2000, 2001 Cirronet
Incorporated
8
M-2410-0007 Rev -
TCP/IP Addresses
Each SEM must be configured with a unique IP address that is appropriate for the
network where the SEM will be used. The default IP address is 0.0.0.0. The IP address
can be set using the
ip
command through the serial-port interface or automatically by a
BOOTP or DHCP server. The
ip
command takes one or two parameters. The first
parameter specifies the IP address for the SEM, and the second optional parameter, if
present, specifies the netmask for the SEM. If the second parameter is not used, the
netmask is set to the default netmask for the IP address specified. For example, the
command:
ip 192.168.0.1
will set the SEM’s IP address to 192.168.0.1 and the netmask will remain 255.255.255.0.
The command:
ip 192.168.1.164 255.255.255.192
will set the SEM’s IP address to 192.168.1.164 and will change the netmask to
255.255.255.192. The
ip
command without any parameters will display the current
setting of the IP address and netmask. The SEM includes a simple
ping
command that
can be used to test the IP address and routing table settings.
The
route
command is used to modify and display the IP routing table entries in
environments where the SEM must send data to devices not on its subnet. To display the
routing table, use the
route list
command. There will always be one entry in the routing
table that corresponds to the IP address in the SEM. For most applications, if any routing
table entries are required, it will be sufficient to set a default route. To set the default
route, use the command:
route add default <gwaddr>
where <gwaddr> is the IP address of the default gateway (usually a router or routing
host). To remove the default route, use the command “route del default”. To add a route
to a particular network or host, use the command “route add <gw> [<netmask>]”,
“<gw>” is the IP address of the gateway, and the optional “<netmask>” is the netmask
which defines the destination network.
Filtering
On typical networks a fair amount of traffic can be made up of multicast or broadcast
packets that do not need to be transmitted over the entire network. The SEM allows
multicast or broadcast or both packet types to be filtered or ignored by the SEM. When
filtering is turned on, the filtered packet types will not be sent across the wireless link to
the other SEM(s).
DHCP
A DHCP server also can be used to set the SEM IP address as well as the default route IP
address. This is accomplished by setting the desired default route IP address in the DHCP
server using Option 3. A DHCP server will not overwrite a previously entered default
router IP address in the SEM. If a DHCP server is not used to set the default router IP
