All questions of Media Access Control (MAC) for Computer Science Engineering (CSE) Exam

Bluetooth utilizes frequency-hopping spread spectrum technology to avoid interference problems. The ISM 2.4 GHz band is 2400 to 2483.5 MHz, and Bluetooth uses 79 radio frequency channels in this band, starting at 2402 MHz and continuing every 1 MHz.

Introduction:
A wireless ad-hoc network is a type of network where devices communicate with each other without the need for a central access point (AP). Instead, the devices themselves act as both hosts and routers, dynamically forming a network on the fly. In this context, we will discuss whether an access point is required in a wireless ad-hoc network.

Explanation:
In a wireless ad-hoc network, the devices, also known as nodes, communicate directly with each other without the need for an access point. This is in contrast to traditional wireless networks where devices connect to an access point, which acts as a central hub for communication. Let's delve into the reasons why an access point is not required in a wireless ad-hoc network:

1. Autonomous Communication:
In a wireless ad-hoc network, each node is responsible for routing and forwarding data packets to other nodes. This autonomous communication eliminates the need for a central access point to manage and control the network.

2. Dynamic Network Formation:
Wireless ad-hoc networks are self-forming and self-healing, meaning that nodes can join or leave the network dynamically without disrupting the overall connectivity. Nodes can establish direct connections with nearby nodes to route data, forming a multi-hop network.

3. Infrastructure-less Network:
Unlike traditional wireless networks that rely on access points for connectivity, wireless ad-hoc networks are infrastructure-less. This makes them suitable for scenarios where setting up a centralized infrastructure is not feasible or desired, such as in disaster-stricken areas or military operations.

4. Increased Scalability:
Since there is no central access point, the number of nodes that can participate in the network is not limited by the capacity of a single access point. Wireless ad-hoc networks can scale to accommodate a large number of nodes, making them flexible and adaptable to various scenarios.

Conclusion:
In a wireless ad-hoc network, an access point is not required as the nodes themselves act as hosts and routers. The autonomous communication, dynamic network formation, infrastructure-less nature, and increased scalability of ad-hoc networks eliminate the need for a central access point.

Explanation:

In a piconet, which is a network of Bluetooth devices, there can be one master device and multiple slave devices. The master device is responsible for establishing and controlling the piconet, while the slave devices communicate with the master.

The question states that in the piconet of Bluetooth, one master device can be a slave in another piconet. Let's break down the options to understand why option 'B' is the correct answer.

a) Can not be slave:
If a device is the master in a piconet, it means that it has control over the piconet and is responsible for managing the communication between all the devices within that piconet. As such, a master device cannot act as a slave device within the same piconet. Therefore, option 'a' is incorrect.

b) Can be slave in another piconet:
While a master device cannot be a slave in the same piconet, it can act as a slave in another piconet. Bluetooth devices can simultaneously participate in multiple piconets, allowing a master device from one piconet to be a slave device in another piconet. This flexibility allows for more complex network configurations and enables devices to communicate with each other even if they are part of different piconets. Therefore, option 'b' is correct.

c) Can be slave in the same piconet:
As mentioned earlier, a master device cannot be a slave in the same piconet. Therefore, option 'c' is incorrect.

d) None of the mentioned:
Option 'd' is incorrect because, as explained above, a master device can be a slave in another piconet.

In conclusion, the correct answer is option 'B' - a master device can be a slave in another piconet. This flexibility allows for more versatile and interconnected Bluetooth networks.

IPv6 addresses have a size of 128 bits.

IPv6, which stands for Internet Protocol version 6, is the most recent version of the Internet Protocol. It was introduced to replace IPv4 due to the depletion of available IPv4 addresses. One of the main differences between IPv4 and IPv6 is the size of the addresses.

Understanding the size of IPv6 addresses

IPv6 addresses are 128 bits long, which is four times the length of IPv4 addresses. This increase in size provides a significantly larger address space, allowing for trillions of unique addresses. The larger address space of IPv6 was designed to accommodate the growing number of devices connected to the internet.

Benefits of 128-bit addressing

The 128-bit addressing scheme of IPv6 brings several benefits:

1. Address space: With 128 bits, IPv6 provides an enormous address space. It allows for approximately 340 undecillion unique addresses, which is more than enough to assign globally unique addresses to every device on the planet.

2. Efficiency: The larger address space eliminates the need for techniques like Network Address Translation (NAT), which were commonly used in IPv4 to conserve address space. With IPv6, each device can have a unique globally routable IP address.

3. Hierarchical addressing: IPv6 incorporates a hierarchical addressing structure, which simplifies routing and enhances network performance. The addressing structure consists of network prefixes and interface identifiers, enabling efficient routing and aggregation of addresses.

4. Address autoconfiguration: IPv6 supports stateless address autoconfiguration, allowing devices to generate their own IPv6 addresses based on network prefixes. This feature simplifies the process of assigning addresses to devices and enables plug-and-play functionality.

5. Improved security: IPv6 includes built-in security features such as IPsec, which provides encryption and authentication at the network layer. This enhances the security of communications over IPv6 networks.

In conclusion, IPv6 addresses have a size of 128 bits, which offers an enormous address space and brings numerous benefits compared to the smaller 32-bit IPv4 addresses.