Simulating a Cisco Network

Testing remote connectivity options is usually more challenging than testing the local area network. Remote connectivity frequently involves the use of transmission devices that are not owned or managed by the client. These devices are generally not available to the network administrator for testing purposes. Consequently, the network tester must find ways to test the proposed network plan without having access to the actual transmission devices. The designer can use the following techniques to test remote connectivity designs: 1.simulation, 2. software, 3. Prototype testing using simulated links, 4. Pilot testing in the actual environment. Simulated environments can offer a way to test device configuration and operation. After the design is tested in the simulated environment, remote connectivity can be additionally tested in a trial installation. Network Simulation Software Computer applications offer the designer many tools for testing configurations before implementing them on actual devices. The benefits of using this approach are: 1. Lower cost: Prototype nets are expensive to create and maintain. Networking device configuration options change often. Therefore, maintaining a test environment up-to-date can be challenging, 2. Flexibility: Simulation applications can support several different kinds of devices and connectivity options. Changing configurations and topologies is generally much quicker and easier in a simulation environment, 3. Scalability: Creating a large or complex net in a lab environment is inefficient, 4. Control: The simulation software allows the network administrator to control the entire net operation better. Also the network architect can control the types of traffic to send across the net and the rate at which the traffic is sent. The architect can also stop the simulation to capture and inspect TCP/IP packets at several points in the network. Unfortunately, simulation software programs have a few disadvantages: 1. Limited functionality: simulation software programs can quickly become out-of-date. Moreover, the software may not support all the capabilities of the actual equipment, 2. Unrealistic performance: It is not easy for the software programmers to simulate all of the conditions that can happen in a real network. Consequently, relying on performance observations obtained from simulation software is not accurate. Despite the above disadvantages, using simulation computer applications to test the networks is an excellent way to uncover design errors. Along with network simulation software, other techniques are available to check remote connectivity in a test environment. Practically all WAN devices need an intermediary device to convert the WAN signals to either serial or Ethernet signals at the client premise. These devices include numerous categories of modems and CSU/DSUs. An exception to this rule is Ethernet, which does not require an intermediary device. Simulating a DSL or Cable Connection To simulate a DSL or cable wide area network connection, an Ethernet link can be used. The routers can be connected with an Ethernet crossover cable. Routing protocol metrics can be configured to simulate the metrics of a lower-speed connection by using the bandwidth command on the interface. Static route options can be manually configured by modifying the administrative distance assigned to the network path. This is something that you can easily do on all the Cisco routers.

Manolis Skoras is a Cisco, Microsoft and HP Certified Trainer and systems-network engineer. Recently he created a site about Cisco Certifications to help his students and people around the world to better understand the material they will be tested on, thus having greater success rates. Check Certify4Sure today!