osmodevcon: welcome, SD-E1, retrospective

2018/osmodevcon2018-2017_retrospective/osmodevcon2018-2017_retrospective.adoc

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+Year 2017 Osmocom retrospective
+===============================
+:author:	Harald Welte <laforge@gnumonks.org>
+:copyright:	2018 by Harald Welte (License: CC-BY-SA)
+:backend:	slidy
+:max-width:	45em
+
+== 2017 - a year of change
+
+Osmocom CNI (Cellular Network Infrastructure) has changed a lot:
+
+* software changes
+* team / developer changes
+* sysmocom company focus changes
+
+== 2017 - CNI Software changes
+
+* OsmoBSC migration from SCCPlite to 3GPP AoIP
+* OsmoMGW as integral part of both BSC and MSC
+* NITB split into separate MSC, HLR, BSC
+* 3G (IuCS, IuPS) goes mainline
+
+== 2016/2017/2018 - Team changes
+
+* Q1 2016: Jacob Erlbeck leaves sysmocom
+** unfortunately a complete loss to Osmocom, particularly OsmoPCU
+* 2017: Holger Freyther leaves sysmocom
+** unfortunately also shift of focus away from Osmocom :(
+** immense loss to the project in terms of skill and capacity
+* Q1 2018: Max Suraev leaves sysmocom
+** another loss of lots of Osmocom knowledge
+
+== sysmocom changes
+
+* we used to have to do lots of non-Osmocom work to cross-subsidize Osmocom
+** big distraction of resources in 2014/2015, now gone
+* we used to cross-subsidize Osmocom development by hardware sales
+** not happening as much anymore
+* we now work almost 100% on Osmocom
+** R&D projects, support contracts and grants
+
+== split NITB aftermath (the good parts)
+
+* biggest architectural change since we started in 2008
+* lots of good reasons and design improvements
+** finite state machines with proper timeouts / clean-up
+** proper 3GPP AoIP with interoperability tesing
+** no synchronous HLR database access
+** HLR access from OsmoMSC and OsmoSGSN
+** 2G/3G authentication over GERAN and UTRAN
+
+== split NITB aftermath (the bad parts)
+
+[role="incremental"]
+* never-ending list of breakage
+** actual regressions of things that used to work before
+** things that were _known omissions_ during the restructuring
+* some commercial users stuck with SCCPlite and thus old @osmo-bsc-sccplite@
+** almost none of the new features or bug fixes there
+** no automatic testing
+** back-ports time-consuming
+
+== split NITB aftermath (lessons learned)
+
+* overall complexity of Osomcoom cellular is quite stunning now
+* absence of proper functional testing has caused massive fall-out
+* the split architecture allows for betteer testing of smaller parts of the system
+* my personal main focus of the last 5+ months:
+[role="incremental"]
+** testing, testing, testing, testing
+** testing, testing, testing, testing
+** some more testing
+** even more testing
+
+
+== Osmocom CNI testing (1/2)
+
+[role="incremental"]
+* unit test (autotest, like we always had)
+** test individual functions / APIs of libraries / programs
+** executed during "make check" and hence before any patch can get merged
+* automatized functional tests in TTCN-3
+** test _external_ visible behavior on interfaces such as Abis, A, GSUP, GTP, MNCC, PCUIF, CTRL, VTY, ...
+** executed nightly by Jenkins (could be more frequently)
+
+== Osmocom CNI testing (2/2)
+
+[role="incremental"]
+* osmo-gsm-tester
+** tests entire Osmoocom network with BTS/BSC/MSC/HLR/PCU/SGSN/GGSN/...
+** uses real BTS + MS hardware (over coaxial cable)
+** automatic execution multiple times per day
+* interop tests
+** against NG40 RAN + CN simulator from NG4% (A / Gb / Iu level)
+** not fully automatized yet
+
+
+== Osmocom project health (CNI)
+
+[role="incremental"]
+* lots of funded developments, *but*
+** primarily _enterprise features_ required by professional users
+* dominance of sysmocom is problematic
+** sustainable FOSS has no single point of failure!
+* we need more contributions from third parties
+** particularly those that benefit commercially from Osmocom
+
+== Osmocom project health (other projects)
+
+[role="incremental"]
+* OsmocomTETRA dead since 2012, occasional small fixes
+* No OsmocomBB ports to other PHY/chip yet
+* OsmocomDECT completely dead
+* Erlang core network projects dead
+* Smalltalk projects dead (AFAICT)
+* SIMtrace dead for years, about to be resurrected
+
+== Osmocom project health (other projects)
+
+[role="incremental"]
+* gr-osmosdr very low commit ratio
+* rtl-sdr no commits in 2015-2017
+* but it's not that bad... (see next slide)
+
+== Osmocom project health (other projects)
+
+[role="incremental"]
+* gr-gsm, fake_trx and trxcon a welcome change in OsmocomBB
+* osmocom-analog (jolly to the rescue)
+* osmo-fl2k (soon! now! this year!)
+
+== Osmocom status (CNI)
+
+[role="incremental"]
+* CS RAN (BTS, BSC) is quite strong/complete these days
+** ready to be used with 3rd party CN
+* PS RAN (PCU) suffers from lack of attention
+** lack of automatic testsuite with decent coverage
+** lack of uplink multi-slot any many EGPRS features
+* CS CN (MSC, HLR) 
+** in halthy state, but lack of TCAP/MAP interface limits us to non-roaming networks
+* PS CN (SGSN, GGSN) 
+** in good health, now with IPv6 supoprt and kernel GTP acceleration
+
+== Osmocom outlook (CNI)
+
+* 2G still in demand by lots of use cases (rural, maritime, ...)
+** if we had TCAP/MAP interface, many more deployments possible
+* 3G has some users but lack of FOSS RNC limits us to femtocells
+* 4G is deployed in parallel to 2G in many scenarios
+** Osmocom 2G stack needs 2G-4G integration (SGs, DIAMETER)
+** Osmocom needs to contribute  to FOSS 4G projects (nextepc, srsLTE)
+* irony: Now that it's possible to do properly funded Osmocom development, we have less people involved than in the early days :(
+
+If we don't manage to focus on 4G soon, interest in 2G will diminish soon
+
+== Osmocom outlook (other projects)
+
+[role="incremental"]
+* activity of original/traditional Osmocom developers decreased
+* without attracting more developers, a lot of projects will remain dormant and/or never realize their potential
+* I'd love to work on TETRA, DMR or other mobile communications technology
+** but lack of developers and contributors even for 2G makes me stuck in 2G CNI land :(
+
+== Personal Request
+
+[role="incremental"]
+* Osmocom needs you!
+* we've lost too many friends already
+* please don't leave Osmocom; please don't leave me
+
+== Further Reading
+
+See my detailed 2017 review:
+
+* http://osmocom.org/news/84
+
+== EOF
+
+End of File

2018/osmodevcon2018-software_defined_e1/osmodevcon2018-software_defined_e1.adoc

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+Software Defined E1
+===================
+:author:	Harald Welte <laforge@gnumonks.org>
+:copyright:	2018 by Harald Welte (License: CC-BY-SA)
+:backend:	slidy
+:max-width:	45em
+
+== E1 / T1 / TDM
+
+* good old ISDN technology
+* 2 Mbits/s (E1) or 1.54 Mbits/s (T1) synchronous, full-duplex
+* not used much anymore in telephony (everything moves to SIP/IP)
+* still used quite a bit in 2G/3G cellular networks, even in 2018!
+
+== E1/T1/TDM in 2G/3G networks
+
+traditionally all interfaces over E1/T1
+
+* Abis (RSL/OML over LAPDm) from BTS to BSC
+* A (BSSAP/SCCP/MTP) from BSC to MSC
+* ISUP/MTP for calls between MSCs and from/to PSTN
+* MAP/TCAP/SCCP/MTP between MSC/VLR, SGSN, HLR, GW-MSC, IW-MSC, ...
+* Gb (BSSGP/NS/FR) betewen PCU and SGSN
+* Iub (Inverse ATM multiplex) over 4xE1 to RNC
+
+== E1/T1/TDM in 2G/3G networks today: Abis
+
+* TDM based Abis on decline
+** back-haul networks increasingly switch TDM to IP as 4G is co-located with 2G
+** but: Lots of BTSs still have physical E1
+** Equipment like Ericsson SIU used to convert E1 to IP (proprietary protocols)
+** TDM link remains between BTS and SIU-style converter
+
+== E1/T1/TDM in 2G/3G networks today: A
+
+* TDM based A on the decline
+** 3GPP has an official interoperable protocol: AoIP
+** adopted by many more modern MSCs
+** OsmoBSC supports 3GPP AoIP (yay!)
+
+== E1/T1/TDM in 2G/3G networks today: Core
+
+* TDM based core network connections still prevalent
+** lots of legacy switches (MSCs) and STPs around
+** signaling interconnect among MNOs and MVNOs often still TDM
+** full MAP+CAP over TCAP/SCCP/MTP stack required
+
+== E1/T1/TDM interfacing from Linux / Osmocom
+
+* we've had E1/T1 based Abis for ages
+* **libosmo-abis** supports mISDN + DAHDI drivers
+** PCI + PCIe cards readily available
+** still extremely expensive (OK in CN, not next to each BTS)
+** PCI cards of course require a rather large (ATX, ITX, ...) computer
+
+[graphviz]
+----
+digraph G {
+  rankdir = LR;
+  XFMR [label="Magnetics"];
+  BTS -> XFMR [label="E1"];
+  subgraph cluster_A {
+    label = "Classic E1/T1 Adapter (PCI/PCIe)";
+    XFMR -> LIU [label="E1 (HDB3)"];
+    LIU -> TDMCTRL;
+    TDMCTRL -> Bridge [label="Parallel Bus"];
+  }
+  Bridge -> CPU [label="PCI / PCIe"];
+}
+----
+
+* TDMCTRL implements equalizer, elastic buffer, CRC, framing, HDLC, ...
+
+
+== Osmocom E1/T1/TDM interfacing use-case
+
+* many E1/T1 based BTSs decommissioned around the world
+* refurbished traders have quantities in stock for *very* low price
+* using those BTSs with OsmoBSC + friends is an inexpensive way of
+** deploying carrier-grade tier-1 BTS equipment
+** with excellent environmental, RF sensitiviy, RF power and high MTBF
+** for very low cost
+* but: The E1/T1 card + associated PC are more expensive than your BTS :(
+
+== E1/T1/TDM interfacing wishlist
+
+* in 2018, you just want a very small E1/USB or E1/Ethernet adapter
+* can be used with laptop when on the road, debugging something
+* can be used with Raspberry Pi, Beaglebone or whatever other mall, inexpensive embedded Linux board
+* you want to pay a realistic price, not some fantasy price (Digium & co)
+
+== Building an E1/T1 adapter
+
+Ok, so let's build an E1 adapter using existing chips...
+
+* existing E1/T1 controllers
+** many (including Infineon) already EOL due to the demise of ISDN
+** have arcane bus interfaces (parallel Intel/Motorola bus like 1980)
+** are ridiculously expensive
+** come in very large acane packages
+
+== The SD-TDM Plan [tm]
+
+The road to software-defined E1:
+
+* Simply use a LIU (Line Interface Unit) + Magnetics
+** this converts the HDB3 ternary signal to a serial bit-stream
+* serialize/deserialize that stream from a microcontroller
+* do everything else in software, including framing, CRC4, ...
+
+[graphviz]
+----
+digraph G {
+  rankdir = LR;
+  XFMR [label="Magnetics"];
+  BTS -> XFMR [label="E1"];
+  subgraph cluster_A {
+    label = "Software Defined E1 Adapter";
+    XFMR -> LIU [label="E1 (HDB3)"];
+    LIU -> uC [label="E1 (Serial Bits)"];
+  }
+  uC -> Linux [label="Buffers of bits over\nUSB or Ethernet"];
+}
+----
+
+== Hardware Option A: TI PRU
+
+* TI processors like the AM335x on the Beagleboard have PRU cores
+** PRU: _Programmable Realtime Unit_
+* PRU allows high-speed "real time" bit banging
+* PRU can serialize/deserialize and provide buffers to ARM core with Linux
+* E1 adapter could be a beaglebone cape
+* Beaglebone could actually run entire OsmoBSC + OsmoMGW, too, using 3gPP AoIP over back-haul
+
+== Hardware Option B: XMOS
+
+* XMOS has a very unusual microcontroller architecture
+* RISC CPU core @ 500 MHz with programmable serdes
+** except USB + Ethenet, no other hard peripherals
+** all peripherals (including I2C, SPI, ..) implemented in software!
+** could be a simple / small E1/T1 to USB or to Ethernet converter
+
+== Hardware Option C: Programmable Logic
+
+* Using FPGA or CPLD one can of course synthesize a E1 core
+* but that's not really _software defined_ anymore
+* toolchain trouble (except yosys/arachne/ice40)
+* just seems like overkill for a slow 2 Mbits/s signal
+
+== Further Reading
+
+* http://osmocom.org/projects/e1-t1-adapter
+** http://osmocom.org/issues/2484
+* XMOS
+** https://www.xmos.com/download/private/Introduction-to-XS1-ports%281.0%29.pdf
+** https://www.xmos.com/download/private/XMOS-Programming-Guide-%28documentation%29%28E%29.pdf
+* TI PRU
+** http://processors.wiki.ti.com/index.php/Programmable_Realtime_Unit_Subsystem
+** http://processors.wiki.ti.com/images/1/18/PRUSS_Training_Slides.pdf
+
+== EOF
+
+End of File

2018/osmodevcon2018-welcome/osmodevcon2018-welcome.adoc

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+Welcome to OsmoDevCon 2018
+==========================
+:author:	Harald Welte <laforge@gnumonks.org>
+:copyright:	2018 by Harald Welte (License: CC-BY-SA)
+:backend:	slidy
+:max-width:	45em
+
+== Welcome
+
+* 2018 marks the 7th incarnation of OsmoDevCon
+* Great to see all of you (again)
+* Great to see some new faces, too!
+
+== OsmoDevCon
+
+[role="incremental"]
+* by developers for developers
+* as technical as it gets
+* at least as much about the people involved than the topics
+* feel free to present things beyond classic Osmocom
+* any reasonably advanced technical topic is welcome
+* ... as far as time permits
+
+== Venue
+
+* Three rooms that we can use
+** main room
+** the _rear room_ (this year with table)
+** the _PC room_ in the back
+* two washrooms/toilets
+** use load-balancing algorithm
+* basement kitchen
+** we'll put up foot catering there
+
+== Beverages / Coffee / Tea
+
+Help yourself with:
+
+* our own [filter] coffee + milk to use with the existing machine
+* tea making facilities
+* variety of beverages in the fridce
+** please keep a tally of how many bottles you consume
+** make sure to settle the total amount before you leave!
+* snacks (sweets) available on top of fridge
+** same rules as for beverages
+* cookies spread out on the meeting table(s) 
+
+== Internet Access
+
+* WiFi login / password marked on inner side of door
+* Ethernet switches available around venue, just plug in + DHCP
+** don't cause Ethernet loops (no STP!)
+
+== Important Rules
+
+* *DO NOT USE THE TAP (water) OR DISHWASHER IN THE BASEMENT*
+** you will cause a flooding if you do it anyway
+** instead, use dishwasher in the bathroom at the far back of the venue
+* be excellent to each other
+
+== Changes from 2017
+
+criticism from last year:
+
+* need more time for hacking / chat 
+* one day less was not such a good idea (so back to 4 days)
+* let's try to make use of the _rear room_ for hacking
+* we have pretalx and a real schedule!
+* we have video recordings
+
+== Sponsoring / Thanks
+
+* Lunch sponsored by sysmocom
+* Dinner sponsored by sysmocom
+* venue + internet provided by IN-Berlin e.V.
+* video recording by c3voc
+* presentations by our amazing Osmocom community
+* guest presentations by
+** Sukchan Lee (nextepc)
+** B. Jovanovic and D. Webster (LimeSDR adaptive digital predistortion)
+* 10x LimeSDR mini donated by Lime Microsystems
+
+== EOF
+
+End of File