As a senior network designer for an IP communications provider, you are asked

to outline a complete end$-$to$-$end infrastructural design for a potential Irish client

company that wishes to implement an integrated all$-$IP based conferencing

$($voice$/$video$)$ and data communication system. The company will have two large

facilities, in Dublin and Galway, each with their own LAN. Your design should

address the following challenges:

a$.$ How VoIP phones chosen can maximise voice quality.

b$.$ How QoS will be achieved across company LANs.

c$.$ How QoS will be achieved across intermediate WAN. You can assume that

your company uses DiffServ in its IP network

$(25$marks$)$