Ok, my company has three telco providers, each telco provides data links from the central site to different remote sites. Telco provider 'A' provides layer 2 "dedicated" fiber optic links from the central site to remote sites 1, 2, and 3, and each remote site can be accessed through a distinct port on a layer 2 switch at the central site. My company is then free to place layer 3 devices with IPs from a given subnet at the remote sites and central site. That is the ideal scenario.
Now, telco provider 'B' for remote sites 4, 5, and 6, only has satellite links and they say that their transmission network is layer 3, but they have added extra equipment to convert it to layer 2 as required by my company. The only thing is that they can only give us one physical layer 2 port at the central site through which we can access sites 4-6. Layer 3 devices are again connected to the given layer 2 ports at local and remote ends.
Finally, telco provider 'C' for remote sites 7-9, also only has satellite links and has a layer 3 transmission network, but they are not able to give us access to the remote site through a layer 2 device, instead they can only deliver us layer 3 access to the remote sites.This means that the remote end devices must have IPs from their subnet, and we must create routes to their network from our central site.
(all three scenarios are exemplified in rudimentary attached image)
I am trying to work with providers B and C, so that they can migrate to the same scenario as provider A. Unfortunately, I do not know how provider A is able to deliver this scenario, nor do I know if there is some limitation for satellite networks that makes this more difficult.
In conclusion, my questions are: How can a telecommunications carrier convert his layer 3 transmission network to layer 2 at client site ? Once this is done, how can he deliver a link to each remote site on a different switchport?