CHAPTER 9

                In this chapter, I have learned that Ethernet was designed for multiple hosts/computers which are interconnected within a shared topology, be accommodated. I’ve also learned that Ethernet technology’s foundation came from Alohanet in 1970 in Hawaii.  But in 1980, the first Ethernet standard was published. And in 1985, the IEEE (Institute of Electrical and Electronics Engineers) standards committee published standards for LANs. And this standard was 802.2 and 802.3, but the original standard was 802.3. the Ethernet divided the Data Link Layer into two sublayers: a) LLC (Logical Link Control); and b) MAC (Media Access Control). The 802.2 works in the upper sublayer (LLC) of the Data Link Layer, and the 802.3 works in the lower sublayer (MAC)of the Data Link Layer together with the Physical layer or the Layer 1.

                Ethernet’s frame has also several fields, the Preamble and Start Frame Delimiter, The Destination MAC Address, Source MAC Address, Length/ Type, Data and Pad, and Frame Check Sequence.

                CSMA/CD (Carrier Sense Multiple Access with Collision Detection was the first version of Ethernet’s media access method. When problems occurred during the attempts of multiple devices over a shared physical medium attempted to communicate, CSMA/CD manages that problem.

                I’ve also learned what is ARP or the Address Resolution Protocol. ARP is used by a host when it wants to have the MAC address of the other host. Then the requesting host sends ARP request into the network. Then the host in the network that has the IP address in the request then sends a reply with its MAC address.

KEY TERMS:

1.       IEEE

-          means Institute of Electrical and Electronics Engineers.

-          They are the one who published standards for the LAN’s/Ethernet.

2.       CSMA/CD

-          Means Carrier Sense Multiple Access with Collision Detection

-          It managed the problems that result when multiple computers attempt to communicate within a shared physical medium.

-          It controls the access to the shared media. It also detects collisions and frames are retransmitted.

3.       LLC

-          Means Logical Link Control

-          It is the upper sublayer of the Data Link layer. It makes the connection between the upper layers and it frames the network packet. It also identify the Network layer protocol and remains relatively independent of the physical equipment.

4.       MAC

-          Means Media Access Control

-          It is the lower sublayer of the Data Link layer. It gets data to the media. It has two primary responsibilities: 1) Data Encapsulation, which includes Frame delimiting, Addressing, Error Detection; 2) Media Access Control, which control the frame placement on and off the media and media recovery.

5.       MAN

-          Means Metropolitan Ares Network

-          A LAN applied across a city from being connected to single buildings, and then extended to between buildings.