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245U-E Wireless Ethernet Modem User Manual
67
Rev Version 2.24
Figure 62 Gateway Address
3.18 Routing
When a 245U-E receives an IP frame that is destined for an IP address on a different network, it checks if
the network address matches the network address of one of its own interfaces (hard-wired Ethernet, or
wireless Ethernet, or WDS) and forwards the frame appropriately. However, if the IP network address does
not match the network address of any of its interfaces, the 245U-E will forward the frame to its default
gateway. In this case it is assumed that the default gateway has a valid route to the destination.
In some cases, it is not practical to have just one default gateway. For example, this is true for routed
wireless networks with more than two 245U-E routers, and in some cases when WDS router interfaces
are used. If more than one next-hop router is required, the 245U-E allows for up to 30 routing rules to be
configured. A routing rule specifies a destination network (or host) IP address and the corresponding next-
hop router to which messages for the specified destination will be forwarded. It is assumed that the next-
hop router (or gateway) will then deliver the data to the required destination (or forward it on to another
router that will).
Figure 63
Routing
Figure 63 illustrates a situation where routing rules may need to be configured. In this example, the
245U-E clients need only specify the access point as their default gateway (they require no routing rules
to be configured). However, for the access point to be able to deliver traffic to LAN B and LAN C it needs
to have routing rules configured that specify the respective 245U-E client and routers as next-hop routers
(gateways) to networks B and C. Note that devices on LAN A should specify the 245U-E access point as
their default gateway. An alternative to adding routing rules to the 245U-E in this example would be for
