ECEN5553 Telecom Systems Dr. George Scheets ECEN5553 Telecom Systems Dr. George Scheets Week #5 Homework: Read [7] "Cybercrime: Dissecting the State of Underground Enterprise" Exam #1: Lecture 14, 16 September (Live) No later than 23 September (Remote DL) 4 page test. Work 3. 1-2 pages will be off Fall 2015 Exam #1 Outline: Lecture 22, 5 October (Live) No later than 12 October (Remote DL)

Outlines Received due 5 October (local) 12 October (remote) 10 %

Exam #1 (90 points) Friday, 16 September (Local) Remote Distant Learners, no later than 23 September Work 3 of 4 pages Closed Book & Notes Calculators & phones are NOT allowed ...Set up numerical problem for full credit Most equations are provided (on 5th page) Approximately 40% of upcoming exam will be lifted from the Fall 2015 Exam #1 Anything in the notes, on Power Point, or in reading assignments is fair game

On Short Answer or Essay Questions Answer the Question! Memory Dump in the space provided Knowledgeable individual can write more To get "A" or "B", instructor needs to walk away with impression you could've said more Got space? Anything else pertinent to add? Rule of Thumb: "X" point question needs > "X" facts It is NOT necessary to write small or fill up allotted space to get a good score!

OSU Backbone Trunks Access Line Router Access lines attach to switches and other routers. Highest internal trunk speeds now 40 & 100 Gbps.

ISO OSI Seven Layer Model Layer 7 Application Layer 6 Presentation Windows API Layer 5 Session Windows TCP Layer 4 Transport Windows TCP Layer 3 Network Windows IP Layer 2 Data Link PC NIC Layer 1 Physical PC NIC

Internet Protocal v4 (20 Bytes) TOS TTL Source Address Destination Address

Microsoft's Tracert

802.3 Ethernet Packet Format Bytes: 7 1 6 6 2 MAC Destination Address MAC Source Address 20 20 6-1460 4 IPv4 TCP Data + Padding CRC

IPv4 Header Contains two addresses Example address 4B Source Address 4B Destination Address 4B = 32b = 4.295 G potential addresses Example address 10001011 01001110 01000010 11010011 Dotted Decimal Format simplifies x.x.x.x Treat each byte as Base2 number, write in Base10 Above number simplifies to 139.78.66.211

IP Header Alpha-numeric name simplifies further es302.ceat.okstate.edu Domain Name Servers convert to numerical All OSU Stillwater addresses are of form 139.78.0.0 to 139.78.255.255 IP addresses & alpha-numeric names are effectively backwards 139.78.66.211 mapped to es302.ceat.okstate.edu

IP vs Ethernet Addresses Ethernet has a flat address space Similar to Social Security Number Adjacent #'s nearby or on other side of globe? Huge look up tables required to avoid flooding Need 70.37 trillion entries IP has a hierarchical address space Packet delivery similar to Mail delivery Adjacent IP addresses frequently nearby Reduces size of look up tables Don't need 4.295 billion entries

ISP Router Overload Fall 2011 Level3 BGP entries 375,550 IPv4 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

ISP Router Overload Core BGP entries as of 19 August 2014 IPv4 about 520,400 IPv6 about 18,300 2nd week of August Caused some problems Some routers had 512,000 entry limit source: bgp.potaroo.net Network World , 13Aug2014, "Internet outages expected to abate as routers are modified, rebooted"

ISP BGP Table source: http://bgp.potaroo.net/index-bgp.html

TCP Header 4 Bytes Source Port Destination Port Sequence Number ACK Number Window Checksum

Wireshark Packet Capture This interaction started with a click on a Firefox bookmark (for a distance calculator) on a computer in Engineering South at OSU Stillwater. Firefox then triggers a query to an OSU Domain Name Server asking for the IPv4 address of www.indo.com. This is next followed by a TCP 3 way handshake to open logical connections, an HTTP request to download the distance calculator page, and the beginning of the file transfer.

ISO OSI Seven Layer Model MSS = 1460 B = Size of Layer 6 & 7 info per packet Layer 7 Application Layer 6 Presentation Windows API Layer 5 Session Windows TCP Layer 4 Transport Windows TCP Layer 3 Network Windows IP Layer 2 Data Link PC NIC Layer 1 Physical PC NIC Ethernet Payload = 1500 B

TCP Window Size (Layer 4) Effects End-to-End Throughput Suppose Window Size (set by PC) = 64 KB Microsoft Windows XP Maximum Segment Size = 1 KB Server can send < 64 unACK'd packets Server PC 3,000 Km

Throughput on 64 Kbps Line Server PC Packet #1 3,000 Km, 64 Kbps line NPD = Prop Delay / Packet inject time Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds Packet inject time = 8,376 bits / 64 Kbits/sec = 0.1309 seconds (7B PPP, 20B IPv4, 20B TCP) NPD = 0.015 / 0.1309 = 0.1146 Front end of packet arrives at far side prior to back end being transmitted.

Throughput on 64 Kbps Line Server PC Packet #2 #1 #1 ACK 3,000 Km, 64 Kbps line At this instant in time... 2nd unACK'd packet is being transmitted ACK for #1 enroute back to server TCP+IP+Layer 2 → 47 bytes if PPP When ACK#1 arrives at server, only packet #2 is unacknowledged. Will 64 packet unACK'd limit be reached? No. At most, 1 packet likely unACK'd.

Throughput on 45 Mbps Line Server PC #3 #2 #1 3,000 Km, 45 Mbps line NPD = Prop Delay / Packet inject time Prop Delay = distance / EM energy speed = 3,000,000 m / 200,000,000 m/sec = 0.015 seconds Packet inject time = 8,376 bits / 45 Mbits/sec = 186.1 μseconds (PPP, IPv4, TCP overhead) NPD = 0.015 / 0.0001861 = 80.60 80.60 average sized packets will fit back-to-back on this line

Throughput on 45 Mbps Line Server PC Packets 1 - 64 3,000 Km, 45 Mbps line At this instant in time, the Server... Has transmitted 64 packets w/o ACK. Has hit window limit. Halts.

Throughput on 45 Mbps Line Server PC Packets 2 - 64 #1 ACK#1 3,000 Km, 45 Mbps line At this instant in time, The PC has processed 1st packet & sent an ACK The Server is still halted, waiting for ACK #1. When ACK #1 arrives, server can then transmit one additional packet. Other ACK’s arrive fast enough to allow back-to-back transmission of next group of 64 packets

Can Estimate Throughput with a Time Line to = 0 t1 t2 t3 time to: Leading edge of 1st packet injected t1: Trailing edge of 64th packet injected t1 = (64*1047B)(8b/B)/(45 Mb/sec) = 11.91 msec t2: Leading edge of 1st packet hits far side 15 msec (propagation delay) If ACK injected right away... t3: ...ACK arrives at server at t = 30 msec Process Repeats...

Can Estimate Throughput with a Time Line to = 0 11.91 15.00 30.00 time (msec) This system can transmit 64(1,047) = 67,008 B = 536,064 bits Every 30 msec (one round trip time) Estimated throughput = 536,064/0.03 = 17.89 Mbps Actual throughput a bit lower 1st ACK not transmitted until packet #1 fully received... ... and processed by PC 65th packet not transmitted until ACK #1 fully received... ... and processed by Server

Can Estimate Throughput with a Time Line to = 0 11.91 15.00 30.00 time (msec) Need to be able to fill the pipe for 1 RTT 30 msec in our example 45 Mbps * .030 sec = 1.35 M b = 168,750 B = 168,750/1,047 = 161.2 packets Window Size needs to be = 161.2 segments*1,000 bytes/segment = 161,200 B Actually would need another segment or two to cover source & sink processing

UDP Header (8 Bytes) 4 Bytes Source Port Destination Port Checksum For interactive real-time traffic, usually used with Real Time Transport Protocol (12 bytes).

Virtual Circuits Routing decisions made once when circuit is set up Concerned switches have internal Look-Up tables updated All packets part of info transfer follow the same path Allows option of setting aside switch resources (buffer space, bandwidth) for specific traffic flows MPLS, Frame Relay, ATM, & Carrier Ethernet use VC’s

Datagrams IP uses Datagrams Routing Tables updated independently of individual traffic flows Routers continuously talking with each other Packets may follow different paths Routers get no advance warning of specific packet flows.

IP is Connectionless 20 20 up to 1,460 IP TCP Data + Padding I/O decisions based on IP address & look-up table. Tables updated independent of traffic, hence path thru network may suddenly change. TCP is connection oriented.

TCP, UDP, and IP 30+ year old Protocols Designed for data One Utilized Priority & “Best Effort” services No QoS Guarantees Available bandwidth depends on other users TCP (Layer 4 & 5) provides reliable transfer UDP (Layer 4 & 5) unreliable transfer IP at Layer 3 Arbitrary Protocols at Layers 1 & 2

Internet Traffic 2008 - 2009 Comparison source: http://www.sandvine.coms

Fixed Access Internet Traffic Profile 2013 Source: www.sandvine.com/downloads/documents/Phenomena_2H_2012/ Sandvine_Global_Internet_Phenomena_Snapshot_2H_2012_NA_Fixed.pdf & www.sandvine.com/downloads/general/global-internet-phenomena/2014/1h-2014-global-internet-phenomena-report.pdf

2016 Fixed Access https://www.sandvine.com/downloads/general/global-internet-phenomena/2016/global-internet-phenomena-report-latin-america-and-north-america.pdf

2012 Mobile Access Internet Traffic Profile http://www.sandvine.com/downloads/documents/Phenomena_2H_2012/ Sandvine_Global_Internet_Phenomena_Snapshot_2H_2012_NA_Mobile.pdf

2016 Mobile Access https://www.sandvine.com/downloads/general/global-internet-phenomena/2016/global-internet-phenomena-report-latin-america-and-north-america.pdf

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

Internet Traffic Growth source: www.cisco.com/c/en/us/solutions/collateral/service-provider/visual-networking-index-vni/VNI_Hyperconnectivity_WP.html

Combining the Figures

VoIP PC to PC Internet Phone to Internet Phone Commodity Internet

VoIP PC to Wired Phone Internet Phone to Wired Phone Gateway Commodity System

VoIP (Wired Phone-to-Wired Phone) Carrier prioritizes VoIP traffic (DiffServ) Paths nailed down (MPLS) Gateways control # of voice calls Good Quality Possible with this configuration Gateway Gateway Phone System Phone System "QoS Enabled" Internet