You may configure the MTA to have more than one SMS channel. There are two typical reasons to do this:
To communicate with different SMPP servers.
This is quite straightforward: just add an additional SMS channel to the configuration, being sure to (a) give it a different channel name, and (b) associate different host names with it. For example,
sms_mway port 55555 threaddepth 20 smpp.siroe.com sms_ace port 777 threaddepth 20 sms.ace.net
Note that no new rewrite rule is needed. If there is no directly matching rewrite rule, Messaging Sever looks for a channel with the associated host name. For example, if the server is presented with email@example.com, it would look for a channel of the name “host.domain”. If it finds such a channel, it routes the message there. Otherwise, it starts looking for a rewrite rule for the “.domain” and if none is there, then for the dot (“.”) rule. For more information on rewrite rules, see Chapter 11, Configuring Rewrite Rules.
To communicate with the same SMPP server but using different channel options.
To communicate with the same SMPP server, using different channel options, specify the same SMPP server in the SMPP_SERVER channel option for each channel definition.
Using this mechanism is necessary since two different channels cannot have the same official host name (that is, the host name listed in the second line of the channel definition). To allow them to communicate with the same SMPP server, define two separate channels, with each specifying the same SMPP server in their SMPP_SERVER in their channel option files.
For example, you could have the following channel definitions,
sms_mway_1 port 55555 threaddepth 20 SMS-DAEMON-1 sms_mway_2 port 55555 threaddepth 20 SMS-DAEMON-2
and rewrite rules,
sms-1.siroe.com $u%sms-1.siroe.com@SMS-DAEMON-1 sms-2.siroe.com $U%sms-2.siroe.com@SMS-DAEMON-2
Then, to have them both use the same SMPP server, each of these two channels would specify SMPP_SERVER=smpp.siroe.com in their channel option file.