CCN Module: III : Local Area Networks( 25 Marks ) By Kamal Rochlani

N.B: Questions printed in different color were asked in Mumbai University exams.

Multiple access communications (Q: 1) Write short on: Multiple access Communications 08 OR What is multiple access communication system? What is Collision? Why user stations have to share the Transmission medium? Explain different Medium sharing Techniques. 08

Local Area Network (LAN) Structure

(Q: 2) Define LAN with typical LAN Structure. Also explain what is Network Interface Card (NIC) or LAN adapter card? 04 (Q:3) Write short note on: LAN Standards 10 OR Write short note on: IEEE 802 committee 10 OR Write short note on: IEEE Project 802 10 OR Write short note on: IEEE standards 10 OR Write short note on: IEEE 802 LAN standards 10

The Medium Access Control (MAC) sub layer , The Logical Link Control (LLC) Layer

(Q:4) Explain the standardized protocol architectures for a LANs which encompasses physical, Medium Access Control (MAC) & Logical Link Control (LLC) layers. 10 OR Write short note on: Medium Access Control (MAC) sub layer 10 OR Write short note on: Logical Link Control (LLC) sub layer / IEEE 802.2 Standard 10 OR What is the role of LLC? 4

Random Access to medium access Control (MAC)

(Q: 5) When do Random Access to MAC methods are used? What are different Random Access MAC methods? 2

Pure ALOHA & Slotted ALOHA

(Q:6) Write short note on ALOHA. 5 OR Explain Pure ALOHA & Slotted ALOHA. 5 (Q:7) Derive the formula for measuring the efficiency of the ALOHA system & Explain how the efficiency is increased for slotted ALOHA. 10

OR What is ALOHA ? Derive the expression for slotted & pure ALOHA. 10 OR For ALOHA draw the offered load Vs throughput graph. Also show when the maximum throughput is achieved. 8

OR Show that the maximum throughput of pure ALOHA is 1/2e. 10

BE EXTC SEM VII -2- CCN QB By Kamal Rochlani (Q:8) Compare ALOHA techniques. 8

CSMA (Q:9) Explain CSMA & also explain the three persistence protocols that can be used with CSMA. 10

CSMA/CD & CSMA/CA

(Q:10) Explain CSMA/CD and its use what part of 802 project uses CSMA/CD. 10

OR Explain CSMA/CD procedure with the help of flow chart. What is binary exponential back off method? What the Role of jam signal? 10 (Q:11) What is Collision & collision domain? How collision & collision domain can be reduced? How collision can be Detected? Explain CSMA/CD. 10 (Q:12) IS it possible to avoid the collisions in the broadcast media? Explain with protocols. 8 OR Write short note on : CSMA /CA Procedure. 10 (Q:13) Compare the performance of Pure ALOHA, Slotted ALOHA, 1-P CSMA, and Non P CSMA & Non P CSMA/CD. 10

Scheduling Approaches to medium access control (MAC) : Reservation systems, Polling, token passing rings

(Q:14) When do Scheduling techniques are used? What are different Scheduling techniques? 2 (Q:15) Discuss various scheduling methods used in medium access control. 10 OR Explain following TDM access techniques: 1. Reservation 2. Polling 3.Token Passing 10 Sub questions: How does Reservation work in Medium Access Control? 5 Write short note on: IEEE 802.5 token ring standard 6 OR Draw the frame format of token ring 802.5 4

OR How do low priority station gains the token in 802.5 standards? 4

Comparison of random access & Scheduling medium access controls (Q:16) Compare between Random Access & scheduling medium access control. 05

IEEE 802.3 standard for 10 Mbps (Ethernet) (Q:17) Write short note on : Ethernet / IEEE 802.3 standard for 10 Mbps LAN 10 OR With respect to 802.3 explain: 8

1. Transceiver & Transceiver cable

BE EXTC SEM VII -3- CCN QB By Kamal Rochlani

2. Frame format 3. Error Handling 4. Repeaters & Bridges

IEEE 802.3 standard for 1000 Mbps (Gigabit Ethernet)

(Q:18) Write short note on : Gigabit Ethernet / IEEE 802.3 standard for 1000 Mbps LAN 10

Repeaters & Hubs, LAN Bridges, LAN Switches (Q:19) What is internetworking? Describe the devices used in the internetworking. 10 OR Write short note on : Hubs , Bridges, Routers, Repeaters & Switches 10 OR List the various networking & internetworking devices & explain their working in detail with help of Neat sketches. 10

(Q:20) What do we mean we say that a bridge can filter traffic? Why filtering is important? 5

Transparent Bridges (Q:21) Explain Transparent Bridges. Also show how bridge learning takes place with appropriate example. 10

Source Routing Bridges (Q:22) Write short note on : Source routing Bridges. 05

Mixed media Bridges (Q:23) Write short note on : Mixed Media Bridges / Bridges connecting different LANs. 05

Spanning Tree Algorithm (Q:24) Write short on: Spanning Tree Algorithm 10 OR Explain the spanning tree algorithm with reference to frame forwarding. Address learning & loop resolution. 10