Exam #2 Topics - CS442
The exam is closed book and closed notes, but you are allowed a one page 8.5
X 11 "cheat sheet" where you can put down whatever material you wish, both
sides. Calculators are also allowed if you feel that one is
necessary. The exam topics are listed below:
Transmission Media
- Characteristics of the different types of
transmission media
- Shannon's equation and Nyquist bandwidth
- Guided and Unguided media
- Twisted Pair, Coax, Fiber
- Wireless too: microwave, infrared, radio
- Major characteristics of each media (attenuation, distance,
supported data rates)
Modulation and Data Encoding
- Digital transmission of digital data - Manchester Encoding format
- Analog transmission of digital data
- Frequency domain concepts
- Bandwidth and relationship to accuracy of signal reproduction
- Frequency and Time Division Multiplexing
- Modulation
- Phase modulation
- Amplitude modulation
- Frequency modulation
- Tradeoffs of above; e.g. which has more problems with noise, etc.
- Comboning above techniques to send multiple bits per symbols
- bps vs. baud rate, difference
- Analog transmission of digital data
- Basics of Pulse Amplitude Modulation and PCM (Pulse Code
Modulation)
- Relationship between sampling rate, quantization and data rate and
quantizing error
- Impact of PCM on modem performance
- Modulation techniques that could (or can) be used in cable modems, xDSL,
idea of adaptive transmission
Packet / Frame based transmission
- Transmission efficiency vs. packet size
- Transparency problem and bit stuffing
- Concept of forward error checking, where it is useful
- LAN Topologies
- Star, Bus, Ring, Tree
- Tradeoffs of above
- How data is propagated in a bus and ring
- How collisions are detected in a bus
- How a star can behave as a logical bus or as a true star
- Details of Ethernet: CSMA/CD
- Media Access Control method
- How collisions are detected
- What happens when a collision occurs, e.g. binary exponential
backoff
- Changes with Gigabit Ethernet
- Details of Token Ring
- Media Access Control method
- Performance vs. Ethernet
- Changes with FDDI
- Details of Wireless Ethernet 802.11, CSMA/CA
- Media Access Control Method
- How it differs from wired ethernet, e.g. hidden station problem
- Ethernet packets and addressing
- Role addressing plays in filtering packets, even in a broadcast
environment how this helps performance
- Ethernet address format
- Special addresses, e.g. broadcast and multicast
- Where ethernet addresses come from
- Ethernet frame formats
- How the two formats are distinguished
- Fields of each format and what they mean
- Maximum Transmission size
- What "Best Effort" means with Ethernet
LAN Hardware
- Difference between a bridge, hub, switch, router, repeater
- Common wiring schemes
- How bridges and switches learn ethernet addresses
- Why a spanning tree must be built
- What a spanning tree is
WANS and Routing
- Purpose of a CSU/DSU
- Leasing Point to Point connections from the telco
- T , DS, OC, STS standards for communication media specifications
- Physical Addressing in a WAN
- Packet Switches
- Hierarchical address (switch, port)
- Next hop forwarding and routing tables
- What needs to be stored in a routing table, simplification of routing
tables
- Routing Theory
- Tradeoffs of Link State vs. Distance Vector algorithms
- Overview of how Dijkstra's Algorithm works
- Details of how the Distance Vector algorithm works
- Be able to compute distance vector routing tables
- Count to infinity problem
- Recompute routing tables when link cost changes
- Routing Protocols
- Static vs. Dynamic, tradeoffs, where each are used
- Concept of an Autonomous System
- Routing within an Autonomous System, between Autononous Systems
- Details of RIP
- Overview of OSPF
- Some details of BGP
- How a router's switching fabric is implemented