Chapter 2.3 Describe Ethernet and ERP (Ethernet Evolution (-Since 1973…
Chapter 2.3 Describe Ethernet and ERP
-most widely used in LAN technology
-Define IEEE 802.2 and 802.3 standards
-Support bandwidth of 10Mb/s,100Mb/s,1000 Mb/s(1 Gb/s), 10000Mb/s(10Gb/s),40000Mb/s(40Gb/s),and 100000Mb/s (100Gb/s).
-Operates in the data link layer and pyhisical layer
The Ethernet LLC sublayer handles the comunication between upper layer and the lower layer.
-The MAC sublayer contitutes the lower sublayer of the data link
;2 primary responsibilities-Data encapsulation
-media access control
-Since 1973,Ethernet standards have evolved specifying faster&more flexible versions of the technology
-Early version of Ethernet were relatively slow at 10Mbps.
-The latest versions of Ethernet operate at 10Gigabit per second and faster
Ethernet Frame Fields
-The minimum Ethernet frame size from destination MAC address to FCS is 64 bytes & the max is 1518 bytes.
-Frames less than 64 bytes are called a "collision fragment" or "runt frame" & are automatically discarded by rereceiving stations.Frames greater than 1500 bytes of data are consider "jumbo" or "baby giant frames"
-If the size of a transmitted frame is less than the minimum or greater than the maximum,the receiving device drops the frame.
Ethernet Mac Address
(MAC Address and Hexadecimal)
-An Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits
-Hexadecimal is used to represent Ethernet MAC address and IP Version 6 address.
-Convert to decimal or hexa value to binary,and then convert to binary value to decimal / hexa as needed
-MAC Address were created to identify the actual source & destination.
;The MAC address rules are establish by IEEE
-IEEE requires a vendor to follow two simple rules;
:All MAC address assigned to a NIC or other Ethernet device must use that vendor's assigned OUI as the first 3 bytes
:All MAC addresses with the same OUI must be assigned a unique value in the last 3 bytes.
-The MAC address is often referred as a burned-in address(BIA) meaning the address is encoded into the ROM chip permanently.When the comp start boots up the first thing that NIC does is copy the MAC address from ROM into RAM
-When a device is forwading a message to an Ethernet network,it attaches header information to the frame
-The header information contains the source and destination MAC address
MAC Address Representations
-Used the ipconfig/all command on a Windows host to identify the MAC address of an Ethernet adapter.On a MAC or Linux host,the ifconfig command is used.
-Depending on the device & the os,you will see various representation of MAC addresses
Unicast MAC Address
-Unique address used when a frame is sent from a single transmitting device to a single destination device.
-For a unicast packet to be sent & received,a destination IP address must be in the IP packet header & a corresponding destination MAC address must also be present in the Ethernet frame header
Broadcast MAC Address
-Many network protocol,such as DHCP and ARP, use broadcast
-A broadcast packet contains a destination IPv4 address that has all ones(1s) in the host portion indicating that all hosts on that local network will receive and process the packet
-When the IPv4 broadcast packet is encapsulated in the Ethernet frame,the destination MAC address is the broadcast MAC address is the broadcast MAC address of FF-FF-FF-FF-FF-FF in hexadecimal
Multicast MAC Address
-Multicast address allows a source device to send a packet to a group of devices.
-Devices in a multicast group are assigned a multicast group IP address in the range of 22.214.171.124 to 126.96.36.199(IPv6 multicast addresses begin with FF00::/8).
-The multicast IP addresse requires a corresponding multicast MAC address that begin with 01-00-5E in hexadecimal