can be used across routers by configuring IP helper addresses. IPX addresses are 80 bits in length and include the 48-bit MAC address and up to a 32-bit network address.

Finally, this chapter offered a few suggestions for network naming and looked at the Cisco CNS Network Registrar’s ability to dynamically map network names to IP addresses. Descriptive device names are more useful for a network design and troubleshooting.