Question

Case 1: A local hospital asks you to help improve its network’s fault tolerance. The hospital’s network carries critical patient care data in real time from both a mainframe host and several servers to workstations in operating rooms, doctors’ offices, the billing office, teaching labs, and remote clinics across the region. Of course, all of the data transferred is highly confidential and must not be lost or accessed by unauthorized personnel. Specifically, the network is configured as follows:

● Six hundred workstations are connected to five shared servers that run Solaris. Fifty of these workstations serve as training computers in medical school classrooms. Two hundred workstations are located in doctors’ offices and are used to view and update patient records, submit accounting information, and so on. Twenty workstations are used in operating rooms to perform imaging and for accessing data in real time. The remaining workstations are used by administrative staff.

● The clients are connected in a fully switched, star-wired bus network using Ethernet 1000Base-T technology.

● An Internet gateway supports e-mail, online medical searches, and VPN communications with four remote clinics. The Internet connection is a T3 link to a local ISP.

● A firewall prevents unauthorized access from the T3 connection into the hospital’s network. The hospital’s IT director asked you to identify the critical points of failure in her network and to suggest how she might eliminate them.

On a sheet of paper, draw a logical diagram of the network and identify the single points of failure, and then recommend which points of failure should be addressed to increase availability and how to achieve this goal.

(I want simple and straight forward answer as well as the diagram)

Answer 1

1. From the information network has number of single points of failure.
2. The Star topology in my opinion would be the largest, followed by the single T3, and an Internet Gateway that seems to support email, VPN connections, and online medical searches in an effective away.
3. Although a single firewall is not usually recommended you can make sure that if the firewall dies on you that no traffic comes into the business. On the other hand, no traffic will be able to leave, either.

Problem with star topology:

1. The star topology means that if near the center of the topology   one link in the star goes down that all the links downstream would be dead.
2. But in this A star topology would work. because ,Ideally you would want dual T3's, with access to the internet from different providers. If one goes down, or if one provider has large problems the other link will be available.

The recommendations for those points of failure and addressed to increase availability:

1. There would ideally be two T3's from different providers bundled together for ease of use by a router using EtherChannel or a similar protocol.
2. Should one of them experience trouble there would be no human intervention to keep the connection up.

About firewall:

• The internet gateway would need to be duplicated. email, VPN, and online medical searches if all three are housed on the gateway it would be best to duplicate these on the second gateway.
• The firewall would be best to duplicate also.
• We could use a DNS round robin. For sharing the load between the internet gateways and firewalls, or many other High Availability protocols.
• VRRP is the first HA protocol that comes to mind.