Multiple service territory?

[DasheEbra]

I'm in the midst of considering service territories and coordinate systems, and I have a few queries:

Regarding Service Territory Extent:

1. Can a service territory consist of multiple parts (e.g., two or three polygon features)?
2. Is it possible to update the extent of the service territory? For example, if our company expands into a new geographical area that was previously not part of our service territory, can we add this new location 'while the UN up and running'?
3. To avoid potential future issues with the extent, is it feasible to create a polygon that encompasses all possible areas, such as covering all states in the USA?

Concerning Coordinate Systems:

Does ESRI recommend a specific type of coordinates, such as PCS or GCS?

Thanks

[JohnAlsup]

A service territory class can contain multiple polygons.  

Changing the extents of the service territory class after creating the utility network is not supported.

You should make your service territory class extent large enough to cover all your current and future service territory before creating the UN.  

[RobertKrisher]

For item #3 you should always buffer out your service territory with room for expansion, but having an unnecessarily large service territory will impact the default grid sizes for your spatial index (database dependent, but you may need to adjust them after deploying), it will also prevent us from being able to leverage certain performance optimizations during validate network topology.

[RichardKoch]

To assist with visualization of this and the concepts behind it I am going to share some shots from our implementation. By no means am I saying we got this right. Just showing what we did and how you might relate it to your work and work out the best path forward for your organization. 

1. Our UN defined SERVICE TERRITORY (the one Robert and John speak of above that cannot be changed)(second note - this area is the same for all three instances and all three instances are in the same projection.)
2. We have three instances East, West, and South (I will show the footprint of the west instance.)
3. Finally in the last shot are our migrated Poly Boundary layer which contains all the polygons from our old system. they are all in one layer but can be definition queried to get to what you need (Operating company, district, and so forth and then used for spatial analysis.)