Direct Link Lan

Direct Link Networks ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Encoding ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Bits NRZ 0 0 1 0 1 1 1 1 0 1 0 0 0 0 1 0

Problems: Consecutive 1s or 0s ,[object Object],[object Object],[object Object],[object Object]

Alternative Encodings ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Encodings (cont) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Encodings (cont) Bits NRZ Clock Manchester NRZI 0 0 1 0 1 1 1 1 0 1 0 0 0 0 1 0

Framing ,[object Object],[object Object],Frames Bits Adaptor Adaptor Node B Node A

Approaches ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Header Body 8 16 16 8 CRC Beginning sequence Ending sequence

Approaches (cont) ,[object Object],[object Object],[object Object],[object Object],[object Object]

Approaches (cont) ,[object Object],[object Object],[object Object]

Handling Errors ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Error Detecting and Correcting Codes ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Error Detection Techniques ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Cyclic Redundancy Check ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

CRC (cont) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

CRC Example Generator 1101 11111001 10011010 000 Message 1101 1001 1101 1000 1101 1011 1101 1100 1101 1000 1101 101 Remainder

Choice of C(x) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Error Detection Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Error Recovery ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Summary ,[object Object],[object Object],[object Object],[object Object]

Shared Media and Local Area Networks ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Multiple Access Links and LANs ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Typical LAN Structure ROM Ethernet Processor ,[object Object],[object Object],[object Object],RAM RAM

Adaptors Communicating ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],sending node rcving node network packet adapter adapter link layer protocol frame frame

MAC (Physical) Addresses ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

MAC (Physical, or LAN) Addresses ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

MAC Sub-layer Data link layer 802.3 CSMA-CD 802.5 Token Ring 802.2 Logical link control Physical layer MAC LLC 802.11 Wireless LAN Network layer Network layer Physical layer OSI IEEE 802 Various physical layers Other LANs

Broadcast Links: Multiple Access ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Random Access ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Controlled Access ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Taxonomy of MAC Protocols WiFi (802.11)

Pure (unslotted) Aloha ,[object Object],[object Object]

Slotted Aloha ,[object Object],[object Object],[object Object],Success (S), Collision (C), Empty (E) slots

Performance of Aloha Protocols S = throughput = “goodput” (success rate) G = offered load = Np 0.5 1.0 1.5 2.0 0.1 0.2 0.3 0.4 Pure Aloha Slotted Aloha

Carrier Sense Multiple Access ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Persistent and Non-persistent CSMA ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

CSMA/CD ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Worst Case Collision Detection Time

Ethernet Overview ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Dest addr 64 48 32 CRC Preamble Src addr Type Body 16 48

Ethernet ,[object Object],[object Object],[object Object],[object Object],[object Object],Metcalfe’s Ethernet sketch

Ethernet Frame Format ,[object Object],DIX frame format IEEE 802.3 format ,[object Object],[object Object],[object Object],[object Object],Dest addr 8 bytes 6 4 CRC Preamble Src addr Type Data 2 6 0-1500 Dest addr 8 bytes 6 4 CRC Preamble Src addr Length Data 2 6 0-1500

Fields in Ethernet Frame Format ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

IEEE 802.3 MAC: Ethernet ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

IEEE 802.3 Parameters ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Ethernet MAC Protocol: Basic Ideas ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Ethernet CSMA/CD Alg. Flow Chart

Ethernet CSMA/CD Algorithm ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Ethernet’s CSMA/CD (more) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

CSMA/CD Efficiency ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

IEEE 802.3 Physical Layer IEEE 802.3 10 Mbps medium alternatives Thick Coax: Stiff, hard to work with T connectors flaky Hubs & Switches! (a) transceivers (b) Point-to-point link Star Bus Bus Topology 2 km 100 m 2 00 m 5 00 m Max. Segment Length Optical f iber T wisted pair Thin coax Thick coax Medium 10base FX 10base T 10base 2 10base 5

Ethernet Technologies: 10Base2 ,[object Object],[object Object],[object Object],[object Object],[object Object]

10BaseT ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],hub nodes

Ethernet Hubs & Switches Twisted Pair Cheap Easy to work with Reliable Star-topology CSMA-CD Twisted Pair Cheap Bridging increases scalability Separate collision domains Full duplex operation (a)       Single collision domain (b)     High-Speed backplane or interconnection fabric

Evolution of Ethernet ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

100Base T (Fast) Ethernet: Issues ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Fast (100Mbps) Ethernet IEEE 802.3 100 Mbps Ethernet medium alternatives ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Star Star Star Topology 2 km 100 m 100 m Max. Segment Length Optical fiber multimode Two strands Twisted pair category 5 UTP two pairs Twisted pair category 3 UTP 4 pairs Medium 100baseFX 100baseT 100baseT4

Gigabit Ethernet Gigabit Ethernet Physical Layer Specification (IEEE 802.3 1 Gigabit Ethernet medium alternatives) Star Star Star Star Topology 100 m 25 m 5 km 550 m Max. Segment Length Twisted pair category 5 UTP Shielded copper cable Optical fiber single mode Two strands Optical fiber multimode Two strands Medium 1000baseT 1000baseCX 1000baseLX 1000baseSX

Gigabit Ethernet ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Carrier Extension ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],RRRRRRRRRRRRR Frame Carrier Extension 512 bytes

Frame Bursting ,[object Object],[object Object],[object Object],[object Object],512 bytes Extension Frame Frame Frame Frame Frame burst

10 Gigabit Ethernet IEEE 802.3 10 Gbps Ethernet medium alternatives ,[object Object],[object Object],[object Object],[object Object],[object Object],300 m – 10 km 40 km 10 km 300 m Max. Segment Length Two optical fibers multimode/single-mode with four wavelengths at 1310 nm band 8B10B code Two optical fibers Single-mode at 1550 nm SONET compatibility Two optical fibers Single-mode at 1310 nm 64B66B Two optical fibers Multimode at 850 nm 64B66B code Medium 10GbaseLX4 10GbaseEW 10GBaseLR 10GbaseSR

Typical Ethernet Deployment Server 100 Mbps links 10 Mbps links Server Server Server 100 Mbps links 10 Mbps links Server 100 Mbps links 10 Mbps links Server Gigabit Ethernet links Gigabit Ethernet links Server farm Department A Department B Department C Hub Hub Hub Ethernet switch Ethernet switch Ethernet switch Switch/router Switch/router

Ethernet Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Token based Multiple Access ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Token Ring (IEEE 802.5) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Token Ring Performance ,[object Object],where

Token Release T oken Frame T oken Frame Release after Transmission Release after Reception

Tokens and Data Frames Body Checksum Src addr Variable 48 Dest addr 48 32 End delimiter 8 Frame status 8 Frame control 8 Access control 8 Start delimiter 8

Token Ring Frame Fields ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Priority and Reservation ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Ring Maintenance ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Fault Scenarios ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Token Ring Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Ethernet vs Token Ring ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

FDDI ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

FDDI vs. 802.5 (Token Ring) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Timed Token Algorithm ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Timed Token Algorithm (cont) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Summary (continued) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Summary (continued) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Summary (continued) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Direct Link Lan

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