In the previous article, we had some general parameters defined, which will be used to design the network around. The first thing we will do is figure out our WAN connectivity.

WAN

After reviewing multiple telecom provider offerings, the determination is made to enter into an agreement with bellX. bellX will provide a private MPLS cloud for the wide area network requirements. Ninety two offices will have T1 access into the bellX MPLS cloud with a 512kb port speed. Memphis, which is the only claims combination office without datacenter space, will have a full 1.5mb port speed. The other two combination office/datacenters will have T3 access, with the full 45mb port speed.

With a decision made on how the offices will be connected together, now we can start working on the overall design. Here are a few points that need to be considered during the design phase.

• Redundant internet connections
• Redundant wide area connectivity between the two datacenters
• Centralized phone system, so there is minimal phone infrastructure to manage in each office
• Redundancy in the Phone Switch & Call Center infrastructure
• Redundant internet DMZ for highly available public web sites

The first thing needed is to sketch out a high level design drawing. Visio can be used to quickly sketch out a high level drawing. It can also be used later to expand a high level drawing into a detailed design drawing.  The following is a high level diagram of the datacenter networking:

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