Mobicents Summit 2012 - Dmitri Soloviev - Telscale SS7 Card
Telscale SS7 cardPart 1: long intro ● SS7, Sigtran and TDM ● What is it? G.704 structure ● Who are competitors? ● How long TDM will survive?Part 2: Telscale SS7 card ● Architecture ● Use cases ● Software structure ● Current state & Goals
Telscale SS7 cardjSS7 and Telscale Card CAMEL MAP ISUP TCAP SCCP →a card to convert SS7 into Sigtran (M3UA, M2UA, M2PA) M3UA MTP3 → support media (MGCP+G.711) SCTP TCP MTP2 → G.703 to SIP gateway → G.703 probe Ethernet HW
Telscale SS7 cardE1, T1 etc ● G.703 — pulse shaping, masks ● Bipolar coding with clock recovery (HDB-3 for E1) ● Sequence of bits TS31 TS0 TS0 TS0 TS0 TS0 TS0 TS0 TS0 TS1 TS1 bit 7 bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 bit 0 bit 1 ● 32 channels (time slots), 8 bits each ● Time slot 0: G.704. Dedicated content ● A time slot is a 64k channel: SS7 link, G.711 voice or whatever ● Quality monitoring: PBV (code errors) + CRC-4 (timeslot 0) .. and why do they call it G.703?
Telscale SS7 cardCards at the Market● Dialogic – sophisticated card with CPU onboard – voice and signaling onboard – OS driver, API● Digium (Asterisk) – low cost card w/o inteligence – OS driver, interfaces timeslots to host CPU● Telscale Card – NO drivers: stand-alone system with Ethernet interfacing – DSP running uClinux: DSP interfaces(SPORT) + power of linux
Telscale SS7 cardIs there a Market?● GSM world (various SS7 apps with or w/o voice) – initial GSM specs; available everywhere – too much was invested● Interfacing existing PBXs (ISDN ↔ SIP) .. how long G.703 will survive? .. how long will SS7 live?
Telscale SS7 cardUse Cases → PCM terminal ● Set of SS7 terminals ● SS7 terminals + optional Voice ● ISDN ↔ SIP → SS7 probe for various apps
Telscale SS7 cardSoftware Structure Part 1 An embedded system with FPGA and linuxFlexible Schematics that→ must be configured (from SPI flash)to “build” a “hardware”→ DSP can “reload” a new schematics(@another offset)→ SPI content can be changed Linux system that has → a flexible boot loader → linux + applications
Telscale SS7 cardSoftware Structure Part 2 → Various SS7/Sigtran stacks in parallel M3UA → SS7 links are distributed M2UA M2PA via shared memory → “multiplexing” works with array of time slots, SS7 links via SHM ea ether → processes time slot as SS7 link “Multiplexing” → controls time slot via MGCP (ea media) → each driver interfaces PCM driver PCM driver a PCM line
Telscale SS7 card Current state & Goals → deployed already → production state, commercially available Production (now) → fixing production cycle and logisticsOptimization (Q412) Features(Q113) → driver re-design (char → MMAP) → M2PA for card → moving part of MTP2 to FPGA → M2PA for jSS7 USABILITY → user-friendly configuration FEATURES → SCTP Multihoming → M2UA/M2PA ? → T1 if requested → pseudo-interfaces for wireshark VOICE → MGCP+RTP → DTMF+ECHO