Who am I? What have I done? What am I doing?

Transcription

1 Who am I? What have I done? What am I doing? Kewin Stoeckigt kstoeckigt@swin.edu.au Centre for Advanced Internet Architectures (CAIA) Swinburne University of Technology Who am I? (The fun facts) I was born...obviously Shoesize: European 41 Amateur photographer Member of the Caulfield Photographic Society Interest in Portrait, Monochromes, Window-Light reflections, patterns Love traveling... working on my second passport Beer drinker...what do you expect, I am German!... Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

2 Who am I? (The serious facts) Education Studied Computer science and Law and the University of Leipzig and the University of Goettingen, Germany BSc in 2002, Thesis: Videokonferenzen aus sicheren Netzen, GWDG Studied Computer science at the University of Auckland, New Zealand MSc in 2005, Thesis: Congestion behavior of multiple TCP streams, University of Auckland Joined Swinburne in 2008 as a PhD candidate Work Siemens ( 4 years) Joint Computing Center of Max-Planck Gesellschaft and the Institute of Plasmaphysics, Garching, Germany ( (2 1/2 thereof overseas)) AARNet (Australian Academic Research and Education Network), Canberra/Melbourne, Australia ( )...and yes, I got to play with the cool dual 10G network Caia Seminar kstoeckigt@swin.edu.au July 24, A few words about my BSc Supervisor: Prof. Dr. O. Hahn, GWDG (= Computing Center of the University of Goettingen) Thesis: Videokonferenzen aus sicheren Netzen Eng.: Videoconferencing from inside protected networks How do we make H.323 videoconferencing work in a NATed/Firewalled environment? H.323 videoconferencing has two main problems: Dynamic port allocation during initial hand-shake 1718, 1719, 1720 TCP used for Gatekeeper discovery and call setup Ports 1024 used for media streams (up to 6 streams per connection), dynamically negotiated during call setup How do you open ports on a firewall beforehand, if you don t know them? NAT unawareness of sub-standards (H.225, H.245, Q.931) Until recently software was NAT unaware, and all packets contained private IP address How do you send a packet to if you are on a different network? Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

3 A few words about my BSc Use of a media proxy Worked as a man-in-the-middle Bascialy terminated the call and established a new call to the outside world Call 1: Inside Media proxy Call 2: Media proxy Outside... or vice versa Software was available, but didn t work properly prone to crash (itself and whole system) Proxy induced delay 0.5s un-useable Update of underlying libraries and parts of the software was necessary System was stable and could be used in a large production level environment (only outlined in thesis, but later shown in work at Max-Planck) Caia Seminar kstoeckigt@swin.edu.au July 24, A few words about my BSc Solution has been widely adopted in the Research and Education sectors ( 30 NRENs, 100+ Universities) NRENs: AARNet, DFN, SWITCH, Internet2, CZNet, FCCN,... Universities: Deakin, UQ, Swinburne (had an interest, not sure if running yet), OSU, Pepperdine, University of Dresden, FU Berlin, University Duisburg-Essen,... I ran 15 workshops around the world on how to setup and maintain the system in a large scale environments Book chapter in Directory Services Middleware for Multimedia Conferencing, J. Gemmill, J. Lynn, on how to use H.350 with the media proxy Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

4 MSc or Dancing of the TCP streams Supervisor: Nevil Brownlee, UoAuckland & Caida Thesis title: Congestion behavior of multiple TCP streams Analysis of TCP synchronization behavior on congested Internet links Using real trace files - Auckland VI and Auckland VIII trace files (see NLANR website for details) How often do we see TCP synchronization and how does it affect other traffic? Unfortunately work not published (yet??) Caia Seminar kstoeckigt@swin.edu.au July 24, MSc or Dancing of the TCP streams Assuming a congested link, and a router using DropTail for packet discard, simulations (ns2) showed that TCP streams start to synchronize Synchronous increase/decrease of the congestion window (number of outstanding bytes) known sawtooth-pattern ( next slide) cwin not included in TCP header other indicators need to be used, eg. IAT, RTT, packet-loss, ECN,... Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

5 MSc or Dancing of the TCP streams Caia Seminar July 24, MSc or Dancing of the TCP streams As cwin is not in TCP header, IAT was used (simulation showed cwin-iat connection) Caia Seminar SEM KS.pdf July 28, kstoeckigt@swin.edu.au July 24,

6 MSc or Dancing of the TCP streams This behavior lead to the SR-algorithm (Sync-Resume algorithm) Analysis of long running concurrent flows Algorithm used the following steps: 1. Filter flows according to flow criteria (p min = 100, t min = 10s) 2. Find concurrent flows if if if (t i0 == t jo ) t in t jm t in t jm (t i0 < t jo ) t in > t j0 (t i0 > t jo ) t i0 > t jm 3. Find close pair of timestamps (t ik t jl ) t thres 4. Check if IAT s of t ik and t jl are peak: ( n i=0 m i,j ++if IAT ik > IAT ) ( m i j=0 && IAT jl > IAT ) j n m Two matrices SRC-matrix: Absolute value of close pairs (IAT s) SRD-matric: SRC in percent (in relation to overall overlapping packets) Caia Seminar kstoeckigt@swin.edu.au July 24, MSc or Dancing of the TCP streams Results Barely any congestion-induced synchronization effects Synchronizing streams have no impact on other traffic Algorithm identified one network attack (unspecified) in the Auckland VIII, 5am trace; Unusual large proportion of packets < 64 bytes and > 128 bytes One very exciting example of two independent streams synchronize ( see plot next slide) One streams is traffic, other is web traffic Flow 1 Flow 2 src address dst address src port dst port average IAT (msec) average packet size (bytes) Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

7 MSc or Dancing of the TCP streams Results Caia Seminar July 24, MSc or Dancing of the TCP streams Results Caia Seminar July 24, SEM KS.pdf July 28,

8 MSc or Dancing of the TCP streams Results Caia Seminar July 24, Working at Max-Planck Located in Garching (just outside of Munich) from 2002 to 2005 (from 2003 onwards as a remote worker from New Zealand) Two interesting projects: Media proxy for MPG and EFDA (based on my BSc work) QoS measurement of video traffic on the DFN backbone Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

9 Working at Max-Planck Media proxy for MPG and EFDA Had a need for H.323 videoconferencing Firewall couldn t be opened in the Computing Center Media proxy was the solution; I had to make sure it worked in a large scale environment Make it as easy a possible Caia Seminar kstoeckigt@swin.edu.au July 24, Working at Max-Planck Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

10 Working at Max-Planck QoS measurement of video traffic on DFN backbone Project partners: MPG, DFN and AWI Researchers and staff started to complain about quality and artefacts in images Software on devices indicated packet loss, whereas the network staff said there is no packet loss on the network Different network connections at MPG in Garching (622MBit/s), MPG in Greifswald (34MBit/s) and AWI in Bremerhaven (34MBit/s) DFN (Videoservice) had a interest and joined (in cooperation with Computing Center at the University of Erlangen) Enable QoS on the network for the media proxies between the locations Measurement software from University of Erlangen used Central time synchronization (Delay in ntp too long) Measured One-Way-Delay, Jitter, Routing and delay variation Measured initially every 30s, but was then changed to 10s Able to analyze each link (hop) on the network (static routes used) Caia Seminar kstoeckigt@swin.edu.au July 24, July 24, Working at Max-Planck Setup (b) Clock (a) Antenna Caia Seminar kstoeckigt@swin.edu.au SEM KS.pdf July 28,

11 Working at Max-Planck Results After 4 weeks of testing we haven t seen any improvements; unsatisfactory and certainly unexpected Packet loss still shown in system, but not on the network...until Comment: We later learned that late arriving packets are also shown as packet loss, which skewed the picture 25/11/ Caia Seminar kstoeckigt@swin.edu.au July 24, My time at AARNet Australian Academic Research and Education Network Connecting Australia s University and CSIRO Links to all major NREN s, eg. Internet2, SINGAren, etc. A Telco, carrier license 61 Staff all over the country Network engineer from 2005 to 2008 Responsible for the VoIP/Video network Project Manager for AARNet s involvement in the Australian ENUM Trial Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

12 My time at AARNet Caia Seminar July 24, My time at AARNet Caia Seminar July 24, SEM KS.pdf July 28,

13 My time at AARNet VoIP/Video network Based on toll-bypass system (VoIP) Available to all Universities and CSIRO Connection to international Video networks Differentiation between on-net and off-net Hosting a variety of services, such as multi-conference bridges for VoIP, Video and mixed conferences ISDN in-dial Virtual numbering using GDS Tested with ENUM Now all done by NVCS (National Videoconferencing Service) Caia Seminar kstoeckigt@swin.edu.au July 24, My time at AARNet ENUM E.164 NUmber Mapping (RFC3761) Standard to map an E.164 number to a NAPTR (Naming Authority Pointer) in the DNS Not limited to VoIP only Convergence of Voice/Video and Data services Not limited to one standard, eg. SIP only Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

14 My time at AARNet Caia Seminar July 24, My time at AARNet Caia Seminar July 24, SEM KS.pdf July 28,

15 My time at AARNet AARNet was involved from day 1 back in 2003; Trial was governed by ACMA (former ACA) Active participant at the AEDG (Australian Enum Discussion Group) First ENUM Registrar when the Trial went live June 2006 Various hurdles to overcome......mainly human hurdles... Trial was partially successful The timing was wrong...in Australia only (...and the US) Europe is fore-runner (Based on that a friend and I started a personal project called nrenum.net, which is a ENUM service for all NREN s. Was well adopted in Europe and has now been taken on as an official service by Terena) Caia Seminar kstoeckigt@swin.edu.au July 24, What am I doing here? Joined CAIA in early 2008 Supervisor: Hai Vu and Philip Branch Working on the capacity modeling, analysis and improvement of VoIP over wireless networks Why is this of interest? How many VoIP calls can be made over wireless networks? Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

16 What am I doing here? G.711, 20ms packetization Service AP Service STA Arrival AP Arrival STA Arrival rate/service rate [packets/slot] Number of VoIP nodes Caia Seminar kstoeckigt@swin.edu.au July 24, What am I doing here? G.729, 10ms packetization Service AP Service STA Arrival AP Arrival STA Arrival rate/service rate [packets/slot] Number of VoIP nodes Caia Seminar kstoeckigt@swin.edu.au July 24, SEM KS.pdf July 28,

17 This slide is empty...the end Caia Seminar July 24, SEM KS.pdf July 28,