This is an exceptionally old document, referencing the 2013 launch expectation, but it contains a bunch of interesting information on the platform database and the communications segment. [1]
Apparently, they have to have accurate ranging to receive from JWST. The interesting portion:
"Ranging is required for JWST, using alternate ground stations in the southern and northern hemisphere. For LEO and L2 missions the accuracy of the ranging is dependent on the tracking of the spacecraft across the sky. For the JWSTs L2 orbit, 21 days of tracking equals about 15 minutes of tracking for a LEO spacecraft."
Apparently, they have to have accurate ranging to receive from JWST. The interesting portion:
"Ranging is required for JWST, using alternate ground stations in the southern and northern hemisphere. For LEO and L2 missions the accuracy of the ranging is dependent on the tracking of the spacecraft across the sky. For the JWSTs L2 orbit, 21 days of tracking equals about 15 minutes of tracking for a LEO spacecraft."
https://ntrs.nasa.gov/api/citations/20080030196/downloads/20...