RTMMoIP Alfredo Terzoli / Mosiuoa Tsietsi

PLAN Defining the softswitchDefining the softswitch An example softswitch: iLangaAn example softswitch: iLanga The core of iLanga: AsteriskThe core of iLanga: Asterisk

Softswitch in action! As an aside, a bit of SS7 terminology SSP: Service Switching Point (also called ‘central office switch’) SCP: Service Control Point STP: Signal Transfer Point

Softswitch: a simple definition ‘Switching’ in classic telephony is the connection of one telephone user to another‘Switching’ in classic telephony is the connection of one telephone user to another Initially done manually, it has become more and more complex and sophisticatedInitially done manually, it has become more and more complex and sophisticated The ‘switch’, the network element doing the switching, has become over the years the cornerstone of telephony networksThe ‘switch’, the network element doing the switching, has become over the years the cornerstone of telephony networks If the job of switching is done in software, uses packet networks and support multiple protocols, the switch is called SOFTSWITCHIf the job of switching is done in software, uses packet networks and support multiple protocols, the switch is called SOFTSWITCH

Softswitch: functions “According to the International Softswitch Consortium, a softswitch should be able to“According to the International Softswitch Consortium, a softswitch should be able to –(1) control connection services for a media gateway and/or native IP endpoints –(2) select processes that can be applied to a call –(3) provide routing for a call within the network based on signaling and customer database information –(4) transfer control of the call to another network element and –(5) interface to and support management functions such as provisioning, fault, billing” ( )

Softswitch: metapoints Essentially, the softswitch is needed to make the new network ‘recognizable’ by Telco operatorsEssentially, the softswitch is needed to make the new network ‘recognizable’ by Telco operators Less important from the point of view of people with data networking background (Internet), but still usefulLess important from the point of view of people with data networking background (Internet), but still useful Not a ‘hard and fast’ definitionNot a ‘hard and fast’ definition Term very much used in the industry currentlyTerm very much used in the industry currently

Transformations (still metapoints…) International Softswitch Consortium ( International Softswitch Consortium (  International Packet Communication Consortium ( International Packet Communication Consortium (  IMS Forum ( Forum ( IP Multimedia Subsystem? Check it out at Multimedia Subsystem? Check it out at

Softswitch: benefits Flexibility, naturally, as one should expect from a software artefactFlexibility, naturally, as one should expect from a software artefact Generality: every known telephony technology is supposed to be able to attach with the appropriate adapterGenerality: every known telephony technology is supposed to be able to attach with the appropriate adapter Cost reduction: it might sound strange, but it has to do with the very expensive Telco traditional equipmentCost reduction: it might sound strange, but it has to do with the very expensive Telco traditional equipment

Softswitch: typical architecture Although strictly not necessary, softswitches are often decomposed into:Although strictly not necessary, softswitches are often decomposed into: –call control –media transport –services The decomposition is often physicalThe decomposition is often physical Practical example, the Verso system downstairs, in the ‘fish-bowl’ next to the entrancePractical example, the Verso system downstairs, in the ‘fish-bowl’ next to the entrance

iLanga: a small softswitch Asterisk GnuGK iLanga proxy iLanga Core Legacy PBX BRI PRI PSTN BRI PRI SIP IAX H.323 MGCP Local VoIP Endpoints SER Internet

Main components SER, Sip Express Router: Sip Express Router: Asterisk : : GnuGK (or OpenH323 Gatekeeper): (or OpenH323 Gatekeeper):

Questions?