- You configure SCCM clients to for this new feature using client settings, select option called "Enable Configuration Manager client in full OS to share content"
- SCCM client will configure necessary Windows Firewall ports on client, but if there are any network firewalls, ports must be opened also there.
- If SCCM client with Peer Cache enabled will have a package it will tell to management point that it has the package.
- If another SCCM client will ask for content then management point will return all distribution points and Peer Cache enabled SCCM clients for it (if they are in clients current boundary group).
- Peer Cache is fully SCCM technology and does not rely on Windows Branch Cache feature.
Keep in mind that although this is a nice feature, you must not enable it for all clients and your boundary groups must be configured correctly for this to work as expected.
Microsoft documentation here