Case Study Answers Case Study 3 Medi Bill Services

1 Characterize the traffic between the remote offices and MediBill. Internet traffic, email traffic, and database transfer traffic.

2 What type of router would you recommend for Internet access to MediBill?

An access router such as a 2500 or a 2600 would be ideal because there is a line speed of T1. A 2600 would be necessary over a 2500 if the client needed a CSU/DSU. The 2500 access routers do not support one.

3 If the Internet access router were to be upgraded to support two T1s using Border Gateway Protocol (BGP), what would be the best choice?

For line speeds higher than T1, you would need multiple serial interfaces. However, the key in choosing the router would be the need for the router to have enough processing power to support BGP convergence and route calculations and the additional memory to support the BGP routing tables. Therefore, a Cisco 3640 router would be recommended.

4 What type of router would you recommend for the hospital?

The hospital would also need an access router such as a 2500 or a 2600. The hospital currently has a T1 connection to MediBill but might need a redundant connection. Both routers will adequately serve the needs for the hospital; however, the 2600 is a better choice. The 2600 is a good choice for the T1 because the WAN interface card modules can support an integrated CSU/DSU component for the T1 access. Also, the WAN interface card module for the 2600 could support a backup ISDN or even a second T1, if necessary.

5 What type of WAN topology is the hospital's connection to MediBill?

This is logically a point-to-point connection because there are two end points connected together. It is a point-to-point leased line because the T1 provides a connection between two end points through the carrier's T1.

6 If Mr. Lee wanted to implement Frame Relay connections to the six remote offices with the current bandwidth, what would be the CIR for each office?

The existing offices use a 56-Kbps dial-up service, so the CIR would be 56 Kbps per office. The CIR is the guaranteed throughput rate for each connection.

7 Mr. Lee has determined that MediBill will need a CIR of 1.544 Mbps. If all the remote offices need to communicate with MediBill corporate offices, would Mr. Lee's calculation cause a bottleneck?

No. Mr. Lee's calculation should be based on adding all the CIRs for the remote offices. There are six remote offices, which means that the total of the CIRs is 336 Kbps. That is more than enough for MediBill to support the other offices and their need for greater CIRs to support their new Internet services.

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