UCB Review - EECS122 Jean Walrand U.C. Berkeley

UCB Topics How Networks Work: Internet, Ethernet, ATM Layers: IETF, IEEE, ATM, SONET DNS TCP IP MPLS/DiffServ Multiple Access: TDMA, …, Ethernet, Aloha Switches Performance Models PHY: Sonet, DSL, Modulation, … Wireless Optical Networks Security Compression

UCB How Networks Work Key Ideas: Packets; IP/Link or LAN Applications: HTTP, CDN, VoIP IP Addressing, packet by packet -> Scalable End-to-end principle Ethernet: MAC address, ARP, … ATM: VC … Questions: Address translations Why is this scalable, extensible Describe packet formats, sequence of messages

UCB Layers IETF: APP/TCP, UDP/IP/MPLS/LINK, LAN/PHY IEEE: LLC/MAC/PHY for Ethernet ATM: AAL/ATM SONET: PATH/LINK/SECTION … Questions: Describe the layers of IP/ATM/Sonet How about IP/Sonet

UCB DNS Structure and Protocol Questions: How is this scalable Reliability Caching Sequence of messages

UCB TCP Go Back N Numbering of ACKs Flow Control: Receiver-Advertised Window Slow Start – Congestion Avoidance RTT and timeout estimation Additive Increase – Multiplicative Decrease Justification: Try to be fair and efficient Improvements Fast Retransmit Fast Recovery RED, RIO Vegas

UCB IP Addressing IP Header TTL, Fragmentation, DS field Routing: OSPF, RIP, BGP, Multicast RED, RIO, etc Questions: Steps of OSPF, RIP Why BGP? Why TTL, Fragmentation Why IPv6? Pros/Cons of single class

UCB MPLS & DiffServ Objectives Basic Mechanisms DRR etc; TCP/DRR DiffServ Admission Control Questions: Maximum rate for DiffServ Paths for MPLS

UCB Multiple Access TDM, FDM, CDMA Understand pros and cons Aloha Throughput, Delay Calculations Reservation Aloha Throughput, Delay Calculations Ethernet CSMA/CD Operations Questions: Calculate rates, delays, …

UCB Switches Input, Output, VOB, Shared, Modular Understand Operations Pros and Cons Scheduling Classification Questions: Throughput comparisons Delay comparisons QoS Possibilities

UCB Performance Models Basic Queuing Model: M/M/1 Poisson arrivals, Exponential lengths P(X = n), E(X), E(T) Network of M/M/1 Queues Each queue has same occupancy distribution as if it were M/M/1 with arrival rate given by flow conservation equations E(X k ) E(T)

UCB Physical Layer Digital Link: bits -> [MOD] -> signals -> [DEM] -> bits Add error detection DEM: Clock recovery + bit detection Modulation Schemes: Baseband: self-clocking or not Broadband: for wireless, for FDM, to exploit channel bandwidth Examples: Manchester, On/Off optical, QAM on copper SONET: Synchronize transmitters; protection with rings DSL: Divide bandwidth into 4kHz channels; modulate channels based on SNR

UCB Wireless Three Generations: Analog/Digital Circuits/Packets Cellular: Frequency reuse; Handoff Wireless LAN: Multiple Access (Reservation) Ad-Hoc: Hop-by-hop with adaptive routing

UCB Optical Networks Generations: Optical Links; O/E/O Circuits; O Circuits; O. Burst Switching; Devices: O. Amplifier; Wavelength Converters; Optical Switch; O. Memory; WDM Conclusions: O Circuits in the core: Fast provisioning, protection switching; In core, routers can fill up a wavelength In MAN: WDM (O. Links)

UCB Security Components: Crypto (public and secret); Hashing Systems: Confidentiality; Authentication; Integrity

UCB Compression Types: Lossless and Lossy Examples: Huffman Lempel-Ziv Block Codes Motion Prediction

UCB Example: Network Ethernet ATM/ADSL ATM Point-to-Point IP link (DHCP; framing) ATM VC (UBR) IP/ATM/SONET SONET PATH

UCB Example: Applications Network Application Servers, Content Servers Caches, Storage, Traffic Shapers, Redirection Agents, Processing

UCB Speculations: Future Optical Network in Core WEB over Wireless New services: Video Conferencing, Web Television, ? CDN, Storage(?), … New networks (?) Sensors Robust, Integrated After TCP/IP?