DOC PREVIEW
Berkeley COMPSCI 252 - Lecture 9: Network 2: Protocols, Routing, Wireless

This preview shows page 1-2-3-19-20-39-40-41 out of 41 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 41 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

CS252 Graduate Computer Architecture Lecture 9: Network 2: Protocols, Routing, WirelessReview: Network BasicsReview: Performance MetricsReview: InterconnectionsCompare MediaInterconnect IssuesConnecting Multiple ComputersConnection-Based vs. ConnectionlessSlide 9Routing MessagesDeterministic Routing ExamplesStore and Forward vs. Cut-ThroughCut-Through vs. Store and ForwardCongestion ControlProtocols: HW/SW InterfaceCS 252 AdministriviaNetwork/Routers Berkeley/StanfordNetwork/Routers Berkeley/Stanford IITraceRoute Berkeley to Stanford, I (round trip times for 3 probes)TraceRoute Berkeley to Stanford, IIProtocol Family ConceptSlide 22TCP/IP packet, Ethernet packet, protocolsExample NetworksConnecting NetworksComparing NetworksSlide 27Slide 28Packet FormatsWireless NetworksIssues in WirelessReliability of Wires Transmission2 Wireless ArchitecturesCellular TelephonyCellular Telephony IIPractical Issues for Inteconnection NetworksSlide 37Practical IssuesCross-Cutting Issues for NetworkingCrosscutting: Smart Switch vs. Smart Network Interface CardSummary: NetworkingCS252/PattersonLec 9.12/14/01CS252Graduate Computer ArchitectureLecture 9: Network 2: Protocols, Routing, WirelessFebruary 14, 2001Prof. David A. PattersonComputer Science 252Spring 2001CS252/PattersonLec 9.22/14/01Review: Network Basics•Link made of some physical media–wire, fiber, air•with a transmitter (tx) on one end–converts digital symbols to analog signals and drives them down the link•and a receiver (rx) on the other–captures analog signals and converts them back to digital signals•tx+rx called a transceiver01100110CS252/PattersonLec 9.32/14/01Review: Performance MetricsSenderReceiverSenderOverheadTransmission time(size ÷ bandwidth)Transmission time(size ÷ bandwidth)Time ofFlightReceiverOverheadTransport LatencyTotal Latency = Sender Overhead + Time of Flight + Message Size ÷ BW + Receiver OverheadTotal Latency(processorbusy)(processorbusy)Includes header/trailer in BW calculation?CS252/PattersonLec 9.42/14/01Review: Interconnections•Communication between computers•Packets for standards, protocols to cover normal and abnormal events•Performance issues: HW & SW overhead, interconnect latency, bisection BW•Media sets cost, distanceCS252/PattersonLec 9.52/14/01Compare Media•Assume 40 2.5" disks @ 25 GB (1 TB), Move 1 km•Compare Cat 5 (100 Mbit/s), Multimode fiber (1000 Mbit/s), single mode (5000 Mbit/s), and car•Cat 5: 1000 x 1024 x 8 Mb / 100 Mb/s = 23 hrs•MM: 1000 x 1024 x 8 Mb / 1000 Mb/s = 2.3 hrs•SM: 1000 x 1024 x 8 Mb / 5000 Mb/s = 0.5 hrs•Car: 5 min + 1 km / 50 kph + 10 min = 0.25 hrs•Car of disks = high BW mediaCS252/PattersonLec 9.62/14/01Interconnect Issues•Performance Measures•Network Media•Connecting Multiple ComputersCS252/PattersonLec 9.72/14/01Connecting Multiple Computers•Shared Media vs. Switched: pairs communicate at same time: “point-to-point” connections•Aggregate BW in switched network is many times shared–point-to-point faster since no arbitration, simpler interface•Arbitration in Shared network?–Central arbiter for LAN?–Listen to check if being used (“Carrier Sensing”)–Listen to check if collision (“Collision Detection”)–Random resend to avoid repeated collisions; not fair arbitration; –OK if low utilization(A. K. A. data switching interchanges, multistageinterconnection networks,interface message processors)CS252/PattersonLec 9.82/14/01Connection-Based vs. Connectionless•Telephone: operator sets up connection between the caller and the receiver–Once the connection is established, conversation can continue for hours•Share transmission lines over long distances by using switches to multiplex several conversations on the same lines–“Time division multiplexing” divide B/W transmission line into a fixed number of slots, with each slot assigned to a conversation•Problem: lines busy based on number of conversations, not amount of information sent•Advantage: reserved bandwidthCS252/PattersonLec 9.92/14/01Connection-Based vs. Connectionless•Connectionless: every package of information must have an address => packets –Each package is routed to its destination by looking at its address–Analogy, the postal system (sending a letter)–also called “Statistical multiplexing”–Note: “Split phase buses” are sending packetsCS252/PattersonLec 9.102/14/01Routing Messages•Shared Media–Broadcast to everyone•Switched Media needs real routing. Options:–Source-based routing: message specifies path to the destination (changes of direction)–Virtual Circuit: circuit established from source to destination, message picks the circuit to follow–Destination-based routing: message specifies destination, switch must pick the path»deterministic: always follow same path»adaptive: pick different paths to avoid congestion, failures»Randomized routing: pick between several good paths to balance network loadCS252/PattersonLec 9.112/14/01•mesh: dimension-order routing–(x1, y1) -> (x2, y2)–first x = x2 - x1,–then y = y2 - y1,•hypercube: edge-cube routing–X = xox1x2 . . .xn -> Y = yoy1y2 . . .yn–R = X xor Y–Traverse dimensions of differing address in order•tree: common ancestor•Deadlock free?Deterministic Routing Examples001000101100010110111011CS252/PattersonLec 9.122/14/01Store and Forward vs. Cut-Through•Store-and-forward policy: each switch waits for the full packet to arrive in switch before sending to the next switch (good for WAN)•Cut-through routing or worm hole routing: switch examines the header, decides where to send the message, and then starts forwarding it immediately –In worm hole routing, when head of message is blocked, message stays strung out over the network, potentially blocking other messages (needs only buffer the piece of the packet that is sent between switches). –Cut through routing lets the tail continue when head is blocked, accordioning the whole message into a single switch. (Requires a buffer large enough to hold the largest packet).CS252/PattersonLec 9.132/14/01Cut-Through vs. Store and Forward•Advantage–Latency reduces from function of:number of intermediate switches X by the size of the packet to time for 1st part of the packet to negotiate the switches + the packet size ÷ interconnect BWCS252/PattersonLec 9.142/14/01Congestion Control•Packet switched networks do not reserve bandwidth; this leads to contention (connection based limits


View Full Document

Berkeley COMPSCI 252 - Lecture 9: Network 2: Protocols, Routing, Wireless

Documents in this Course
Quiz

Quiz

9 pages

Caches I

Caches I

46 pages

Lecture 6

Lecture 6

36 pages

Lecture 9

Lecture 9

52 pages

Figures

Figures

26 pages

Midterm

Midterm

15 pages

Midterm

Midterm

14 pages

Midterm I

Midterm I

15 pages

ECHO

ECHO

25 pages

Quiz  1

Quiz 1

12 pages

Load more
Download Lecture 9: Network 2: Protocols, Routing, Wireless
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Lecture 9: Network 2: Protocols, Routing, Wireless and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Lecture 9: Network 2: Protocols, Routing, Wireless 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?