UCB
Review - EECS122
Jean Walrand
U.C. Berkeley
www.eecs.berkeley.edu/~wlr
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
How Networks Work
UCB






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
Layers
UCB

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
DNS
UCB


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
IP
UCB






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
MPLS & DiffServ
UCB





Objectives
Basic Mechanisms
DRR etc; TCP/DRR
DiffServ Admission Control
Questions:


Maximum rate for DiffServ
Paths for MPLS
Multiple Access
UCB

TDM, FDM, CDMA


Aloha


Throughput, Delay Calculations
Ethernet


Throughput, Delay Calculations
Reservation Aloha


Understand pros and cons
CSMA/CD Operations
Questions:

Calculate rates, delays, …
Switches
UCB

Input, Output, VOB, Shared, Modular





Understand Operations
Pros and Cons
Scheduling
Classification
Questions:



Throughput comparisons
Delay comparisons
QoS Possibilities
Performance Models
UCB

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(Xk)
E(T)
Physical Layer
UCB

Digital Link:




Modulation Schemes:



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:



Manchester, On/Off optical, QAM on copper
SONET: Synchronize transmitters; protection with rings
DSL: Divide bandwidth into 4kHz channels; modulate
channels based on SNR
Wireless
UCB

Three Generations:


Cellular:


Frequency reuse; Handoff
Wireless LAN:


Analog/Digital Circuits/Packets
Multiple Access (Reservation)
Ad-Hoc:

Hop-by-hop with adaptive routing
Optical Networks
UCB

Generations:


Devices:


Optical Links; O/E/O Circuits; O Circuits;
O. Burst Switching;
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)
Security
UCB

Components:


Crypto (public and secret); Hashing
Systems:

Confidentiality; Authentication; Integrity
Compression
UCB

Types:


Lossless and Lossy
Examples:




Huffman
Lempel-Ziv
Block Codes
Motion Prediction
UCB
Example: Network
ATM/ADSL
Ethernet
ATM
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



Optical Network in Core
WEB over Wireless
New services:



New networks (?)



Video Conferencing, Web Television, ?
CDN, Storage(?), …
Sensors
Robust, Integrated
After TCP/IP?