Nokia MW1122 - Manual (Page 19)

MW1122 Administrator Manual
E Copyright Nokia Networks Oy C33902001SE_00 2-8
possible to route ETH-LLC encapsulated packets and at the same time
bridge, for example, PPPoE packets (PPPoE packets are transported
directly over Ethernet frame, not within IP packets).
2.2.2 Routing
Routing is based on routing entries in a routing table. Static routes are
added via the management interface and dynamic routing is done using
RIP and RIPv2. Routing is done between the Ethernet 10Base-T
interface, the wireless LAN interface and the virtual channel
connection (VCC) of the ATM/ADSL interface. MW1122 supports up
to 8 simultaneous VCCs.
MW1122 supports IGMP (Internet Group Management Protocol)
proxy receive function for IP multicast applications.
2.2.3 Bridging
Bridging is supported to provide full protocol transparency. Bridging
can be used simultaneously with IP routing. MW1122 works as a
self-learning bridge supporting up to 1024 MAC addresses. Bridging
is done between the Ethernet 10Base-T interface, the wireless LAN
interface and each ATM VCC interface. Optionally, the bridging
between the VCCs can be disabled.
2.2.4 Network Address Port Translation
MW1122 supports Network Address Port Translation (NAPT) for
TCP/IP, UDP/IP and ICMP/IP protocols. When NAPT is used, a single
IP address is allocated to a VCC which leads to the public IP network.
The Ethernet subnet has private IP addressing and is not visible to the
VCC. NAPT translates the IP source address and source port number
dynamically to the VCC IP address and port number. Similarly,
packets coming from the VCC are mapped back to the original
destination addresses. NAPT allows up to hundreds of hosts to share a
single VCC IP address to the public network. The principle of Network
Address Port Translation is presented in Figure 2-4.