Netopia R5300 - Manual (Page 250)

B-12 User’s Reference Guide
Routers B and C (which could also be Netopia R5000 Series Routers) ser ve the two remote networks that are
subnets of a.b.c.0. The subnetting is accomplished by configuring the Netopia R5000 Series Router with
connection profiles for Routers B and C (see the following table).
The Netopia R5000 Series Router’s connection profiles for Routers B and C create entries in its IP routing
table. One entr y points to the subnet a.b.c.128, while a second entr y points to the subnet a.b.c.248. The IP
routing table might look similar to the following:
Let’s see how a packet from the Internet gets routed to the host with IP address a.b.c.249, which is ser ved by
Router C. The packet first arrives at Router A, which delivers it to its local network (a.b.c.0). The packet is then
received by the Netopia R5000 Series Router, which examines its destination IP address.
The Netopia R5000 Series Router compares the packet’s destination IP address with the routes in its IP routing
table. It begins with the route at the bottom of the list and works up until there’s a match or the route to the
default gateway is reached.
When a.b.c.249 is masked by the first route’s subnet mask, it yields a.b.c.248, which matches the network
address in the route. The Netopia R5000 Series Router uses the connection profile associated with the route to
connect to Router C, and then for wards the packet. Router C delivers the packet to the host on its local
network.
Connection profile Remote IP address Remote IP mask
Bits available for host
address
For Router B a.b.c.128 255.255.255.192 7
For Router C a.b.c.248 255.255.255.248 3
IP Routing Table
Network Address-Subnet Mask-----via Router------Port--Age--------Type------
----------------------------------SCROLL UP--------------------------------
0.0.0.0 0.0.0.0 a.b.c.1 WAN 3719 Management
127.0.0.1 255.255.255.255 127.0.0.1 lp1 6423 Local
a.b.c.128 255.255.255.192 a.b.c.128 WAN 5157 Local
a.b.c.248 255.255.255.248 a.b.c.248 WAN 6205 Local
---------------------------------SCROLL DOWN-------------------------------
UPDATE