Combining two PTP 820S 1+0 radio links together to form a PTP 820S 2+0 link can be a daunting task.
You can choose internal LAG OR combine the links externally with a switch (that supports LAG).
You will manage the units with out-of-band management. (The slides list in-band management, but it's not possible to manage the two radios "inside" or "behind" a LAG.)
You can power the links with external DC OR Power over Ethernet (PoE).
You also need to consider what kind of lightning protection to use, and where to connect the ODUs to each other (if needed).
Below on the left is a PTP 820S 2+0 link with internal LAG, Out-Of-Band management, and external DC power. Notice that the two units are connected via ETH1 with an Ethernet cable, and the data stream comes up the tower on a Fiber cable.
Below on the right is a PTP 820S 2+0 link with external LAG, Out-Of-Band management, and either external DC power or PoE. (Since each unit is connected to an external switch via ETH1, the units can be powered via PoE or external DC. Notice that if external DC powers the units another pair of LPUs must be installed at the top of the tower.)
But wait!
How would you use internal LAG and PoE? (This is remarkable, since only ETH1 supports PoE!)
Below on the left is a PTP 820S 2+0 link with internal LAG, Out-Of-Band management, and PoE. Notice that the two units are connected via ETH2 with a Fiber cable, and the data stream comes up the tower on an Ethernet cable connected to the upper unit.
Notice that the lower unit has a PoE cable, but it's only using that cable for power.
Notice that if you use the PTP 650 PoE injector, you'll need the additional LPU. (If you use the PTP 820 PoE injector, you can take advantage of the built-in surge supression in both the PoE injector and the ODU.)
Notice also that you don't have to connect the units with Fiber; you could use an Ethernet cable. However, remember that ETH2 is SFP, so for Fiber, you need Fiber SFP modules, and for Copper, you need Copper SFP modules.
Below on the right is a PTP 820S 2+0 link with external LAG, Out-Of-Band management, and PoE.
Does internal LAG with PoE REALLY require that the two units be connected via Fiber? Not necessarily. ETH2 and ETH3 are SFP, so you could use Copper SFP modules and connect the units with an Ethernet cable.
Remember that ETH1 must have a separate, different LPU if PoE is not used. (Put LPU on ETH1 if external DC powers the unit.)
Use an LPU for the MGT port.
Lastly, sometimes you may want to run all the cables up to the ODUs, and connect the ODUs (if needed) at the base of the tower.
Remember, with internal LAG and PoE, you DON'T need to connect the units via Fiber, but you will need two SFP modules per link end, since you'll be connecting the units using ETH2.
BOTTOM LINE: With internal LAG, if the unit with the internal LAG fails, the entire link fails. With external LAG, if one link fails, the other can still be used!
I hope this helps!
Dave