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Routing Fundamentals for Cisco CCNA
Configuring Default and Static Routes

Routing Fundamentals for Cisco CCNA

Given below are some examples of Link State routing protocols:

3.1. Open Shortest Path First (OSPF): Developed for IP networks, it uses the shortest path first (SPF) algorithm to calculate the best path to a destination. It supports VLSMs and CIDR, and uses a link state database to store information about the network topology.

3.2. Intermediate System to Intermediate System (IS-IS): Developed for both IP and ISO networks, it uses the SPF algorithm to calculate the best path to a destination. It supports VLSMs and CIDR, and uses a link state database to store information about the network topology.

3.3. Integrated IS-IS: It is an extension of IS-IS that allows it to carry IP routing information.

3.4. Optimized Link State Routing (OLSR): Developed for mobile ad-hoc networks, it uses a multi-point relaying (MPR) mechanism to reduce the flooding of link state information. It is designed to work efficiently in wireless networks with high mobility.

3.5. Link State Routing Protocol version 2 (LSRPv2): It is a new version of LSRP that is designed to work with IPv6 networks.

Many of the above protocols are widely used in modern networks, particularly in enterprise environments, and are known for their scalability, stability, and fast convergence.

4. Path-Vector Routing: Path-vector routing protocols, such as Border Gateway Protocol (BGP), use the AS-Path attribute to determine the best path to a destination. These protocols exchange information with their neighboring routers and update their routing tables accordingly.

5. Hybrid Routing: Hybrid routing protocols, such as Enhanced Interior Gateway Routing Protocol (EIGRP), combines aspects of distance-vector and link-state routing protocols.

2. Configuring Default and Static Routes

2.1 Configure default route on a cisco router:

Overview of how to configure a default route (also known as a gateway of last resort) on a Cisco router:

1. Enter global configuration mode by using the "configure terminal" command.
2. Configure a default route by using the "ip route 0.0.0.0 0.0.0.0 [next-hop IP address]" command. For example, "ip route 0.0.0.0 0.0.0.0 192.168.1.1" will configure a default route with the next hop IP address of 192.168.1.1.
3. Optionally, you can configure a description for the default route by using the "description [description text]" command.
4. Optionally, you can configure an administrative distance for the default route by using the "distance [administrative distance]" command.
5. Verify the default route configuration and status using the "show ip route" command.
6. Monitor and troubleshoot the default route by using the "debug ip static" command.

Please note that the above steps are a general overview of how to configure default route on a Cisco router, the specific command syntax and configure may vary depending on the IOS version and the specific requirements of your network.

2.2 Configuring static route on a Cisco router:

1. Enter global configuration mode by using the "configure terminal" command.
2. Configure a static route by using the "ip route [destination network] [mask] [next-hop IP address]" command. For example, "ip route 10.0.0.0 255.0.0.0 192.168.1.1" will configure a static route for the 10.0.0.0/8 network with the next hop IP address of 192.168.1.1.
3. Optionally, you can configure a description for the static route by using the "description [description text]" command.
4. Optionally, you can configure an administrative distance for the static route by using the "distance [administrative distance]" command.
5. Verify the static route configuration and status using the "show ip route" command.
6. Monitor and troubleshoot the static route by using the "debug ip static" command.

Please note that the above steps are a general overview of how to configure static routes on a Cisco router, the specific command syntax may vary depending on the IOS version and the specific requirements of your network.