Announcements. CS 5565 Network Architecture and Protocols. Ethernet. Ethernet. Ethernet Model. Ideal Multiple Access Protocol

Size: px
Start display at page:

Download "Announcements. CS 5565 Network Architecture and Protocols. Ethernet. Ethernet. Ethernet Model. Ideal Multiple Access Protocol"

Transcription

1 nnouncements CS 5565 Network rchitecture and Protocols Lecture 4 odmar ack Project due in parts: pr 5 and May xtra Credit Opportunities: xpand simulator (and your implementation) to introduce multiple link failures and link resurrection thernet thernet dominant wired LN technology: cheap <$0 for 00Mbps! first widely used LN technology standardized in 80.3 series of I standards simpler, cheaper than token LNs and TM kept up with speed race: 0 Mbps 0 bps Metcalfe s thernet sketch 4 thernet Model Connectionless: No handshaking between sending and receiving adapter Unreliable: No acks (or nacks) higher-level protocols must compensate, but low R (bit error rate) CSM/CD: no slots random access protocol 5 Ideal Multiple ccess Protocol roadcast channel of rate R bps. When one node wants to transmit, it can send at rate R.. When M nodes want to transmit, each can send at average rate R/M 3. Fully decentralized: no special node to coordinate transmissions no synchronization of clocks, slots 4. Simple 6

2 MC Protocols: a taxonomy MC Media ccess Control Three broad classes: Channel Partitioning divide channel into smaller pieces (time slots, frequency, code) allocate piece to node for exclusive use Random ccess channel not divided, allow collisions recover from collisions Taking turns Nodes take turns, but nodes with more to send can take longer turns Star Topology us topology popular through mid 90s Now star topology prevails Connection choices: or Hubs rarely used nowadays or 7 8 thernet Frame Structure Sending adapter encapsulates IP datagram (or other network layer protocol packet) in thernet frame <05DC 80.3 Length 0800 IP 0806 RP 809 ppletalk Preamble: 7 bytes with pattern 0000 followed by one byte with pattern 000 used to synchronize receiver, sender clock rates 9 thernet CSM/CD algorithm. daptor receives datagram from net layer & creates frame. If adapter senses channel idle, it starts to transmit frame. If it senses channel busy, waits until channel idle and then transmits 3. If adapter transmits entire frame without detecting another transmission, the adapter is done with frame! 4. If adapter detects another transmission while transmitting, aborts and sends jam signal 5. fter aborting, adapter enters exponential backoff: after the mth collision, adapter chooses a K at random from {0,,,, m -}. dapter waits K 5 bit times and returns to Step 0 thernet s CSM/CD (more) Jam Signal: make sure all other transmitters are aware of collision; 48 bits it time:. microsec for 0 Mbps thernet ; for K=03, wait time is about 50 msec See/interact with Java applet on WL Web site: highly recommended! xponential ackoff: oal: adapt retransmission attempts to estimated current load heavy load: random wait will be longer first collision: choose K from {0,}; delay is K 5 bit transmission times after second collision: choose K from {0,,,3} after ten collisions, choose K from {0,,,3,4,,03} CSM/CD efficiency t prop = max prop between nodes in LN t trans = time to transmit max-size frame efficiency 5t / prop t trans fficiency goes to as t prop goes to 0 oes to as t trans goes to infinity Much better than LOH, but still decentralized, simple, and cheap

3 fficiency of 0Mbps thernet thernet Physical Layer ackoff slot times is 5-bit N: does not imply CSM/CD thernet is slotted 3 4 Manchester ncoding Used in 0aseT ach bit has a transition llows clocks in sending and receiving nodes to synchronize with each other no need for a centralized, global clock among nodes! 5 Fast thernet: 00aseT 45 it ncoding MLT-3 (Multi-Level Threshold) Source: igabit thernet uses standard thernet frame format allows for point-to-point links and shared broadcast channels in shared mode, CSM/CD is used; short distances between nodes required for efficiency supports s, called here uffered Distributors Though you wouldn t use them full-duplex at bps for point-to-point links 000aseT: 80 coding with 5 signal levels See IOL page for more information Hubs Hubs are essentially physical-layer repeaters: bits coming from one link go out all other links at the same rate no frame buffering no CSM/CD at : adapters detect collisions provides net management functionality Single collision domain 7 8 3

4 Interconnecting LNs Hypothetical design: backbone interconnects LN segments Disadvantage: individual segment collision domains become one large collision domain can t interconnect 0aseT & 00aseT Switches Link layer device stores and forwards thernet frames examines frame header and selectively forwards frame based on MC dest address when frame is to be forwarded on segment, uses CSM/CD to access segment transparent hosts are unaware of presence of es plug-and-play, self-learning es do not need to be configured 9 0 Forwarding 3 How do determine onto which LN segment to forward frame? Looks like a routing problem... N: Switches are called bridges if #interfaces == has a table Self Learning entry in table: (MC ddress, Interface, Time Stamp) stale entries in table dropped (TTL can be 60 min) learns which hosts can be reached through which interface when frame received, learns location of sender: incoming LN segment records sender/location pair in table Switch xample Suppose C sends frame to D Switch xample () Suppose D replies back with frame to C. 3 address interface I D F C H Switch receives frame from C notes in bridge table that C is on interface because D is not in table, forwards frame into interfaces and 3 frame received by D 3 3 C D Switch receives frame from from D notes in bridge table that D is on interface because C is in table, forwards frame only to interface frame received by C F 4 H address interface I C 3 4

5 Switch: Traffic Isolation installation breaks subnet into LN segments filters packets: same-ln-segment frames not usually forwarded onto other LN segments segments become separate collision domains Nowadays: direct to host connection -> no collisions! collision domain collision domain collision domain 5 Switches: Dedicated ccess Switch with many interfaces Hosts have direct connection to No collisions; full duplex -to- and -to-f simultaneously cut-through ing: frame forwarded from input to output port without first collecting entire frame slight reduction in latency C F 6 D This is the dominant technology today Switches: Flow Control What if =00Mbps, =0Mbps? host sends frames faster than can send them out of outgoing port undetected losses due to overflow could occur I 80.3 provides LLC layer that has flow control facilities pause frames to get sender to stop to external network Switches vs Routers router mail server web server IP subnet 7 8 Spanning Tree ridges Switches self-configure into spanning tree 9 80.D ased on [Perlman 985] Spanning Tree algorithm Root selection by lowest MC ID Link-State approach: HLLO messages Links are in states: CKUP (inactive) or FORWRDIN (active) and in-between states reaks loops fast, recovery takes up to min Disadvantage: Slow convergence after breakage 80.w: RSTP (Rapid STP) Lack of multipath capability Not aware of VLNs (discussed next) 30 5

6 Virtual LNs Virtual LNs () (a) Four physical LNs organized into two VLNs, gray and white, by two bridges. (b) The same 5 machines organized into two VLNs by es. 3 3 The I 80.Q Standard Transition from legacy thernet to VLNaware thernet. The shaded symbols are VLN aware. The empty ones are not. The I 80.Q Standard () 80.Q thernet frame format VLN ssociation may be done Via port Via MC address Via Layer 3 information (IP address) Switches vs. Routers both store-and-forward devices routers: network layer devices (examine network layer headers) es are link layer devices routers maintain routing tables, implement routing algorithms es maintain tables, implement filtering, learning algorithms + spanning tree algorithms Hubs vs. Routers vs. Switches Traffic isolation Hubs Routers Switches No Yes Yes Plug & Play Yes No Yes Optimal Routing Cut Through No Yes No Yes No Yes

Chapter 5: The Data Link Layer. Chapter 5 Link Layer and LANs. Ethernet. Link Layer. Star topology. Ethernet Frame Structure.

Chapter 5: The Data Link Layer. Chapter 5 Link Layer and LANs. Ethernet. Link Layer. Star topology. Ethernet Frame Structure. hapter 5 Link Layer and LNs omputer Networking: Top Down pproach 5 th edition. Jim Kurose, Keith Ross ddison-wesley, pril 2009. hapter 5: The Data Link Layer Our goals: understand principles behind data

More information

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols Link Layer: Introduction daptors ommunicating Terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless links LNs

More information

Review. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD

Review. Error Detection: CRC Multiple access protocols. LAN addresses and ARP Ethernet. Slotted ALOHA CSMA/CD Review Error Detection: CRC Multiple access protocols Slotted ALOHA CSMA/CD LAN addresses and ARP Ethernet Some slides are in courtesy of J. Kurose and K. Ross Overview Ethernet Hubs, bridges, and switches

More information

CSC 4900 Computer Networks: Link Layer (2)

CSC 4900 Computer Networks: Link Layer (2) CSC 4900 Computer Networks: Link Layer (2) Professor Henry Carter Fall 2017 Link Layer 6.1 Introduction and services 6.2 Error detection and correction 6.3 Multiple access protocols 6.4 LANs addressing,

More information

Links. Error Detection. Link Layer. Multiple access protocols. Nodes Links Frame. Shared channel Problem: collisions How nodes share a channel

Links. Error Detection. Link Layer. Multiple access protocols. Nodes Links Frame. Shared channel Problem: collisions How nodes share a channel Link Layer Error Detection Nodes Links Frame R yclic Redundancy hecksum Parity its More about this in exercise! Data Link Layer -1 Data Link Layer -2 Links Two types of links : point-to-point broadcast

More information

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols

Adaptors Communicating. Link Layer: Introduction. Parity Checking. Error Detection. Multiple Access Links and Protocols Link Layer: Introduction daptors ommunicating hosts and routers are nodes links connect nodes wired links wireless links layer-2 packet is a frame, encapsulates datagram datagram controller sending host

More information

The Link Layer and LANs: Ethernet and Swiches

The Link Layer and LANs: Ethernet and Swiches The Link Layer and LNs: Ethernet and Swiches EECS3214 2018-03-21 Link layer, LNs: outline 6.1 introduction, services 6.2 error detection, correction 6.3 multiple access protocols 6.4 LNs addressing, RP

More information

Principles behind data link layer services

Principles behind data link layer services Data link layer Goals: Principles behind data link layer services Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control: Done!

More information

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services Chapter 5 Link Layer & LNS Link Layer: Introduction Some terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless

More information

Link Layer and LANs. Our Goals. Link Layer

Link Layer and LANs. Our Goals. Link Layer Link Layer and LANs Instructor: Anirban Mahanti Office: ICT 745 Email: mahanti@cpsc.ucalgary.ca Class Location: ICT 121 Lectures: MWF 12:00 12:50 hours Notes derived from Computer Networking: A Top Down

More information

Data Link Layer. Our goals: understand principles behind data link layer services: instantiation and implementation of various link layer technologies

Data Link Layer. Our goals: understand principles behind data link layer services: instantiation and implementation of various link layer technologies Data Link Layer Our goals: understand principles behind data link layer services: link layer addressing instantiation and implementation of various link layer technologies 1 Outline Introduction and services

More information

Hubs. twisted pair. hub. 5: DataLink Layer 5-1

Hubs. twisted pair. hub. 5: DataLink Layer 5-1 Hubs Hubs are essentially physical-layer repeaters: bits coming from one link go out all other links at the same rate no frame buffering no CSMA/CD at : adapters detect collisions provides net management

More information

Lecture 9 The Data Link Layer part II. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 9 The Data Link Layer part II. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 9 The Data Link Layer part II Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Physical Addresses Physical (or LAN or MAC) address: 48 bit string Hexadecimal representation

More information

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services Chapter 5 Link Layer & LNS Link Layer: Introduction Some terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless

More information

Lecture 5 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 5 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 5 The Data Link Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Link Layer: setting the context two physically connected devices: host-router, router-router, host-host,

More information

Principles behind data link layer services:

Principles behind data link layer services: Data link layer Goals: Principles behind data link layer services: Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control Example

More information

Principles behind data link layer services:

Principles behind data link layer services: Data link layer Goals: Principles behind data link layer services: Error detection, correction Sharing a broadcast channel: Multiple access Link layer addressing Reliable data transfer, flow control Example

More information

Summary of MAC protocols

Summary of MAC protocols Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division, Code Division, Frequency Division Random partitioning (dynamic) ALOHA, S-ALOHA,

More information

Medium Access Protocols

Medium Access Protocols Medium Access Protocols Summary of MAC protocols What do you do with a shared media? Channel Partitioning, by time, frequency or code Time Division,Code Division, Frequency Division Random partitioning

More information

Lecture 6 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it

Lecture 6 The Data Link Layer. Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Lecture 6 The Data Link Layer Antonio Cianfrani DIET Department Networking Group netlab.uniroma1.it Link Layer: setting the context two physically connected devices: host-router, router-router, host-host,

More information

CMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 18

CMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 18 CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 18 1 Final project demo Please do the demo THIS week to the TAs. Or you are allowed to use

More information

CS 43: Computer Networks Switches and LANs. Kevin Webb Swarthmore College December 5, 2017

CS 43: Computer Networks Switches and LANs. Kevin Webb Swarthmore College December 5, 2017 CS 43: Computer Networks Switches and LANs Kevin Webb Swarthmore College December 5, 2017 Ethernet Metcalfe s Ethernet sketch Dominant wired LAN technology: cheap $20 for NIC first widely used LAN technology

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs Chapter 5 Link Layer and LANs A note on the use of these ppt slides: All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights Reserved Computer Networking: A Top Down Approach 4 th edition.

More information

CS 455/555 Intro to Networks and Communications. Link Layer Addressing, Ethernet, and a Day in the Life of a Web Request

CS 455/555 Intro to Networks and Communications. Link Layer Addressing, Ethernet, and a Day in the Life of a Web Request CS 455/555 Intro to Networks and Communications Link Layer Addressing, ernet, and a Day in the Life of a Web Request Dr. Michele Weigle Department of Computer Science Old Dominion University mweigle@cs.odu.edu

More information

Chapter 4. DataLink Layer. Reference: Computer Networking: A Top Down Approach 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007.

Chapter 4. DataLink Layer. Reference: Computer Networking: A Top Down Approach 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. Chapter 4 DataLink Layer Reference: Computer Networking: A Top Down Approach 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. DataLink Layer Link Layer 4.1 Link-Layer Addressing 4.2 Ethernet

More information

Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection:

Topics. Link Layer Services (more) Link Layer Services LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS. flow control: error detection: 1 Topics 2 LECTURE 5 MULTIPLE ACCESS AND LOCAL AREA NETWORKS Multiple access: CSMA/CD, CSMA/CA, token passing, channelization LAN: characteristics, i basic principles i Protocol architecture Topologies

More information

Link layer, LANs: outline. Chapter 5-2 Link Layer. MAC addresses (more) MAC addresses

Link layer, LANs: outline. Chapter 5-2 Link Layer. MAC addresses (more) MAC addresses Chapter 5-2 Link Layer Computer Networking: Top Down pproach 6 th edition Jim Kurose, Keith Ross ddison-wesley March 2012 Link layer, LNs: outline 5.1 introduction, services 5.2 error detection, correction

More information

Master Course Computer Networks IN2097

Master Course Computer Networks IN2097 Chair for Network Architectures and Services Prof. Carle Department for Computer Science TU München Master Course Computer Networks IN2097 Prof. Dr.-Ing. Georg Carle Christian Grothoff, Ph.D. Dr. Nils

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs Chapter 5 Link Layer and LANs A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you can add, modify, and

More information

Chapter 5 part 2 LINK LAYER. Computer Networks Timothy Roscoe Summer Networks & Operating Systems Computer Networks

Chapter 5 part 2 LINK LAYER. Computer Networks Timothy Roscoe Summer Networks & Operating Systems Computer Networks Chapter 5 part 2 LINK LAYER Computer Networks Timothy Roscoe Summer 2007 LAN technologies Data link layer so far services, error detection/correction, multiple access Next: LAN technologies LAN addressing,

More information

Master Course Computer Networks IN2097

Master Course Computer Networks IN2097 Chair for Network Architectures and Services Prof. Carle Department for Computer Science TU München Master Course Computer Networks IN2097 Prof. Dr.-Ing. Georg Carle Christian Grothoff, Ph.D. Chair for

More information

Links Reading: Chapter 2. Goals of Todayʼs Lecture. Message, Segment, Packet, and Frame

Links Reading: Chapter 2. Goals of Todayʼs Lecture. Message, Segment, Packet, and Frame Links Reading: Chapter 2 CS 375: Computer Networks Thomas Bressoud 1 Goals of Todayʼs Lecture Link-layer services Encoding, framing, and error detection Error correction and flow control Sharing a shared

More information

The Link Layer II: Ethernet

The Link Layer II: Ethernet Monday Recap The Link Layer II: Ethernet q Link layer services q Principles for multiple access protocols q Categories of multiple access protocols CSC 249 March 24, 2017 1 2 Recap: Random Access Protocols

More information

Discussions. What are the main service. Ch06 Link Layer. The Data Link Layer. Link Layer. Link Layer: Teminology. What are the services

Discussions. What are the main service. Ch06 Link Layer. The Data Link Layer. Link Layer. Link Layer: Teminology. What are the services Mobile network Discussions The Link Layer Yanmin Zhu Department of Computer Science and Engineering Global ISP Home network Regional ISP Institutional network What are the services provided by the link

More information

Link Layer: CSMA/CD, MAC addresses, ARP

Link Layer: CSMA/CD, MAC addresses, ARP Link Layer: CSM/CD, MC addresses, RP Smith College, CSC 249 March 29, 208 MC ddress q 32-bit IP address: network-layer address used to get datagram to destination IP subnet q MC (or LN, physical, thernet,

More information

Principles behind data link layer services:

Principles behind data link layer services: Data Link Layer Goals: Principles behind data link layer services: Error detection, correction Sharing a broadcast channel: multiple access Link layer addressing Reliable data transfer, flow control: Done!

More information

High Level View. EE 122: Ethernet and Random Access protocols. Medium Access Protocols

High Level View. EE 122: Ethernet and Random Access protocols. Medium Access Protocols High Level View EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 Goal: share a communication medium among multiple hosts connected to it Problem: arbitrate between connected hosts Solution goals:

More information

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services

Link Layer: Introduction. Chapter 5 Link Layer & LANS. Link layer: context. Link Layer Services Chapter 5 Link Layer & LANS Link Layer: Introduction Some terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are links wired links wireless

More information

Computer Networks Principles LAN - Ethernet

Computer Networks Principles LAN - Ethernet Computer s Principles LN - thernet Prof. ndrzej Duda duda@imag.fr Interconnection structure - layer subnetwork interconnection layer interconnection layer subnet subnet router switch (bridge) VLN http://duda.imag.fr

More information

Broadcast Links, Addressing and Media Access Control. Link Layer B. Link and Physical Layers. MAC Addresses

Broadcast Links, Addressing and Media Access Control. Link Layer B. Link and Physical Layers. MAC Addresses roadcast Links, ddressing and Media ccess Control Message M C Message M Link Layer In a broadcast, there are two additional issues that must be resolved How do the nodes agree on who gets to use the next?

More information

EE 122: Ethernet and

EE 122: Ethernet and EE 122: Ethernet and 802.11 Ion Stoica September 18, 2002 (* this talk is based in part on the on-line slides of J. Kurose & K. Rose) High Level View Goal: share a communication medium among multiple hosts

More information

More on Link Layer. Recap of Last Class. Interconnecting Nodes in LAN (Local-Area Network) Interconnecting with Hubs. Computer Networks 9/21/2009

More on Link Layer. Recap of Last Class. Interconnecting Nodes in LAN (Local-Area Network) Interconnecting with Hubs. Computer Networks 9/21/2009 More on Link Layer Kai Shen Recap of Last Class Ethernet dominant link layer technology for local-area l networks Ethernet frame structure Ethernet multiple access control CSMA/CD, exponential back-off

More information

Chapter V: Link Layer

Chapter V: Link Layer Chapter V: Link Layer UG3 Computer Communications & Networks (COMN) Myungjin Lee myungjin.lee@ed.ac.uk Slides copyright of Kurose and Ross Link layer services framing, link access: encapsulate datagram

More information

Link Layer Review. CS244A Winter 2008 March 7, 2008 Ben Nham

Link Layer Review. CS244A Winter 2008 March 7, 2008 Ben Nham Link Layer Review CS244A Winter 2008 March 7, 2008 Ben Nham Announcements PA3 due today PS3 due next Wednesday PA4 due next Friday Final Exam Review session next Friday 7-10 PM on Thursday, March 20 Multiple

More information

Link Layer and Ethernet

Link Layer and Ethernet Link Layer and Ethernet 14-740: Fundamentals of Computer Networks Bill Nace Material from Computer Networking: A Top Down Approach, 6 th edition. J.F. Kurose and K.W. Ross traceroute Data Link Layer Multiple

More information

Link Layer and Ethernet

Link Layer and Ethernet Link Layer and Ethernet 14-740: Fundamentals of Computer Networks Bill Nace Material from Computer Networking: A Top Down Approach, 6 th edition. J.F. Kurose and K.W. Ross traceroute Data Link Layer Multiple

More information

Reminder: Datalink Functions Computer Networking. Datalink Architectures

Reminder: Datalink Functions Computer Networking. Datalink Architectures Reminder: Datalink Functions 15-441 15 441 15-641 Computer Networking Lecture 5 Media Access Control Peter Steenkiste Fall 2015 www.cs.cmu.edu/~prs/15-441-f15 Framing: encapsulating a network layer datagram

More information

CSC 8560 Computer Networks: Link Layer

CSC 8560 Computer Networks: Link Layer CSC 8560 Computer Networks: Link Layer Professor Henry Carter Fall 2017 Last Time We talked about intra-as routing protocols: Which routing algorithm is used in RIP? OSPF? What techniques allow OSPF to

More information

CS 421: COMPUTER NETWORKS SPRING FINAL May 8, minutes

CS 421: COMPUTER NETWORKS SPRING FINAL May 8, minutes CS 421: COMPUTR NTWORKS SPRIN 2016 INL May 8, 2016 150 minutes Name: Student No: Q1 Q2 Q3 TOT 1) a) (6 pts) iven the following parameters for a datagram packet switching network: N: number of hops between

More information

LAN Interconnection and Other Link Layer Protocols

LAN Interconnection and Other Link Layer Protocols LAN Interconnection and Other Link Layer Protocols Ethernet dominant link layer technology for local-area networks Ethernet frame structure Kai Shen Dept. of Computer Science, University of Rochester Ethernet

More information

Chapter 5 Data Link Layer

Chapter 5 Data Link Layer Chapter 5 Data Link Layer Reti di Elaboratori Corso di Laurea in Informatica Università degli Studi di Roma La Sapienza Canale A-L Prof.ssa Chiara Petrioli Parte di queste slide sono state prese dal materiale

More information

Chapter V: Link Layer

Chapter V: Link Layer Chapter V: Link Layer UG3 Computer Communications & Networks (COMN) Myungjin Lee myungjin.lee@ed.ac.uk Slides copyright of Kurose and Ross Link layer: introduction terminology: hosts and routers: nodes

More information

Chapter 5 Data Link Layer

Chapter 5 Data Link Layer Chapter 5 Data Link Layer Reti degli Elaboratori Canale AL Prof.ssa Chiara Petrioli a.a. 2013/2014 We thank for the support material Prof. Kurose-Ross All material copyright 1996-2012 J.F Kurose and K.W.

More information

CSMA/CD (Collision Detection)

CSMA/CD (Collision Detection) CSMA/CD (Collision Detection) CD (collision detection): easy in wired LANs: measure signal strengths, compare transmitted, received signals difficult in wireless LANs: received signal strength overwhelmed

More information

Medium Access Control

Medium Access Control Medium Access Control All material copyright 1996-2009 J.F Kurose and K.W. Ross, All Rights Reserved 5: DataLink Layer 5-1 Link Layer Introduction and services Multiple access protocols Ethernet Wireless

More information

Chapter 5: DataLink Layer

Chapter 5: DataLink Layer Chapter 5: DataLink Layer Course on Computer Communication and Networks, CTH/GU The slides are adaptation of the slides made available by the authors of the course s main textbook Slides with darker background

More information

CS 3516: Advanced Computer Networks

CS 3516: Advanced Computer Networks Welcome to CS 3516: Advanced Computer Networks Prof. Yanhua Li Time: 9:00am 9:50am M, T, R, and F Location: Fuller 320 Fall 2017 A-term 1 Some slides are originally from the course materials of the textbook

More information

Module 10 Data Link Layer CS655! 10-1!

Module 10 Data Link Layer CS655! 10-1! Module 10 Data Link Layer CS655! 10-1! Please note: Most of these slides come from this book. Note their copyright notice below! A note on the use of these ppt slides: We re making these slides freely

More information

Computer Networks. Today. Principles of datalink layer services Multiple access links Adresavimas, ARP LANs Wireless LANs VU MIF CS 1/48 2/48

Computer Networks. Today. Principles of datalink layer services Multiple access links Adresavimas, ARP LANs Wireless LANs VU MIF CS 1/48 2/48 Computer Networks VU MIF CS 1/48 Today Principles of datalink layer services Multiple access links Adresavimas, ARP LANs Wireless LANs 2/48 1 Link layer: introduction terminology: hosts and routers: nodes

More information

Chapter 3 Part 2 Switching and Bridging. Networking CS 3470, Section 1

Chapter 3 Part 2 Switching and Bridging. Networking CS 3470, Section 1 Chapter 3 Part 2 Switching and Bridging Networking CS 3470, Section 1 Refresher We can use switching technologies to interconnect links to form a large network What is a hub? What is a switch? What is

More information

Chapter 5 Link Layer and LANs

Chapter 5 Link Layer and LANs Chapter 5 Link Layer and LANs Computer Networking: A Top Down Approach Featuring the Internet, A note on the use of these ppt slides: We re making these slides freely available to all (faculty, students,

More information

transferring datagram from one node data-link layer has responsibility of to adjacent node over a link 5-1 TDTS06 Computer networks

transferring datagram from one node data-link layer has responsibility of to adjacent node over a link 5-1 TDTS06 Computer networks TDTS06 Computer networks Lecture 7: The link layer I Link Layer: Introduction Some terminology: hosts and routers are nodes communication channels that connect adjacent nodes along communication path are

More information

CMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 16

CMPE 150/L : Introduction to Computer Networks. Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 16 CMPE 150/L : Introduction to Computer Networks Chen Qian Computer Engineering UCSC Baskin Engineering Lecture 16 1 Final project demo Please do the demo next week to the TAs. So basically you may need

More information

CSCI Computer Networks Spring 2017

CSCI Computer Networks Spring 2017 source: computer-networks-webdesign.com CSCI 6760 - Computer Networks Spring 2017 Instructor: Prof. Roberto Perdisci perdisci@cs.uga.edu These slides are adapted from the textbook slides by J.F. Kurose

More information

CSCI Computer Networks Fall 2016

CSCI Computer Networks Fall 2016 source: computer-networks-webdesign.com CSCI 4760 - Computer Networks Fall 2016 Instructor: Prof. Roberto Perdisci perdisci@cs.uga.edu These slides are adapted from the textbook slides by J.F. Kurose and

More information

Communication Networks ( ) / Spring 2011 The Blavatnik School of Computer Science, Tel-Aviv University. Allon Wagner

Communication Networks ( ) / Spring 2011 The Blavatnik School of Computer Science, Tel-Aviv University. Allon Wagner Communication Networks (0368-3030) / Spring 2011 The Blavatnik School of Computer Science, Tel-Aviv University Allon Wagner Kurose & Ross, Chapters 5.5-5.6 (5 th ed.) Tanenbaum & Wetherall, Chapters 4.3.4

More information

Chapter 5 Link Layer. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012

Chapter 5 Link Layer. Computer Networking: A Top Down Approach. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Chapter 5 Link Layer Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 All material copyright 1996-2012 J.F Kurose and K.W. Ross, All Rights Reserved

More information

ECE 4450:427/527 - Computer Networks Spring 2017

ECE 4450:427/527 - Computer Networks Spring 2017 ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 5.5: Ethernet Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527 Computer Networks

More information

Chapter 6 Connecting Device

Chapter 6 Connecting Device Computer Networks Al-Mustansiryah University Elec. Eng. Department College of Engineering Fourth Year Class Chapter 6 Connecting Device 6.1 Functions of network devices Separating (connecting) networks

More information

Link layer: introduction

Link layer: introduction Link layer: introduction terminology: hosts and routers: nodes communication channels that connect adjacent nodes along communication path: links wired links wireless links LANs layer-2 packet: frame,

More information

Computer Networks Medium Access Control. Mostafa Salehi Fall 2008

Computer Networks Medium Access Control. Mostafa Salehi Fall 2008 Computer Networks Medium Access Control Mostafa Salehi Fall 2008 2008 1 Outline Issues ALOHA Network Ethernet Token Ring Wireless 2 Main Issues Local Area Network (LAN) : Three or more machines are physically

More information

Lecture 6. Data Link Layer (cont d) Data Link Layer 1-1

Lecture 6. Data Link Layer (cont d) Data Link Layer 1-1 Lecture 6 Data Link Layer (cont d) Data Link Layer 1-1 Agenda Continue the Data Link Layer Multiple Access Links and Protocols Addressing Data Link Layer 1-2 Multiple Access Links and Protocols Two types

More information

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006

CS 123: Lecture 12, LANs, and Ethernet. George Varghese. October 24, 2006 CS 123: Lecture 12, LANs, and Ethernet George Varghese October 24, 2006 Selective Reject Modulus failure Example w = 2, Max = 3 0 0 1 3 0 A(1) A(2) 1 0 retransmit A(1) A(2) buffer Case 1 Case 2 reject

More information

7010INT Data Communications Lecture 7 The Network Layer

7010INT Data Communications Lecture 7 The Network Layer Introduction 7010INT Data Communications Lecture 7 The Layer Internetworking & Devices Connecting LANs Routing Backbone networks Virtual LANs Addressing Application Presentation Session Data Link Physical

More information

Redes de Computadores. Medium Access Control

Redes de Computadores. Medium Access Control Redes de Computadores Medium Access Control Manuel P. Ricardo Faculdade de Engenharia da Universidade do Porto 1 » How to control the access of computers to a communication medium?» What is the ideal Medium

More information

Chapter 6 The Link Layer and LANs. Chapter 6: Link layer and LANs. Link layer, LANs: outline

Chapter 6 The Link Layer and LANs. Chapter 6: Link layer and LANs. Link layer, LANs: outline Chapter 6 The Link Layer and LNs note on the use of these Powerpoint slides: We re making these slides freely available to all (faculty, students, readers). They re in PowerPoint form so you see the animations;

More information

Chapter 6: Link layer and LANs. Link layer, LANs: outline. Link layer: introduction. Link layer: context. Link layer services (more)

Chapter 6: Link layer and LANs. Link layer, LANs: outline. Link layer: introduction. Link layer: context. Link layer services (more) Chapter 6: Link layer and LANs our goals: understand principles behind layer services: error detection, sharing a broadcast channel: multiple access layer addressing local area networks: ernet, VLANs instantiation,

More information

Computer Networks. Wenzhong Li. Nanjing University

Computer Networks. Wenzhong Li. Nanjing University Computer Networks Wenzhong Li Nanjing University 1 Chapter 2. Direct Link Networks Link Service and Framing Error Detection and Reliable Transmission HDLC, PPP, and SONET Token Ring Ethernet Bridges and

More information

CSCD 330 Network Programming Spring 2017

CSCD 330 Network Programming Spring 2017 CSCD 330 Network Programming Spring 2017 Lecture 18 Link Layer Protocols Continued Who is this? Reading: Chapter 5 Some slides provided courtesy of J.F Kurose and K.W. Ross, All Rights Reserved, copyright

More information

INTRODUCTION, SERVICES. Data-link layer has responsibility of transferring datagram from one node to physically adjacent node over a link

INTRODUCTION, SERVICES. Data-link layer has responsibility of transferring datagram from one node to physically adjacent node over a link LINK LAYER 1 GOALS Understand principles behind link layer services: error detection, correction link layer addressing local area networks: Ethernet, VLANs, and data center networks 2 INTRODUCTION, SERVICES

More information

Chapter 5 Link Layer. Down Approach. Computer Networking: A Top. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012

Chapter 5 Link Layer. Down Approach. Computer Networking: A Top. 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Chapter 5 Link Layer Computer Networking: A Top Down Approach 6 th edition Jim Kurose, Keith Ross Addison-Wesley March 2012 Slides adopted from original ones provided by the textbook authors. Link layer,

More information

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017 CS 43: Computer Networks Media Access Kevin Webb Swarthmore College November 30, 2017 Multiple Access Links & Protocols Two classes of links : point-to-point dial-up access link between Ethernet switch,

More information

Chapter 5: Link layer

Chapter 5: Link layer Chapter 5: Link layer our goals: v understand principles behind link layer services: error detection, correction sharing a broadcast channel: multiple access link layer addressing local area networks:

More information

The Link Layer and LANs. Chapter 6: Link layer and LANs

The Link Layer and LANs. Chapter 6: Link layer and LANs The Link Layer and LANs EECS3214 2018-03-14 4-1 Chapter 6: Link layer and LANs our goals: understand principles behind link layer services: error detection, correction sharing a broadcast channel: multiple

More information

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018 CS 43: Computer Networks 27: Media Access Contd. December 3, 2018 Last Class The link layer provides lots of functionality: addressing, framing, media access, error checking could be used independently

More information

CSCD 330 Network Programming Winter 2016

CSCD 330 Network Programming Winter 2016 CSCD 330 Network Programming Winter 2016 Lecture 18 Link Layer Protocols Continued Who is this? Reading: Chapter 5 Some slides provided courtesy of J.F Kurose and K.W. Ross, All Rights Reserved, copyright

More information

Hubs, Bridges, and Switches (oh my) Hubs

Hubs, Bridges, and Switches (oh my) Hubs Hubs, Bridges, and Switches (oh my) Used for extending LANs in terms of geographical coverage, number of nodes, administration capabilities, etc. Differ in regards to: collision domain isolation layer

More information

ECE 4450:427/527 - Computer Networks Spring 2017

ECE 4450:427/527 - Computer Networks Spring 2017 ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 6.1: Internetworking Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527 Computer

More information

Lecture 6: Bridging & Switching. Last time. Today. CSE 123: Computer Networks Chris Kanich. How do multiple hosts share a single channel?

Lecture 6: Bridging & Switching. Last time. Today. CSE 123: Computer Networks Chris Kanich. How do multiple hosts share a single channel? Lecture 6: ridging & Switching SE 3: omputer Networks hris Kanich Project countdown: 5 days Last time How do multiple hosts share a single channel? Medium ccess ontrol (M) protocols hannel partitioning

More information

Underlying Technologies -Continued-

Underlying Technologies -Continued- S465 omputer Networks Spring 2004 hapter 3 (Part B) Underlying Technologies -ontinued- Dr. J. Harrison These slides were produced from material by Behrouz Forouzan for the text TP/IP Protocol Suite (2

More information

Computer Network Fundamentals Spring Week 3 MAC Layer Andreas Terzis

Computer Network Fundamentals Spring Week 3 MAC Layer Andreas Terzis Computer Network Fundamentals Spring 2008 Week 3 MAC Layer Andreas Terzis Outline MAC Protocols MAC Protocol Examples Channel Partitioning TDMA/FDMA Token Ring Random Access Protocols Aloha and Slotted

More information

LINK LAYER AND LANS 1

LINK LAYER AND LANS 1 LINK LAYER AND LANS 1 GOALS Understand principles behind link layer services: error detection, correction link layer addressing local area networks: Ethernet, VLANs, and data center networks Instantiation,

More information

Link Layer. 5.1 Introduction and services 5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.

Link Layer. 5.1 Introduction and services 5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5. Link Layer 5.1 Introduction and services 5.2 Error detection and correction 5.3Multiple access protocols 5.4 Link-Layer Addressing 5.5 Ethernet 5.6 Link-layer switches 5.7 PPP 5.8 Link Virtualization:

More information

Local Area Network. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7.

Local Area Network. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7. Review of Lecture 7 Local rea Network! Question - What are the station types supported by HDLC? Describe each. References: Chapters 15 and 16 Stallings Chapters 14 and 16 Forouzan Study Guide 8 Review

More information

Local Area Network Overview

Local Area Network Overview Local Area Network Overview Chapter 15 CS420/520 Axel Krings Page 1 LAN Applications (1) Personal computer LANs Low cost Limited data rate Back end networks Interconnecting large systems (mainframes and

More information

Introduction to Computer Networks. IEEE Ethernet

Introduction to Computer Networks. IEEE Ethernet Introduction to Computer Networks IEEE 802.3 Ethernet All rights reserved. No part of this publication and file may be reproduced, stored in a retrieval system, or transmitted in any form or by any means,

More information

CSE/EE 461 Lecture 7 Bridging LANs. Last Two Times. This Time -- Switching (a.k.a. Bridging)

CSE/EE 461 Lecture 7 Bridging LANs. Last Two Times. This Time -- Switching (a.k.a. Bridging) S/ 461 Lecture 7 ridging LNs Last Two Times Medium ccess ontrol (M) protocols Part of the Link Layer t the heart of Local rea Networks (LNs) ow do multiple parties share a wire or the air? Random access

More information

Chapter 5: The Data Link Layer

Chapter 5: The Data Link Layer Chapter 5: The Data Link Layer Our goals: principles behind data link layer services: error detection, correction sharing a broadcast channel: multiple access link layer addressing reliable data transfer,

More information

Physical and Link Layers. CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham

Physical and Link Layers. CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham Physical and Link Layers CS144 Review Session 6 November 6 th, 2008 Roger Liao Based on slides by Ben Nham Outline Physical layer Encoding of signals Chips vs. bits Link layer Communication through shared

More information

Lecture 6 - Link layer. Lecture 5 Review. Link Layer. Introduction, Services. Notes. Notes. Notes. Notes. Networks and Security. Jacob Aae Mikkelsen

Lecture 6 - Link layer. Lecture 5 Review. Link Layer. Introduction, Services. Notes. Notes. Notes. Notes. Networks and Security. Jacob Aae Mikkelsen Lecture 6 - Link layer Networks and Security Jacob Aae Mikkelsen IMADA October 21, 2013 October 21, 2013 1 / 91 Lecture 5 Review Explain in short the following abbreviations, and the concept behind it.

More information