B&B Electronics VFG3000 - Manual - Manual (Page 52)

W ORKING WITH M ODEMS V LINX F IELDBUS G ATEWAY M ANAGER U SER M ANUAL
P AGE 36
SMS M
ESSAGE
P
ROCESSING
When SMS messaging is enabled, the Gateway will instruct the GSM modem to check for
new incoming or outgoing messages every five seconds. Incoming messages are forwarded to
the mail manager, which will optionally forward them to other users according to its
configuration. Note that it is not possible to check for messages while the modem is
connected to a CSD or GPRS session, so you will want to avoid using permanent connections
when working with SMS. Note also that if more than one GSM modem is configured, all will
be able to receive messages, but only the second modem will be used for sending.
U SING M ULTIPLE I NTERFACES
Each Fieldbus Gateway can support up to two modem independent connections. When
combined with the Ethernet port, this gives a total of up to three distinct IP interfaces, all of
which will operate according to the configuration parameters defined for each connection.
This section describes how these multiple interfaces will interact, and how the Gateway will
decide where to send each packet of data.
I NTERFACE S ELECTION
Each interface has an IP address and a network mask, which are used to decide whether to
forward packets to that interface. For example, if the Ethernet interface is configured with an
IP address of 192.168.1.0 and a network mask of 255.255.255.0, any packets for IP addresses
starting with 192.168.1 will be sent to this interface. Likewise, if an on-demand modem
connection has a remote IP address of 192.168.2.2 and a netmask of 255.255.255.255,
sending a packet to address 192.168.2.2 will result in the connection being established.
D EFAULT R OUTE
In addition, one single interface may also define a default route, which will be used to handle
packets that do not specifically match any other interface. The method used to configure the
route varies according to the interface type, as shown in the table below…
I NTERFACE T O D EFINE D EFAULT R OUTE
Ethernet Enter a non-zero value for the Gateway property.
Dial-In Enter 0.0.0.0 for the Remote Mask.
Dial-Out Select Default Gateway for the Route Type property
Note again that only a single interface may define a default route. For example, a Fieldbus
Gateway may be connected to a number of Ethernet devices using an IP address of
192.168.1.0 and a netmask of 255.255.255.0, with no gateway defined. An on-demand
modem connection may be configured to access an Internet Service Provider so as to send
alarm emails. Its Route Type is set to Default Gateway, making it the route for any packets for
IP addresses that do not match the network defined for the Ethernet port. The SMTP server is
configured as 24.104.0.39, resulting in a dial-out connection when an attempt is made to send
a message.