Hello Rachelle,

first of all the same node can have P role for some destination prefixes and it can have PE role for other destination prefixes.

A fault tolerant design 1 level (device or link fault) requires two PE nodes per site and two inter site links.

So we could count:

2 PE nodes for SG1

2 PE nodes for SG2

2 PE nodes for SG3

2 PE nodes for Myanmar

2 PE nodes for Bangladesh

links should be deployed among all main sites for optimal forwarding or SG2 site can be thought with two P nodes for communication between sites.

About link speed:

the choice depends on what applications are needed and on the possible technologies in your geographic area.

For connecting sites you could think to use DS3 or E3 links as a good choice.

Using multiple E1 links is also possible but this may lead to a need for BW upgrade on the mid term.

The number of users in each site plays a role too.

Applications play a role too: if one of the usage of this network is communication between data center you need to consider this.

Voice BW usage can be calculated with great accuracy by knowing the codec used and how many contemporary calls you want to permit between sites/locations.

Hope to help

Giuseppe