Chapter 2. What is a Cisco network?

 

Every organization’s most valuable traffic passes through two types of networking devices: routers and switches. Cisco makes some of the most popular, dependable routers and switches around, so most organizations standardize on Cisco for these devices. For other networking devices like firewalls and wireless access points, they may go with Cisco or they may choose a different brand altogether. But as long as the network uses Cisco routers and switches, you can consider it a Cisco network.

There’s no requirement that you must use Cisco-branded routers and switches. You can use a Cisco switch with a Juniper router, and they’ll work together just fine. You can use a Cisco router with a Juniper switch, and that will work fine too. But there are a couple of disadvantages to doing this.

First, the steps to configure a Cisco device are substantially different from the steps to configure a Juniper device. The commands, terminology, and order in which you do things are different. Administering a mixed network requires knowing how to configure both platforms and getting them to interoperate. This book addresses only the Cisco side of things.

Second, if you have a problem on your network and aren’t sure whether it’s the router or switch, you have to open support tickets with both companies. In the worst case, you get a lot of finger-pointing between the companies. In the best case, you get a delayed resolution.

2.1. The truth about routers and switches

2.2. MAC addresses

2.3. The Ethernet frame: a big envelope

2.4. Broadcast domains

2.5. Internet Protocol addresses

2.6. Connecting broadcast domains using a router

2.7. Traversing broadcast domains using a default gateway

2.8. Managing routers and switches

2.9. Hands-on lab

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