1, 新增 SIP Provider，在 conf/sip_profiles/external 里面增加该配置文件
<!-- sipprovider.xml -->
<include>
<gateway name="sipprovider">
<param name="username" value="user"/>
<param name="password" value="pass"/>
<param name="realm" value="*"/>
<param name="proxy" value="sipprovider_ip_addr"/>
<param name="register" value="true"/>
<param name="expire-seconds" value="600"/>
<param name="ping" value="30" />
<param name="sip-trace" value="true" />
</gateway>
</include>
这个 SIP Provider 要求 REGISTER，另外因为 freeswitch 是透过 NAT 访问，因此设置 30 秒发送 ping。
2, 将这个 SIP Provider 提供的 DID 映射到相应的 extension 上
SIP Profile external.xml 设定了 context 默认为 public，因此我们需要编辑 conf/dialplan/public.xml
<extension name="sipprovider"> <!-- your provider or any name you'd like to call it -->
<condition field="destination_number" expression="xxxxxxx"> <!-- your DID for this gateway-->
<action application="transfer" data="1001 XML default"/>
</condition>
</extension>
备注：
也可以在 directory 里面配置这个 gateway，两种配置的区别可以看看这个连接
http://wiki.freeswitch.org/wiki/Clarification:gateways
<anthm> if you put them in a user tag in your directory you can then tell
#
sofia to manage the whole domain and it will iterate all the users
#
in that domain and reg the gateways
#
<anthm> if you don't need that you can just put them in the sofia conf
What I gather from this is that if you only want certain extensions to be registered with your voip provider when a specific user registers with freeswitch you should define gateways in the directory section rather than in the
sofia configuration. Conversely, if you always want an extension registered with a provider you would define the gateway as part of the sip profile.
3, 设定 extensions 可以通过这个 SIP Provider 拨打 PSTN 电话
conf/dialplan/default.xml
<extension name="Long Distance">
<condition field="destination_number" expression="^00(/d+)$">
<action application="set" data="effective_caller_id_number=xxxxxxxx"/>
<!-- If your provider does not provide ringback (180 or 183) you may simulate
ringback by uncommenting the following line. -->
<!-- action application="ringback" /-->
<action application="bridge" data="sofia/gateway/sipprovider/1550$1"/>
</condition>
</extension>
注意：应该将新增的配置放置在下面信息以前
<!--
WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
Anything you put below this line will usually get ignored due to the file in
default/99999_enum.xml as it will transfer the call to the enum dialplan.
WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
-->