n Read: 2.4 n Problems: 2.1, 2.3, Web 4.2 n Design #1 due 8 February (Async DL) u Late = -1 per working day n Quiz #1 u < 11 February (Async Distance Learning) n Corrected quizzes due 13 February (Live) ECEN4533 Data Communications Lecture #13 6 February 2013 Dr. George Scheets

ECEN4533 Data Communications Lecture #148 February 2013 Dr. George Scheets n Problems: Web 4, 5, & 6 n Design #1 due 8 February (Async DL) u Late = -1 per working day n Quiz #1 u < 11 February (Async Distance Learning) \ u Corrected quizzes due 13 February (Live) n Exam #1: 22 February (Live),

Various Protocols n Ethernet u #1 on the wired LAN F Exceptions in some Data Centers u Had plenty of competition 'til mid-90's u Moving into MAN & WAN F LAN frame is encapsulated n Frame Relay u Introduced commercially in 1990 u Has its own Layer 2 Header Format F In early 90's Ethernet, Token Ring, FDDI commonEthernet, Token Ring, FDDI common IP not yet dominant (Novell common)IP not yet dominant (Novell common)

Various Protocols n ATM u Hot protocol in mid 90's u Complex compared to Frame Relay F Meant to haul all types of traffic F 5 Classes of Service u Derided as too Complex by Internet Fanatics F But now Internet is being asked to move everything F Internet becoming more complex

Various Protocols n Internet u Hot protocol in 2000's u Commodity Internet F Treats all traffic the same u Corporate Internet F Becoming more complex DiffServ: Enables Priorities Not Used on Commodity InternetDiffServ: Enables Priorities Not Used on Commodity Internet Multi-Protocol Label Switching Enables Virtual CircuitsMulti-Protocol Label Switching Enables Virtual Circuits

Internet Traffic Growth source: "The Road to 100G Deployment", IEEE Communications Magazine, March 2010

Internet Traffic Comparison source:

2011 Internet Traffic Profile Source: Global Internet Phenomena Report.pdf

2011 Internet Traffic Profile Source: Global Internet Phenomena Report.pdf

ISP Router Overload Source: 1 October 2007 Network World Fall 2011 Level3 BGP entries 375,550 IPv4 7,210 IPv6 Peak Traffic 8.0 Tbps IPv4 500 Mbps IPv6

Router n Operates at OSI Layers 1-3 n Communicate with adjacent Routers u Exchange "Hello" packets every 10 or so seconds u Exchange Routing info F immediately upon "Hello" failure F general updates several times a day independent of traffic n Use Routing info to generate a Hierarchical Routing Table Example) ISP Backbone Routers Must know how to get to ibm.ucc.okstate.edu Example) OSU Campus Backbone Routers Must know how to get to ibm.ucc.okstate.edu

Switched Ethernet Trunks Access Lines PC Switched Hub Switched Hub Switched Hub PC Pr R Switched Hub Packet formatting same as before. Only the Printer will see packets from the PC.

Switched Ethernet Trunks Access Lines PC Packets need to cross a network boundary. Switched Hub Switched Hub PC Pr R Switched Hub

Ex) Leased Lines OKC Detroit NYC Carrier Leased Line Network Router From/ToOKCDETNYC OKC DET88-28 NYC Kbps 128 Kbps 256 Kbps Traffic Matrix (Bursty Data) Suppose: *BW available in 64 Kbps chunks (64, 128, 192, 256, 320, 384, 448, etc.) *Maximum load (traffic/BW) = 50%

Ex) Leased Lines OKC Detroit NYC Carrier Leased Line Network Router 384 Kbps From/ToOKCDETNYC OKC DET88-28 NYC Kbps Suppose: *BW available in 64 Kbps chunks (64, 128, 192, 256, 320, 384, 448, etc.) *Maximum load (traffic/BW) = 50%

OKC Detroit NYC Carrier Leased Line Network Router 576 Kbps ISP 448 Kbps Ex) Leased Lines with Internet thru OKC From/ToOKCDETNYCISP OKC DET NYC ISP Kbps

Ex) Commodity Internet Corporate Connectivity OKC Detroit NYC ISP Network Router 448 Kbps 384 Kbps 320 Kbps From/ToOKCDETNYC OKC DET88-28 NYC11234-

Ex) Commodity Internet Corporate & Internet Connectivity OKC Detroit NYC ISP Network Router 640 Kbps 576 Kbps 448 Kbps From/ToOKCDETNYCISP OKC DET NYC ISP /280 OKC → 640 Kbps 194/186 NYC → 448 Kbps 278/166 DET → 576 Kbps

LAN PC LAN PC Virtual Circuit Backbone VC Switch VC #2 Suppose we need to connect to three LAN's. LAN Server VC #1

Ex) Frame Relay, ATM, MPLS, Carrier Ethernet Corporate Connectivity OKC Detroit NYC Carrier Frame Relay, ATM, Ethernet, or MPLS Internet Network. PVC, OKC - Detroit PVC, NYC - OKC 576 Kbps 384 Kbps 320 Kbps From/ToOKCDETNYC OKC DET88-28 NYC OKC Outbound = Kbps OKC Inbound = Kbps Leased Line Size > 2*282 = 564 Kbps Leased Line = 576 Kbps minimum.

OKC Detroit NYC Carrier Ethernet, ATM, MPLS, or FR Network Resized PVC, OKC - Detroit Resized PVC, NYC - OKC Router ISP Ex) Carrier Ethernet, FR, ATM, MPLS Corporate & Internet Connectivity From/ToOKCDETNYCISP OKC DET NYC ISP Kbps 576 Kbps 448 Kbps OKC FR Leased Line must handle NYC & Det traffic ↔ Internet, OKC ↔ corporate, and Detroit/NYC pass-thru traffic. 960 Kbps

Leased Line at OKC ↔ FR Net n Outbound u OKC→Det 144 u OKC→NYC 76 u Det→NYC 28 u NYC→Det 34 u ISP→Det 100 u ISP→NYC 90 From/ToOKCDETNYCISP OKC DET NYC ISP n Inbound u Det→OKC 88 u Det→NYC 28 u Det→ISP 50 u NYC→OKC 112 u NYC→Det 34 u NYC→ISP 40 Total Outbound = 472 Kbps Total Inbound = 352 Kbps Leased Line Size > 944 Kbps Leased Line = 960 Kbps minimum. OKC ISP Detroit NYC

Circuit Switched TDM Leased Line Cross-Connect 100 Mbps Trunk ?? 1.54 Mbps Connections P(Access Line is Active) = 10% Trunk Bandwidth is assigned based on peak input rates. Can support 64 access lines.

Queue Length n 100,000,000 bps output trunk n 100,000,001 bps average input n Average Input rate > Output rate n Queue Length builds up (without bound, in theory)

Queue Length n 100,000,000 bps output trunk n 99,999,999 bps average input n Average Input rate < Output rate n Queue Length not infinite......but very large

Queue 100% Load Output capacity = 7 units Input = 7 units on average (two dice rolled) n t1: input = 4, output = 4, queue = 0 n t2: input = 5, output = 5, queue = 0 n t3: input = 4, output = 4, queue = 0 n t4: input = 7, output = 7, queue = 0 n t5: input = 11, output = 7, queue = 4 n t6: input = 10, output = 7, queue = 7 n t7: input = 6, output = 7, queue = 6 n t8: input = 5, output = 7, queue = 4 n t9: input = 8, output = 7, queue = 5 n t10: input = 11, output = 7, queue = 9 This queue will tend to get very large over time.

Queue Load Will tend to increase w/o Bound.

Packet Switched StatMux Router or Switch 100 Mbps Trunk ?? 1.54 Mbps Connections P(Access Line is Active) = 10% Trunk Bandwidth assigned based on average input rates. Can theoretically support 649 access lines. Note if all inputs active, input = Mbps

Probability Density Functions n A Histogram is an estimate of the PDF n Important PDF's for Networking u Gaussian F Very common in the Real World u Binomial F Individual Experiment has 2 states F Experiment results are Independent F Interested in # of successful experiments, not specific order u Exponential F Not a bad model for packet sizes u Poisson

1995 OSU Backbone Packet Histogram Looks somewhat exponential.

2004 OSU Backbone Packet Histogram Still looks sort of exponential, but less so than before,

IM Traffic Message Size

Traffic in 0.1 second intervals