Marlon,
Both MSR and AP-175 can be used for P2P or P2MP long distance links. The main difference between MSR and AP-175 are:
1. AP-175 runs AOS and requires Aruba controller to work; while MSR runs Aruba MeshOS and can work without controller.
2. AP-175 has all AOS features but only one radio can work in the 5Ghz with another radio on 2.4Ghz. MSR doesn't have advanced AOS features such as ARM and Firewall, but MSR allows you to configure any radio in any available frequency band (2.4Ghz, 4.9Ghz and 5Ghz) in any combination.
For long distance links, both ends of the link has to be the same type, which means both have to be either MSR or AP-175. You cannot use MSR or AP-175 on one side while a laptop with high gain antenna on the other side.
To achieve the 13km distance, as Mohammed suggests, the best solution will be to use a two-hop solution, as following:
MSR1(Radio1)------(7km)-------(Radio 1)MSR2(Radio 2)------(7km)------(Radio 1)MSR3
In this case, yes, we recommend using ANT-2x2-5614U 14dBi high gain MIMO antenna to achieve good throughput.
Best,
Xu