UCB Review — EECS 122 Jean Walrand U

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UCB Review - EECS 122 Jean Walrand U. C. Berkeley www. eecs. berkeley. edu/~wlr

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

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

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

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

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

IP UCB n n n Addressing IP Header TTL, Fragmentation, DS field Routing: OSPF, RIP, BGP, Multicast RED, RIO, etc Questions: n n n Steps of OSPF, RIP Why BGP? Why TTL, Fragmentation Why IPv 6? Pros/Cons of single class

MPLS & Diff. Serv UCB n n n Objectives Basic Mechanisms DRR etc; TCP/DRR Diff. Serv Admission Control Questions: n n Maximum rate for Diff. Serv Paths for MPLS

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

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

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

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

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

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

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

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

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

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

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

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