User's Manual Part 1

34 APCD-LM043-8.0 (DRAFT C)
3: Detailed Description
Figure 21 Addressing of Packets—Switched Ethernet Mode
As shown in Figure 21, if NAT is not enabled in the NAP Router, then the source and
destination IP addresses are maintained throughout the route between the end-user PC and
network servers. The source and destination MAC addresses, however, change whenever the
packet is passed through a router. This change of MAC addresses also takes place in the
CCU router application.
Network Server
NAP Router
(no NAT)
EUM CCU BackhaulSwitch
End-user PC
Internet Router
(sev eral)
Network Server IP Address
End-user PC IP Address
End-user PC MAC Address
Destination IP
Address
Source IP
Address
Destination
MAC Address
Source MAC
Address
AABB
Destination IP
Address
Source IP
Address
Destination
MAC Address
Source MAC
Address
Destination IP
Address
Source IP
Address
Destination MAC
Address
Source MAC
Address
Destination IP
Address
Source IP
Address
Destination
MAC Address
Source MAC
Address
NAP Router MAC
A
Address
Internet
Router MAC
A
Address
Network
Server MAC
Address
NAP Router
MAC
B
Address
Internet
Router MAC
B
Address
End-user PC IP Address
Network Server IP Address
End-user PC MAC Address
NAP Router MAC
A
Address
NAP Router
MAC
B
Address
Internet
Router MAC
B
Address
Internet
Router MAC
A
Address
Network
Server MAC
Address
End-user PC to Network Server
Network Server to End-user PC
Backhaul