CMSC506 Study Guide for Midterm Exam

CMSC506 Study Guide for Midterm Exam

CMSC506 study guide for final exam

Question format:

  • Term explanations: e.g., what is CSMA/CD?
  • Short question: e.g., what is the hidden node problem and what causes this problem.
  • Simple math and terminology: e.g., calculating effective data rate for Ethernet.
  • Protocol tracing: Explain binary countdown algorithm and its motivation.
  • What is binary exponential backoff algorithm? Where is it being used?

Scope:

  • Mostly after midterm.
  • Network Layer, Chapter 5, Mainly on 5.2 and 5.6
  • Routing Related Topics
  • The fundamental routing scheme is store-and-forward
  • 5.2.2 Should be able to step-by-step construct Shortest Path Routing path for a given graph. You should be very familiar with Figure 5-7.
  • 5.2.3 The pros and cons of flooding. How to improve it?
  • 5.2.4 Distance Vector Routing: focus on updating process. The main drawback of DVR: count-to-infinity problem
  • 5.2.5 Link state Routing: each node will calculate routing table when received enough information. Notice how link stage packet is defined and passed around.
  • 5.2.6 Hierarchical routing: able to determine the size of routing table when the hierarchical structure is given.
  • 5.2.7 Broadcasting routing: spanning tree and reverse path forwarding
  • Internet Related Topics
  • 5.5.6-7 Internetwork routing, Fragmentation
  • 5.6.1 understand various fields in IPv4 header, such as TTL and MF. The IP routing options (strict and loose source) and their functionality. When studying these, always ask yourself why a particular IP feature is their.
  • 5.6.2 Subnet and netmask.
  • 5.6.3 ICMP types. ARP and RARP. Keep in mind that these are IP level protocols. But the functionalities of ARP and RARP is to translate IP and MAC address.
  • 5.6.8 IPv6. Difference when compared to IPv4.
  • Media Access Layer: mainly at 4.1 4.2 4.3 4.4 4.5 and some subsection in 4.6 and 4.7.
  • Understand three types of access methods:
  • Fixed channel allocation: FDMA, TDMA. Often centralized.
  • Dynamic allocation with collision: ALOHA, CSMA/CD, CSMA/CA
  • Dynamic allocation and collision-free: bit-map, binary countdown…
  • 4.1.1 and 4.1.2 basic concepts and terms.
  • 4.2.1 the difference between pure aloha and slotted aloha. The vulnerable period.
  • 4.2.2 CSMA and several variations. Persistent or not. Augmented by collision detection (Figure 4.5).
  • 4.2.3 collision free protocols. pros and cons. Efficiency calculation.
  • 4.2.6 wireless properties: range, hidden node and exposed node. MACA, collision avoidance.
  • 4.3 Ethernet related topics
  • 4.3.1 4.3.2 Basic specifications: physical dimension, physical media, speeds. Signal forms.
  • 4.3.2 Frame format, collision detection in Ethernet. Propagation delay, minimum packet size.
  • 4.3.4 Binary Exponential Backoff algorithm: what is its purpose?
  • 4.3.7 and 4.3.8 switched Ethernet and gigabit Ethernet
  • 4.4 WLAN related topics: basic protocol is also at 4.2.6
  • 4.4.1-4.4.2 physical layer specification andDifferent versions in 802.11 family
  • 4.4.3 RTS/CTS handshake, and Network Allocation Vector. Figure 4.27. Fragmentation transmission.
  • DCF and PCF operation mode in 802.11.
  • Base station (AP), beacon frame and channels in 802.11
  • 4.4.4 802.11 framing.
  • 4.5.1 Compare 802.11 and 802.16
  • 4.6.1 bluetooth
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