Topic 2. Lecture 4. Internet (cn)
1. Give the difference between a MAC and an IP address.
Media Access Control Address (MAC) - It’s an identifier for the specific hardware and known as physical address or hardware address. It had its own unique address and be easily identified the network that may use your device’s address.
Internet Protocol (IP) - It’s an identifier that’s labeled numerically to a particular device on the network that uses TCP/IP to interact, and the address that uses the network can not be identified outside the network.
2. Explain each section of the IP Address Header
VERs - A 4-bit field that identifies the IP version being used. The current version is 4, and this version is referred to as IPv4.
HLEN - A 4-bit field containing the length of the IP header in 32-bit increments. The minimum length of an IP header is 20 bytes, or five 32-bit increments. The maximum length of an IP header is 24 bytes, or six 32-bit increments. Therefore, the header length field should contain either 5 or 6.
SERVICE TYPE - The 8-bit ToS uses 3 bits for IP Precedence, 4 bits for ToS with the last bit not being used. The 4-bit ToS field, although defined, has never been used.
TOTAL LENGTH - Specifies the length of the IP packet that includes the IP header and the user data. The length field is 2 bytes, so the maximum size of an IP packet is 216 – 1 or 65,535 bytes.
INDETIFICATION, DF, MF and FRAGMENT OFFSET - As an IP packet moves through the Internet, it might need to cross a route that cannot handle the size of the packet. The packet will be divided, or fragmented, into smaller packets and reassembled later. These fields are used to fragment and reassemble packets.
TIME TO LIVE - It is possible for an IP packet to roam aimlessly around the Internet. If there is a routing problem or a routing loop, then you don't want packets to be forwarded forever. A routing loop is when a packet is continually routed through the same routers over and over. The TTL field is initially set to a number and decremented by every router that is passed through. When TTL reaches 0 the packet is discarded.
PROTOCOL - In the layered protocol model, the layer that determines which application the data is from or which application the data is for is indicated using the Protocol field. This field does not identify the application, but identifies a protocol that sits above the IP layer that is used for application identification.
HEADER CHECKSUM - A value calculated based on the contents of the IP header. Used to determine if any errors have been introduced during transmission.
SOURCE ADDRESS - 32-bit IP address of the sender.
DESTINATION ADDRESS - 32-bit IP address of the intended recipient.
IP OPTIONS and DATA - A field that varies in length from 0 to a multiple of 32-bits. If the option values are not a multiple of 32-bits, 0s are added or padded to ensure this field contains a multiple of 32 bits.
List the different IP Address classes within its corresponding details
Class A, 1.0.0.1 to 126.255.255.254
Class B, 128.1.0.1 to 191.255.255.254
Class C, 192.0.1.1 to 223.255.254.254
Class D, 224.0.0.0 to 239.255.255.255
Class E, 240.0.0.0 to 254.255.255.254
3. Identify the IP version 4 public addresses and IP version 4 private addresses
IP version 4 public addresses:
Private Class A range 10.0.0.0 - 10.255.255.255
Private Class B range 172.16.0.0-172.31.255.255
Private Class C range 192.168.0.0-192.168.255.255
Loopback Addresses 127.0.0.0-127.255.255.255
IP version 4 private addresses:
11.x.x.x - 126.255.255.255
129.0.0.0 - 169.253.255.255
169.255.0.0 - 172.15.255.255
192.0.3.0 - 192.88.98.255
192.88.100.0 - 192.167.255.255
192.169.0.0 - 198.17.255.255
198.20.0.0 - 223.255.255.255
4. Identify the difference between IP version 4 and IP version 6 addresses
IPv4 addresses are 32 bit length. IPv6 addresses are 128 bit length.
IPv4 addresses are binary numbers represented in decimals. IPv6 addresses are binary numbers represented in hexadecimals.
No packet flow identification. Packet flow identification is available within the IPv6 header using the Flow Label field.
Checksum field is available in IPv4 header No checksum field in IPv6 header.
Options fields are available in IPv4 header. No option fields, but IPv6 Extension headers are available.
Address Resolution Protocol (ARP) is available to map IPv4 addresses to MAC addresses. Address Resolution Protocol (ARP) is replaced with a function of Neighbor Discovery Protocol (NDP).
Internet Group Management Protocol (IGMP) is used to manage multicast group membership. IGMP is replaced with Multicast Listener Discovery (MLD) messages.
Broadcast messages are available. Broadcast messages are not available. Instead a link-local scope "All nodes" multicast IPv6 address (FF02::1) is used for broadcast similar functionality.
Manual configuration (Static) of IPv4 addresses or DHCP (Dynamic configuration) is required to configure IPv4 addresses. Auto-configuration of addresses is available in IPv6.
5. Give the differences between TCP and UCP
TCP stands for “Transmission Control Protocol” while UDP stands for “User datagram Protocol”.
TCP is connection oriented protocol while UDP is connectionless protocol.
TCP is more reliable than UDP.
UDP is more faster for data sending than TCP.
UDP makes error checking but no reporting but TCP makes checks for errors and reporting.
TCP gives guarantee that the order of data at receiving end is same as on sending end while UDP has no such guarantee.
Header size of TCP is 20 bytes while that of UDP is 8 bytes.
TCP is heavy weight as it needs three packets to setup a connection while UDP is light weight.
TCP has acknowledgement segments but UDP has no acknowledgement.
TCP is used for application that require high reliability but less time critical whereas UDP is used for application that are time sensitive but require less reliability.
6. Explain what is a subnet and subnet addressing.
A subnet is an identifiably separate part of an organization's network. A portion of a network that shares a common address component. On TCP/IP networks, subnets are defined as all devices whose IP addresses have the same prefix.
Subnet addressing known as a subnet mask because it is used to identify network address of an IP address by performing a bitwise AND operation on the netmask. A Subnet mask is a 32-bit number that masks an IP address, and divides the IP address into network address and host address.
Explain VLSM and identify its purpose.
A Variable Length Subnet Mask (VLSM) is a numerical masking sequence, or IP address subset, based on overall network requirements. A VLSM allows a network administrator to use long masks for networks with few hosts and short masks for networks with multiple hosts. A VLSM is used with a VLSM router and must have routing protocol support.
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