1. ECEN5553 Telecom Systems Dr. George Scheets Week 6 Readings: [12a] "The Real Story of Stuxnet" [12b] "Everything You Know About Cyberwar is Wrong" [12c] "How do the FBI and Secret Service Know Your Network is Breeched Before You Do?" [13a] "Can You Trust Your Fridge?" [13b] "Disaster as CryptoWall encrypts US firm's entire server installation" [13c] "ARIN Finally Runs Out of IPv4 Addresses" Exam #1 No later than 28 September (Remote DL) Results to date (90 points) Hi = 81.4, Low = 46.4, Ave = 68.98, σ = 10.63 A > 78, B > 66, C > 57, D > 48 (Tentative) utline 7 October 2015, Lecture 22 (Live) No later than 14 October (Remote DL)

2. Exam #1 n Grading u Lost points? No comments? → Insufficient info provided F Rule of Thumb: "X" point question needs > "X" facts u Lost points? Comments? Your score ≈ % correct n Not happy with your score? Did you… u Start studying at the last minute? u Read assigned articles? u Answer the question asked? u Use the space provided? F Leave the instructor with impression you could've said more n There is plenty of time to Recover u 365 points remain to be claimed

3. Outlines Received due 7 October (local) 14 October (remote) 18 %

4. WAN Design (Link Reduction) n Start with Traffic Matrix n Examine Full Mesh n Consider eliminating lightly used links u Reroute affected traffic n Compare costs at each iteration

5. WAN Connectivity Options n Internet u Routers are packet aware u Datagrams are assigned trunk BW via StatMux F BW required based more so on average input rates u Each packet individually routed F MPLS enabled networks can use Virtual Circuits u Pricing a function of connection size F & Possibly QoS if MPLS and/or DiffServe used

6. Ex) Commodity Internet Corporate Connectivity Local Carriers dedicate bandwidth to our use. ISP provides random Packet Switched StatMux connectivity via datagrams. OKC Detroit NYC ISP Network Router

7. Ex) Commodity Internet Corporate & Internet Connectivity OKC Detroit NYC ISP Network Router 640 Kbps 576 Kbps 448 Kbps From/ToOKCDETNYCISP OKC-1447660 DET88-2850 NYC11234-40 ISP11010090- 310/280 I/O @ OKC → 640 Kbps 194/186 I/O @ NYC → 448 Kbps 278/166 I/O @ DET → 576 Kbps

8. Ex) IP with QoS Corporate & Commodity Internet Connectivity OKC Detroit NYC Internet Service Provider Network MPLS VC, OKC - Detroit MPLS VC, NYC - OKC 768 Kbps Detroit & NYC: No change. OKC: Port Speed must be bumped to relay Detroit ↔ NYC corporate traffic. From/ToOKCDETNYCISP OKC-1447660 DET88-2850 NYC11234-40 ISP11010090- 576 Kbps 448 Kbps

9. Leased Line at OKC ↔ ISP n Outbound u OKC→Det 144 u OKC→NYC 76 u OKC→ISP 60 u Det →NYC 28 u NYC → Det 34 From/ToOKCDETNYCISP OKC-1447660 DET88-2850 NYC11234-40 ISP11010090- n Inbound u Det→OKC 88 u Det→NYC 28 u NYC→OKC 112 u NYC→Det 34 u ISP → OKC 110 Total Outbound = 342 Kbps Total Inbound = 372 Kbps Leased Line Size > 744 Kbps Leased Line = 768 Kbps minimum.

10. Carrier Leased Line Network Carrier reserves BW from pool for our use. Ex) For a 384 Kbps connection, Cross-Connects assign 6 byte sized TDM time slots 8000 times/second = 6*8*8000 = 384 Kbps. Cross-Connect Trunks Leased Line Byte Aware

11. Internet Service Provider Backbone Router Trunks Leased Line ISP Routers assign BW for our use on Random, as needed basis via StatMux & Packet Switching. Packet Aware

12. LAN Internet Service Provider Network Corporate customers might attach via Edge Router & Leased Lines. Router Trunks Leased Line PC WS

13. Internet (Inside the Cloud) n Infinite Buffers u "OK" so long as Average Offered Input Rate < Output Line Speed Internet Router 100 Mbps Trunk ?? 1.54 Mbps Connections P(Access Line is Active) = 10% How many access lines can this switch support? 100 Mbps/154 Kbps = 649 (theoretically)

14. Internet (Inside the Cloud) n Negligible Buffers u OK so long as Instantaneous Offered Input Rate < Output Line Speed 100 Mbps Trunk ?? 1.54 Mbps Connections P(Access Line is Active) = 10% How many access lines can this switch support? With 404 users, 99.99% sure Input Rate < Line Speed Internet Router

15. Bounds on Packet Switch Carrying Capacity 100 Mbps Trunk, 1.54 Mbps Inputs with 154 Kbps average loads LowerUpper 90% 553 649 99% 485 649 99.9% 439 649 99.99% 404 649 LowerUpper 90% 553 649 99% 485 649 99.9% 439 649 99.99% 404 649 Instantaneous Input < Line Speed Where switch could operate Where switch probably operates

16. Queue Size: Correlated vs Uncorrelated Identical Loads (traffic carried/line speed) mean(queue)=135.6 mean(queue)=32.80 Correlated: Long Term Bursts Uncorrelated: Random Input The negligible buffer analysis does not account for long term bursts. Real world switches have finite buffers. Required size to prevent dropped packets depends on length of burst.

17. Carrier Leased Line Network Cross-Connect Trunks Leased Line Byte Aware LAN PC LAN WS Corporate customers might attach via Edge Router & Leased Lines.

18. Leased Lines (TDM) Leased Line Cross-Connect 3 21 3 21 321321 n TDM time slots are moved from input to output n TDM switch is not "packet aware" n Time slots are allocated whether or not there is any traffic on them

19. Circuit Switched connections waste bandwidth for bursty traffic. time traffic NYC to OKC 1.54 Mbps Line Speed 146 Kbps Average Idle Time >> Active Time

20. Leased Lines (Inside the Cloud) n Example Leased Line Cross-Connect 100 Mbps Trunk ?? 1.54 Mbps Connections P(Access Line is Active) = 10% How many access lines can this switch support? 64 (100% input bps < trunk bps)

21. Given 100 Mbps of Bandwidth... n 641.54 Mbps Circuit Switched TDM Customers with 154 Kbps average load & 100% availability n 404 - 6491.54 Mbps Packet Switched StatMux Customers with 154 Kbps average load & 99.99% availability More Bursty Data Traffic can be moved with the Packet Switched StatMux network. 64 x 154 Kbps = 9.856 Mbps 404 x 154 Kbps = 62.22 Mbps

22. Switched Network Carrying Capacities 0% Bursty 100% Bursty 100% Fixed Rate 0% Fixed Rate Offered Load Carrying Capacity Circuit Switch TDM Packet Switch StatMux

23. Network Cost... n Can be spread over 64 Leased Line customers n Can be spread over 404 Internet customers n The Internet Is a Packet Switched StatMux network Largely hauling bursty data traffic Effectively hauling bursty data traffic Inexpensive (compared to a Leased Line)

24. Internet Performance 0% 100% Trunk Offered Load Number of dropped packets Average Delay for delivered packets This type of plot valid for all real world full duplex statistically multiplexed switches: Ethernet, Internet, Frame Relay

25. Internet Performance Effect of priorities 0% 100% Trunk Offered Load Average Delay for low priority packets Average Delay for all delivered packets Average Delay for high priority packets

26. Internet Performance Effect of priorities 0% 100% Trunk Offered Load Number of low priority drops Number of dropped packets Number of high priority drops

27. Internet Backbone Engineering  Option A) Deploy ‘best effort’ Routers Rapidly Deploy Trunk Bandwidth Keep Trunks Lightly Loaded  Delays will be small  Dropped packets will be few  Quality fine for all traffic

28. Backbone Engineering: Option A 0% 100% Number of dropped packets Average Delay for delivered packets Keep Trunks Lightly Loaded

29. Internet Backbone Engineering n Option B) Deploy more complex QoS enabled Routers Deploy fewer, more heavily loaded Trunks Give preferential treatment to interactive Voice/Video n Option A seems to be preferred today

30. Backbone Engineering: Option B High Priority delay at 50% Load = Delay for all traffic at 20% Load 0% 70% Heavier Trunk Load Average Delay for low priority packets Average Delay for all delivered packets Average Delay for high priority packets

31. Frame Relay n ANSI Standard covering OSI Layer 2 n Accessed by Routers n Derived from X.25 Protocol Dumps almost all error checking n Requires fiber on the long haul n Uses Virtual Circuits (VC’s) VC differs from Datagram Path thru network set up in advance Requires Carrier intervention

32. Frame Relay n 1st Commercial Deployment 1990 u WilTel → Worldcom→ bankrupt → Verizon n Cheaper alternative to Leased Lines n Faster alternative to X.25 n Internet a small network in 1990 u Academia u Military u Some commercial traffic F See CUCKOO'S EGG to get a flavor

33. Frame Relay n 7 Application n 6 Presentation n 5 Session TCP n 4 Transport TCP n 3 Network IP n 2 Data Link Frame Relay n 1 Physical

34. Frame Relay n Committed Information Rate (CIR) Is a Quality of Service Guarantee "Guaranteed" minimum Bandwidth Should be set > average traffic during appropriate peak period n Port Connection Speed a.k.a. Port Speed or Burst Speed Bandwidth you can burst to provided network capacity exists. Set = Bit Rate of Access Line

35. Frame Relay Packet Format Data + Padding 3 20 20 up to 8,146 3 IPTCP FR Header FR Trailer Header includes 10 bit Data Link Connection Identifier (DLCI) - Locally Unique (FR ports) Trailer includes 2 byte CRC Sequence that only checks Header I/O decisions based on FR address & look-up table.