Question

Answer the following questions with citing references :-

1. What are the 3 private IP address ranges for IPv4? How many usable IP addresses does each range have?

2. What is the purpose of private IP addresses (sometimes incorrectly called non-routable IP addresses)? How are they used?

3. What are the components of MAC addresses? How are MAC addresses assigned?

4. What is a layer 3 / multilayer ethernet switch? How does it differ from a traditional switch? Why does the name "layer 3 switch" seem somewhat odd at first glance?

Answer 1

1. 3 private IP address ranges

• 10.0.0.0 to 10.255.255.255 | Total usable IP addresses 65,536
• 172.16.0.0 to 172.31.255.255 | Total usable IP addresses 1,048,576
• 192.168.0.0 to 192.168.255.255 | Total usable IP addresses 16,777,216

2. We need private IP because the total amount public IP addresses quickly grow too big . The total number available is 3000 million addresses after taking out the reserved ranges. You can probably imagine that this easily outstrips the number of devices that need to connect to the Internet.so to overcome this we have private IP address which works behind a single public IP.

3. Media Access Control address is a universal number assigned to devices which is connected to a network, and also we can referred as physical address. MAC addresses are 6-byte (48-bits) in length.The first 3-bytes are ID number of the manufacturer, which is assigned by an ISP . The second 3-bytes are serial number assigned by the manufacturer.

Before a manufacturer can build products that connects to network , it must ask the IEEE to assign the manufacturer a universally unique 3-byte code, called the organizationally unique identifier (OUI). then the manufacturer usually give a number called network interface controller (NIC) by combining OUI and NIC ,MAC forms.

4. Layer 3 switch is capable of having IP addresses and doing routing. For extra-VLAN communication, it uses the IP routing table. For intra-VLAN communication, it uses the MAC address table.but other switches like Layer 2 uses only MAC addresses to switch the packets from a port to the destination port.Layer 3 switches is widely used to improve network routing performance on large local area networks