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