Chapter 2
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2 A switching function
- allows the device to accept a
packet from one protocol and
forward it to a second protocol.
When routing, the device accesses routing address tables to determine the best
path for each packet to take. Routing tables can either be seeded as a static path
or built dynamically from broadcast packet information. The ADSL devices
switch the internet protocol (IP) between the 10BaseT/LAN interface and the
ADSL/ATM interface. The device also supports the Routing Information
Protocol, RIP[v1.0] and RIP[v2.0] to collect path routing information.
2.4 Network Address Translation
Network Address Translation (NAT) provides a mechanism for private
networks to access registered networks, such as the Internet, without requiring a
registered subnet address. NAT eliminates the need for host IP numbering and
allows the same IP addresses to be used in multiple Internet.
With NAT, the LAN addresses are private. These addresses are translated to
public IP addresses when IP addresses are forwarded. The NAT translation
function is compatible with standard IP routing.
