SS7 is the signaling protocol used between SMSCs in
the core GSM network. It can carry SMS messages using the SS7/MAP
protocol. SS7 works through ISDN lines or through IP. The IP version
is not as widely used as the ISDN version. The IP version of SS7 is
Concerning performance, one SS7 link can carry between 12-18 SMS messages
per second. If you use four SS7 links at a time, you can carry around 60-70
messages per second. On an E1 connection, you can take up to 30 SS7 links,
but practically you may not get more than 16 links. This means that the
real speed limit of an SS7 over E1 connection is around 240-300 SMS per second.
Paradoxically Sigtran may give you lower performance, since all the
processing load is on your main CPU (rather than offloaded to a
specialized SS7 board.
If you connect your Ozeki NG SMS Gateway system to an SMS service provider, that
connects to the SS7 network through a single E1 line, your maximum speed will
not exceed 300 SMS per second even if you use the provider's full throughput.