Ethernet and IP Protocol

Ethernet and IP Protocol Overview

• Ethernet is a family of networking technologies defined by IEEE 802.2 and 802.3 standards that support wired communications
• IPv4 is a protocol that enables data exchange across networks
• IP Addressing Basics explains how IP addresses facilitate network communication
• Different categories of IPv4 addresses facilitate network communication
• The Default Gateway acts as an access point to another network, enabling network communication
• IPv6 is a protocol designed to replace IPv4, supporting network communication
• Ethernet encapsulation wraps data into Ethernet frames for transmission
• Ethernet Frame Size ranges from a minimum of 64 bytes to a maximum of 1518 bytes
• Collision Fragmentation discards Ethernet frames shorter than 64 bytes
• Jumbo Frames exceed 1500 bytes of data
• Preamble and Start Frame Limiter synchronizes devices in an Ethernet frame
• Destination MAC Address identifies the intended recipient of the Ethernet frame

IPv4 Addressing

• Source MAC Address identifies the originating network interface card (NIC)
• Type/Length field identifies the upper layer protocol encapsulated in the Ethernet frame
• Data Field contains encapsulated data from a higher layer, specifically an IPv4 packet
• Frame Check Sequence (FCS) detects frame errors using Cyclic Redundancy Check (CRC)
• MAC Address Format is a 48-bit binary value expressed as 12 hexadecimal digits
• Hexadecimal Digits use numbers 0-9 and letters A-F to represent binary data
• Network Layer provides services for devices to exchange data across networks
• IPv4 and IPv6 are principle network layer communication protocols
• Open Shortest Path First (OSPF) is a network layer protocol used for routing

Protocol Data Unit (PDU) Encapsulation and Packet Structure

• Routing is the process of selecting the best path for data packets and directing them to the destination host
• De-encapsulation is the process the destination host performs to extract the original data from a packet
• Packet Structure is specified by network layer protocols to carry data between hosts
• Connectionless: No connection established with the destination before sending data packets
• Best Effort: Characteristic of IP indicating packet delivery is not guaranteed
• Media Independent: Operation does not depend on the communication medium (copper, fiber, wireless)
• IP Header delivers packets to the destination and is examined by layer 3 devices
• Network Address Translation (NAT) process changes IP addressing information as packets are routed.
• Transport Layer Segments encapsulated by IP by adding an IP header

Protocols and Functions

• Low Overhead: Design characteristic of IP that allows efficient packet delivery
• Unreliable Network Layer Protocol: Does not guarantee packet delivery
• Control Information: Information exchanged to establish a connection when required
• Analogy of Connectionless communication: Conceptually similar to sending a letter without notifying the recipient beforehand
• OSI Data Link Layer prepares an IP packet for transmission over a communication medium
• Maximum Transmission Unit (MTU) is the maximum size of a Protocol Data Unit that a communication medium can transport
• IPv4 Packet Header ensures packet delivery to the next stop
• IPv4 Packet Header Fields (Version, DiffServ, Header Checksum, TTL, Protocol, Source IPv4 Address, Destination IPv4 Address) are included
• IPv4 Address is a 32-bit hierarchical address with network and host portions
• Network Portion bits are identical for devices on the same network
• Host Portion bits are unique to identify a specific host on a network
• Subnet Mask identifies network/host portion of IPv4 address

Subnetting and Addressing

• Subnet Mask Structure consists of consecutive sequences of 1 bits followed by 0 bits
• ANDing process identifies network and host portions of IPv4 address
• Prefix Length is the number of bits set to 1 in the subnet mask
• Slash Notation represents prefix length with a forward slash (/) followed by the number of bits set to 1
• Network Address (same as prefix or network prefix)
• Default Gateway is required to reach remote networks
• DNS Server translates domain names into IPv4 addresses
• IPv4 address assignment requires a unique host address and subnet mask
• Layer 3 process examines binary numbers in IPv4 packet headers
• Time to Live (TTL) is a field in the IPv4 Header
• Source IPv4 address and Destination IPv4 address are fields in the IPv4 header
• Header Checksum is a field in the IPv4 header
• Prefix Length: Number of 1 bits in the subnet mask
• IPv4 Address Representation: An IPv4 address followed by the prefix length (e.g., 192.168.10.10/24)
• Subnet Mask: A 32-bit address used with a host address to determine network

Addressing and Routing

• IPv4 address classes (A, B, C) have different ranges for addressing hosts.
• Private addresses (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) are used for internal networks
• Network Address Translation (NAT) translates private IPv4 addresses to public IPv4 addresses
• Default Gateway is the device that routes traffic outside the local network
• Traffic routing directs data packets
• IPv4 Default Gateway Configuration is dynamically assigned or manually configured
• IPv6 Default Gateway Configuration is advertised by the router or manually configured
• Default Route (path) is the pathway a computer uses to send traffic to another network
• Host Routing Table is displayed with commands like route print or netstat -r
• Netstat command output displays interface list, IPv4 route table, and IPv6 route table data

IPv6

• IPv6 Purpose is to succeed IPv4
• IPv6 Address Space is larger, supporting more addresses (128-bit) than IPv4 (32-bit)
• Transition to IPv6 is underway and is led by mobile providers and ISPs like YouTube, Facebook, and Netflix
• IPv6's depletion of IPv4 address space is a reason for transition. The expanding Internet of Things (IoT) is another reason. Computers, and several other communication devices and applications are part of the IoT.
• IPv6 Address Format is represented as hexadecimal values
• IPv6 is not case-sensitive
• IPv6 Address is divided into segments of 16 bits or hextets

Additional Information

• IPv6 address format, omitting leading zeros, example, and the use of double colons (::)
• IPv6 prefix length and examples of various formats

Classes, Addresses, and Addresses

• Different Classes of IPv4 addresses (A, B, C, D, E) support different numbers of hosts: Class A for large networks, Class B for medium-sized networks, and Class C for small networks; Class D and E are reserved
• Private IP addresses (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) are not routable on the Global Internet

Explore Ethernet (IEEE 802.2 and 802.3) and IPv4 protocols for wired communication and data exchange. Understand IP addressing, default gateways, and IPv6. Learn about Ethernet encapsulation, frame sizes, collision fragmentation, and the structure of Ethernet frames.