Hello, Gerard.
The voice media streams of an MDU can be forwarded in the following two processes:
The process the same as the process of forwarding IP packets: Locate the routing table. For a direct route, request the MAC address corresponding to the peer IP address and then forward voice media streams using Layer 2 switching (requiring ARP proxy supported by the OLT or gateway). For an indirect route, request the MAC address corresponding to the next-hop IP address using ARP and then forward voice media streams using Layer 3 routing.
The process of external forwarding: Query the media gateway in the VoIP configurations, request the MAC address corresponding to the IP address of the media gateway using ARP, and then use this MAC address as the destination MAC address for forwarding media streams. Then, transmit voice media streams to the media gateway regardless of the type (direct or indirect) of a route and then forward voice media streams using Layer 3 routing.
Currently, only the MA5635 uses the external forwarding process by default and the other MDUs use the process the same as the process of forwarding IP packets.
Thanks.