PHYSICAL ADDRESSING IN A WAN:

 The physical addressing in a WAN is same as in LAN in the following way:

• The data is send in packets equivalent to frames.
• Every packet has a format with header.
• The packet header adds source addresses and destination.
• One part of address checks destination switch. Other part of address checks port on switch. This is given in the figure below.

Figure 

NEXT HOP FORWARDING:

 Packet switch must select outgoing connection for forwarding the packet. There are two types.

• If the destination is local machine, packet switch sends computer port.
• If the destination is added another switch, this packet switch forwards to next hop through connection to next switch.
• The selection of another switch is based on destination address in frame.