From 4ae2bac4eeeda63df03dc002c8502956241fbfe7 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Mon, 27 Dec 2021 12:53:11 +0100 Subject: OsmoDevCall on ETSI V5 --- 2021/osmodevcall-v5/fujitsu_dtw_alian_photo.jpg | Bin 0 -> 628877 bytes 2021/osmodevcall-v5/g964_figure11_dl_mgmt.png | Bin 0 -> 123191 bytes 2021/osmodevcall-v5/g964_figure13_frame_relay.png | Bin 0 -> 110961 bytes .../g964_figure14_pstn_user_port.png | Bin 0 -> 60417 bytes 2021/osmodevcall-v5/g964_figure2_architecture.png | Bin 0 -> 124226 bytes 2021/osmodevcall-v5/g964_figure31_isdn_model.png | Bin 0 -> 113327 bytes 2021/osmodevcall-v5/g964_figure32_ctrl_pstn.png | Bin 0 -> 54075 bytes 2021/osmodevcall-v5/g964_figure4_l1_l2_fsm.png | Bin 0 -> 100069 bytes 2021/osmodevcall-v5/g964_figure6_protocol_arch.png | Bin 0 -> 125817 bytes .../g964_figureB1_pstn_originating_call.png | Bin 0 -> 107910 bytes .../g964_figureB2_pstn_terminating_call.png | Bin 0 -> 101318 bytes .../g964_table24_pstn_steady_state.png | Bin 0 -> 203972 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b/2021/osmodevcall-v5/nokia_eksos_subrack.png differ diff --git a/2021/osmodevcall-v5/osmodevcall-etsi_v5.adoc b/2021/osmodevcall-v5/osmodevcall-etsi_v5.adoc new file mode 100644 index 0000000..784869e --- /dev/null +++ b/2021/osmodevcall-v5/osmodevcall-etsi_v5.adoc @@ -0,0 +1,420 @@ +Retronetworking: ETSI V5 interface in PSTN +========================================== +:author: Harald Welte +:copyright: 2021 by Harald Welte (License: CC-BY-SA) +:backend: slidy +//:max-width: 45em + +== Overview + +What this talk is about + +* Retronetworking +* digital telephony switching of the 1990ies +* my research into ETSI V5 +* writing FOSS code for the LE side to talk to real-world AN + +== General Acronyms / Definitions + +[horizontal] +TE:: Terminal Equipment (Phone, Modem, ...) +NT:: [ISDN] Network Termination (e.g. NTBA in Germany) +ISDN:: Integrated Services Digital Network +PSTN:: Public Switched Telephony Network +BRA:: Basic Rate (ISDN) Access (2x 64k B-Channels) +PRA:: Primary Rate (ISDN) Access (30x 64k B-Channels) +E1:: Primary Rate interface, 2048 kBps + +== History of telephone exchanges + +* 1878: manually switched +* 1900: electromechanically switched +* 1965: electronic switching, analog +* 1976: digital switching + +== Trends in PSTN networks since ~ 1970 + +* more and more telephone subscribers (and hence, lines) +* capacity of switches increases as technology proceeds +* operational cost of each exchange is substantial +* trend towards centralization of exchanges +** fewer exchanges (= switches) +** more subscribers per exchange + +This creates the problem of managing a vast amount of subscriber line wiring + +Response: Modular architecture + +== Modular Digital Telephone Exchange + +* don't connect every subscriber local loop to a line card in the exchange +* have remote _access multiplexers_ aggregating subscriber lines +* reduces amount of cables terminating at a single geographical location +* helps reducing the subscriber loop length +* helps increasing capacity of the exchange by attaching more remote subscribers without the need of more + exchanges + +Vendors came up with their respective proprietary access multiplexers. + +ETSI V5 is the attempt to replace vendor proprietary access multiplexers with an interoperable, +standards-based system. + +== The V5 AN / LE functional split + +V5 _disaggregates_ the telephone exchange into two parts: + +* *Access Network (AN)* +* *Local Exchange (LE)* + +image::g964_figure14_pstn_user_port.png[width=1800,align="center"] + +The E1 based V5 interface can of course be carried over higher-order PDH/SDH + +== The V5.1 architecture + +image::g964_figure2_architecture.png[width=1400,align="center"] + +== V5 Acronyms / Definitions + +[horizontal] +AN:: Access Network +LE:: Local Exchange +FE:: Functional Element +LT:: Line Termination +LC:: Line Circuit +ET:: Exchange Termination + + +== V5.related 1 specifications + +* V5.1 interface +** ITU-T G.964 +** ETSI ETS 300 324-1 +** ETSI TR 150 +* Q3 interface (management) +** ITU-T Q.512 +** ETS ETS 300-376-y, ETS 300 378-y (Q3AN) +** ETS ETS 300-377-z, ETS 300 379-z (Q3LE) + +== V5.1 Protocol Stack + +== V5.1 Protocol Architecture + +image::g964_figure6_protocol_arch.png[width=1400,align="center"] + +== LAPV5: Data Link Layer + +image::g964_figure11_dl_mgmt.png[width=1300,align="center"] + + +== Control Protocol + +* Common Control +** Re-provisioning +** Switch-over to new variant +** Restart +* Per-Port Control +** Blocking +** Unblocking +** Activation / Deactivation (ISDN only) + +== Control Protocol (PSTN) + +* administrative blocking / unblocking +** UNBLOCK + ACK +** BLOCK + ACK +** Functional Elements FE201-FE205 used + +== Control Protocol (ISDN) + +* administrative blocking / unblocking +** UNBLOCK + ACK +** BLOCK + ACK +** Functional Elements FE101-FE106 and FE201-FE208 used +** D-CHANNEL BLOCK/UNBLOCK +* access activation +** ACTIVATE ACCESS +** DEACTIVATE ACCESS +* miscellaneous +** PERFORMANCE GRADING + +== PSTN subscriber + +* _Control Protocol_ handles low-level physical layer management +* _PSTN Protocol_ handles analog siganling (on-hook/off-hook, pulse dialing) + +image::g964_figure14_pstn_user_port.png[width=1800,align="center"] + +== PSTN protocol + +* analogue line states +* timing and duration of analogue signals +* voltage/frequency of metering pulses +* ringing current +* FSMs for AN and LE side +* Messages In PSTN protocol +** ESTABLISH + ESTABLISH-ACK +** SIGNAL + SIGNAL-ACK +** DISCONNECT + DISCONNECT-COMPLETE +** STATUS + STATUS-ENQUIRY +** PROTOCOL-PARAMETER + +== PSTN protocol - Originating Call + +image::g964_figureB1_pstn_originating_call.png[width=1300,align="center"] + +== PSTN protocol - Terminating Call + +image::g964_figureB2_pstn_terminating_call.png[width=1300,align="center"] + +== PSTN protocol - Example IE + +image::g964_table24_pstn_steady_state.png[] + +== ISDN subscriber + +image::g964_figure31_isdn_model.png[width=1300,align="center"] + +== ISDN subscriber + +* _Control Protocol_ handles low-level physical layer management +* _Frame Relay_ forwards Q.921 (LAPD) over V5 +** Actual ISDN L2 (Q.921) and L3 (Q.931) processing all in LE +** not to be confused with the Packet WAN technology Frame Relay! + +As ISDN already has digital signaling (Q.921/Q.931), no need for any V5 specific ISDN protocol (like PSTN +protocol). Signaling from user is _relayed_ to LE via V5 (and vice-versa). + +== ISDN LAPD Frame Relay + +image::g964_figure13_frame_relay.png[width=1300,align="center"] + +== Control protocol - ISDN port activation + +[mscgen] +---- +include::isdn-control.msc[] +---- + + + +== V5.2: Successor of V5.1 + +V5.2 introduces the following major changes: + +* up to 16xE1 per V5.2 interface (V5.1: 1xE1) +* support for ISDN PRA (Primary Rate Access) subscribers +* concentration (overprovisioning of local loop vs V5 circuits) +* fail-over between links + +The new features are added in a backwards compatible manner + +== The V5.2 architecture + +image::g965_figure2_architecture.png[width=1300,align="center"] + + +== V5.2 specifications + +All of the V5.1 related specs plus the following new ones: + +* ITU-T G.965 +* ETSI ETS 300 347-1 + + +== V5.2 Protocol Stack + +* LAPV5 Data Link Layerlike in V5.1 +* L3 protocols like in V5.1 (PSTN, control) +* additional, new L3 protocols on top of LAPV5 +** link control protocol +** protection protocol +** BCC (Bearer Channel Connection) + + + +== V5.2 Protocol Architecture + +image::g965_figure6_protocol_architecture.png[width=1400,align="center"] + +== V5.2 BCC + +* dynamically allocate B-channels on V5 to B-channels of subscribers +* messages +** ALLOCATION + COMPLETE / REJECT +** DE-ALLOCATION + COMPLETE / REJECT +** AUDIT + COMPLETE +** AN FAULT + ACK +** PROTOCOL ERROR + +== V5.2 link control protocol + +* identification of different links in V5.2 interface +* blocking and coordinated unblocking of V5.2 links + +== V5.2 protection protocol + +* fail-over between different E1-links on V5.2 interface +* monitoring of flag, data link layer establishment +* mapping of logical / physical channels + +== Q3 interface (management) + +* Full Complex ISO/OSI protocol Stack + +image:q812_q3_upper_layer_stack.png[] + +== Nokia EKSOS + +* Nokia EKSOS N20: 512 bearer channels, 17-slot rack +* important modules +** Node Control Unit +** PSTN unit (32xPSTN) +** ISDN BRA U-interface unit (16xU) +** TR2M4 unit (4xE1) +* NodeManager software + +== Nokia EKSOS N20 + +image:nokia_eksos_n20_photo.jpg[width=1300,align="center"] + +== Nokia EKSOS N20 Node Control Unit + +image:nokia_eksos_ncu.png[width=1000,align="center"] + +== Nokia EKSOS PSTN + ISDN Unit + +image:nokia_eksos_pstn_isdn.png[width=850,align="center"] + + + +== Fujitsu/DeTeWe ALIAN + +* Most common modules in FSX2000 +** MPU-H (Main Processor Unit) +** HOS (Housekeeping, subscriber line test) +** NMI (Network Management Interface) +** TSA (Trunk to tributary cross-connect) +** V5MC (V5.2 termination message control) +** BRA12T (12x ISDN U) +** SLM15G (15x POTS line) +** E1B21 (21x E1 trunk or tributary) +** E1BU4 (4x E1 trunk or tributary) +* FLEXR management software + +== Fujitsu/DeTeWe ALIAN + +image:fujitsu_dtw_alian_photo.jpg[width=1300,align="center"] + +== Keymile MileGate + +Keymile MileGate is a combined POTS/ISDN/DSL subscriber access platform + +* Most common V5 related modules +** PCOM1/2 (V5 AN) +** TUXA1 (12x POTS) +** SUIT1 (16x ISDN PRA U) +** SUPx4 (48x POTS) + +== Siemens FastLink ONU + +* Most common V5 related modules +** IUL84 (8x ISDN BRA) +** SUB102 (10x POTS) +** SUB162 (16x POTS) +** SUB322 (32x POTS) + +== The V5 master plan + +* collect decommissioned V5 access multiplexers +* create some kind of working setup out of them +** similar to the PBX-based _Osmocom retronetworking_ setup at last xxC3 +* deploy that at future hacker events +** allow retronetworking interested people to get analog and Uk0 subscriber lines + +== Required for V5 master plan + +* V5 Access Multiplexers (almost done) +* Equipment documentation (done) +* Configuration/Mgmt Software (done) +* E1 interface (done, icE1usb or DAHDI cards) +* V5 protocol stack for LE side (in progress) +** not supported in FreeSwitch, Asterisk or even yate +** at least a wireshark disector exists (yay!) + +== Towards a FOSS implementation for V5 LE role + +* started an implementation of the LE side of V5 +* based around libosmocore and its TLV decoder + FSM +* current status (WIP, about 3k lines of code) +** core data structures +** Control protocol encoding + decoding +** Common Control FSM +** Port control FSM +** V5.2 Link Control Protocol FSM + +Waiting for actual V5 AN equipment to start testing it. + +== V5 LE PBX integration + +* how to integrate with PBX? +** we definitely want to reuse Q.921 + Q.931 of these +** B-channels could be accessed directly via DAHDI +** D-channels would need to go through _Frame Relay_ de-concentration first + +[graphviz] +---- +digraph G { + rankdir=LR; + subgraph cluster_AN { + subgraph cluster_subA { + label="Subscriber A"; + TE_A; + NT_A; + TE_A -> NT_A [label="S0"]; + } + subgraph cluster_subB { + label="Subscriber B"; + TE_B; + NT_B; + TE_B -> NT_B [label="S0"]; + } + subgraph cluster_subC { + label="Subscriber C"; + TE_C; + } + subgraph cluster_subD { + label="Subscriber D"; + TE_D; + } + AN; + NT_A -> AN [label="U"]; + NT_B -> AN [label="U"]; + TE_C -> AN [label="POTS"]; + TE_D -> AN [label="POTS"]; + } + + subgraph cluster_LE { + label="LE"; + DAHDI [shape="record",label=" DAHDI | TS1 | TS2 | TS15 | TSn"]; + PBX [label="PBX\nQ.921\nQ.931"]; + V5D [shape="diamond"]; + + DAHDI:TS15 -> V5D [label="V5"]; + DAHDI:TS1 -> PBX [label="B-Channel"]; + DAHDI:TS2 -> PBX [label="B-Channel"]; + DAHDI:TSn -> PBX [label="B-Channel"]; + + V5D -> PBX [label="LAPDm Sub A"]; + V5D -> PBX [label="LAPDm Sub B"]; + V5D -> PBX [label="PSTN Ctrl Sub C"]; + V5D -> PBX [label="PSTN Ctrl Sub D"]; + } + AN -> DAHDI:DAHDI [label="E1"]; +} +---- + + +== EOF + +End of File diff --git a/2021/osmodevcall-v5/q812_q3_upper_layer_stack.png b/2021/osmodevcall-v5/q812_q3_upper_layer_stack.png new file mode 100644 index 0000000..30d56b1 Binary files /dev/null and b/2021/osmodevcall-v5/q812_q3_upper_layer_stack.png differ -- cgit v1.2.3