Select a classful IP network number that can support the total number of computers, old Obtain new addresses from the new DHCP server on the original 225 computers.

L E S S O N Understanding Wide Area Networks 7 overhead packet switching packet switching exchange PSE permanent virtual circuit PVC POTSPSTN primary rate ISDN PRI Routing Information Protocol RIP Synchronous Optical Network SONET static routing synchronous T1 T3 T-carrier trailer virtual circuit X.25 K E Y T E R M S asynchronous transfer mode ATM basic rate ISDN BRI Border Gateway Protocol BGP broadband cable Committed information rate CIR CSUDSU digital subscriber line DSL dynamic routing fiber distributed data interface FDDI Frame Relay header hops Integrated Services Digital Network ISDN Interior Gateway Routing Protocol IGRP leased lines Open Shortest Path First OSPF O B J E C T I V E D O M A I N M A T R I X S KILLS C ONCEPTS MTA E XAM O BJECTIVE MTA E XAM O BJECTIVE N UMBER Understanding Routing Understand routers. 2.2 Defining Common WAN Understand wide area 1.3 Technologies and Connections networks WANs. 146 Understanding Wide Area Networks | 147 Your client Proseware, Inc., needs to expand its network. Previously, you set up local area networks for Proseware, but now the company wants a wide area network WAN with all the routers necessary to make those connections. You must give Proseware several wide area networking options, along with the different types of routers that will work best for each of those options. The skills required for this task include the ability to document wide area networks and the know-how to install various networking services and protocols. Developing these skills requires a lot of knowledge, so this lesson defines the most com- mon WAN technologies available and increases your understanding of routing protocols and routing devices. ■ Understanding Routing Routing is the process of moving data across networks or internetworks between hosts or between routers themselves. Information is transmitted according to the IP networks and individual IP addresses of the hosts in question. A router is in charge of maintaining tables of information about other routers on the network or internetwork. It also utilizes several different TCPIP protocols to transfer the data and to discover other routers. IP routing is the most common kind of routing, just as TCPIP is the most common protocol suite. IP routing occurs on the network layer of the OSI model. THE BOTTOM LINE CERTIFICATION READY How can you differentiate between static and dynamic routing? 2.2 Identifying Static and Dynamic Routing A static route is one that has been manually configured. A dynamic route is one that has been implemented dynamically with special routing protocols. In this section, we will configure RRAS statically and then add the Routing Information Protocol RIP to allow for dynamic routing. Static routing refers to the manual configuration of a router. For example, when a routing entry is manually entered into the routing table with the route add command, this is known as static routing. We demonstrated a basic example of this in Lesson 5. An example of a static router is a Windows Server 2008 computer with two network adapters and IP routing IP forwarding enabled, as shown in Lesson 6. This is a basic type of router that does not change with the network and is not fault tolerant. Statically entered routes do not “know” what is happening on the network; they cannot sense new routers or the modified state of a particular router. Accordingly, there is a great deal of maintenance required with a static router. Because of this, the better solution is to utilize dynamic routing. Dynamic routing is implemented by dynamically configuring routing tables. This is done with dynamic routing protocols such as RIP and OSPF, as mentioned in Lesson 5. Both of these are part of the TCPIP suite of protocols, and they both work on layer 3 of the OSI model. It is important to be able to distinguish between routable protocols and routing pro- tocols. NetBEUI is an example of a nonroutable protocol. An example of a routable protocol would be TCPIP or RIP. Let’s talk further about RIP and some other routing protocols: • Routing Information Protocol RIP: A dynamic protocol that uses distance-vector routing algorithms to decipher which route to send data packets. In packet-switched net- works, a distance-vector routing protocol uses the Bellman-Ford algorithm to calculate where and how data will be transmitted. The protocol calculates the direction or interface 148 | Lesson 7 that packets should be forwarded to, as well as the distance from the destination. RIPv1 and RIPv2 are common among today’s networks. • Open Shortest Path First OSPF: A link-state protocol that monitors the network for routers that have a change in their link state, meaning they were turned off, turned on, or restarted. This is perhaps the most commonly used interior gateway protocol in large networks. Interior gateway protocols are used to determine connections between autonomous systems. • Interior Gateway Routing Protocol IGRP: A proprietary protocol used in large net- works to overcome the limitations of RIP. • Border Gateway Protocol BGP: A core routing protocol that bases routing decisions on the network path and rules. When it comes to larger networks and the Internet, routing tables can become cumbersome. A router requires a lot of fast, efficient memory to handle these tables. Older routers simply can- not cope with the number of entries, and some protocols such as BGP might not work prop- erly on these routers. Because the Internet is growing so quickly, ISPs collectively utilize CIDR in an attempt to limit the size of routing tables. Network congestion and load balancing are also issues. Depending on the scenario, you might need to use newer routers with more memory and faster network connections, and you should carefully consider which protocols you use. Generally, a small to mid-sized company can make do with RIP. Let’s show this in action. CONFIGURE RRAS AND ADD RIP GET READY. In this exercise, you will configure RRAS as a NAT server and install RIP on a Windows server. We will be using Windows Server 2008 Standard.

1. Go to the server and access the MMC created previously. If you do not have one,

create a new one and add the RRAS snap-in.

2. Expand the Routing and Remote Access snap-in, then right click the server name and

select Configure and Enable Routing and Remote Access. 3. Click Next for the welcome window. 4. Select the Network address translation NAT radio button and click Next. 5. In the NAT Internet Connection screen, leave the default Create a new demand-dial interface to the Internet option selected and click Next. Your options might be slightly different depending on the type and amount of network adapters present on the server.

6. Click Next to apply the selections.

7. Click OK for the Routing and Remote Access pop-up window.

8. Click Next to start RRAS. This will bring up the Demand Dial Interface wizard.

9. Click Next for the welcome screen.

10. Leave the default Interface name and click Next.

11. Leave the default radio button Connect using VPN and continue by clicking Next.

12. In the VPN Type window, leave the current selection and click Next.

13. Enter a destination address of 192.168.1.100 and click Next.

14. Leave the defaults for Protocols and Security and click Next.

15. For the Dial-Out credentials, enter the following:

Username = administrator Leave the rest of the information blank and click Next. 16. Click Finish for the completion window. 17. Click Finish for the RRAS completion window. At this point, you should see your RRAS server modified. It should also have a green arrow pointing upward, signifying that it is running. An example is shown in Figure 7-1. If you get an error message saying “Class not registered 80040154” or “RPC server is not available,” try installing the Role called Network Policy and Access Services, if you haven’t already. TAKE NOTE Understanding Wide Area Networks | 149 If you encounter any problems, consider removing unnecessary services, such as the previ- ously installed DHCP and DNS. Also make sure those roles have been completely removed in the Server Manager. INSTALL RIP GET READY. Now, install RIP by performing these actions: 1. In the Routing and Remote Access snap-in, navigate to: Servername IPv4 General

2. Right click General, then select New Routing Protocol.

3. In the New Routing Protocol window, select RIP version 2 for Internet Protocol and

click OK. This should install RIP into the IPv4 portion of RRAS, as shown in Figure 7-2. 4. Save and close the MMC. Figure 7-1 Configured RRAS server Figure 7-2 RIP installed