Tài liệu hạn chế xem trước, để xem đầy đủ mời bạn chọn Tải xuống
1
/ 94 trang
THÔNG TIN TÀI LIỆU
Thông tin cơ bản
Định dạng
Số trang
94
Dung lượng
2,89 MB
Nội dung
Chapter9-EthernetCCNAExploration4.0 Học viện mạng Bách khoa - Website: www.bkacad.com Overview • Identify the basic characteristics of network media used in Ethernet. • Describe the physical and data link features of Ethernet. • Describe the function and characteristics of the media access control method used by Ethernet protocol. • Explain the importance of Layer 2 addressing used for data Học viện mạng Bách khoa - Website: www.bkacad.com • Explain the importance of Layer 2 addressing used for data transmission and determine how the different types of addressing impacts network operation and performance. • Compare and contrast the application and benefits of using Ethernet switches in a LAN as apposed to using hubs. • Explain the ARP process. Physical and Data Link Features of Ethernet • Standards and Implementation Học viện mạng Bách khoa - Website: www.bkacad.com Physical and Data Link Features of Ethernet IEEE (Electrical and Electronics Engineers) Standards • The first LAN is the original version of Ethernet. Robert Metcalfe and his coworkers at Xerox designed it more than thirty years ago. The first Ethernet standard was published in 1980 by a consortium of Digital Equipment Corporation, Intel, and Xerox (DIX).It was released as an open standard. The first Ethernet standard products were sold in the early 1980s. • Học viện mạng Bách khoa - Website: www.bkacad.com • In 1985, the IEEE standards committee for Local and Metropolitan Networks published standards for LANs. These standards start with the number 802, and 802.3 is for Ethernet. To compare to the International Standards Organization (ISO) and OSI model, the IEEE 802.3 standards had to address the needs of Layer 1 and the lower portion of Layer 2 of the OSI model. As a result, some small modifications to the original Ethernet standard were made in 802.3. • Ethernet operates in the lower two layers of the OSI model: the of the Data Link layer and the Physical layer. Physical and Data Link Features of Ethernet Học viện mạng Bách khoa - Website: www.bkacad.com Physical and Data Link Features of Ethernet Học viện mạng Bách khoa - Website: www.bkacad.com Physical and Data Link Features of Ethernet Học viện mạng Bách khoa - Website: www.bkacad.com • Media Access Control (MAC) is the lower Ethernet sublayer of the Data Link layer. MAC is implemented by hardware, typically in the computer Network Interface Card (NIC). • The Ethernet MAC sublayer has two primary responsibilities: – Data Encapsulation – Media Access Control • Logical Topology: all the nodes (devices) in that network segment share the medium. This requires examining the addressing in the frame provided by the MAC address, and using of CSMA/CD. Physical and Data Link Features of Ethernet Học viện mạng Bách khoa - Website: www.bkacad.com Physical and Data Link Features of Ethernet • Most of the traffic on the Internet originates and ends with Ethernet connections. Since its inception in the 1970s, Ethernet has evolved to meet the increased demand for high-speed LANs. When optical fiber media was introduced, Ethernet adapted to this new technology to take advantage of the superior bandwidth and low error rate that fiber offers. Today, the same protocol that Học viện mạng Bách khoa - Website: www.bkacad.com rate that fiber offers. Today, the same protocol that transported data at 3 Mbps can carry data at 10 Gbps. • The success of Ethernet is due to the following factors: – Simplicity and ease of maintenance – Ability to incorporate new technologies – Reliability – Low cost of installation and upgrade Physical and Data Link Features of Ethernet Học viện mạng Bách khoa - Website: www.bkacad.com [...]... (Gigabit) Ethernet is used Some of the equipment and cabling in modern, well-designed and installed networks may be capable of working at the higher speeds with only minimal upgrading This reduces the total cost H c vi n m ng Bách khoa - Website: www.bkacad.com Characteristics of Network Media used in Ethernet • The increased cabling distances enabled by the use of fiber-optic cable in Ethernet- based... ng Bách khoa - Website: www.bkacad.com Naming on EthernetEthernet uses MAC addresses that are 48 bits in length and expressed as 12 hexadecimal digits •Sometimes referred to as burned-in addresses (BIA) because they are burned into read-only memory (ROM) and are copied into random-access memory (RAM) when the NIC initializes H c vi n m ng Bách khoa - Website: www.bkacad.com Layer 2 addressing and... and subsequent data traffic increase, however, the rise in collisions can have a significant impact on the user's experience H c vi n m ng Bách khoa - Website: www.bkacad.com Characteristics of Network Media used in Ethernet Current Ethernet • 100BASE-TX Ethernet Switches replace hubs • Switches can control the flow of data by isolating each port and sending a frame only to its proper destination (if... is generally the unicast address of the transmitting Ethernet node (can be virtual entity – group or multicast) H c vi n m ng Bách khoa - Website: www.bkacad.com Ethernet frame structure Length if value < 1536 decimal, (0x600) need LLC to identify upper protocol 4 bytes CRC •The type value specifies the upper-layer protocol to receive the data after Ethernet processing is completed •The length indicates... Support full-duplex communications (transmit and receive signals at the same time) • 1Gbps Ethernet and beyond H c vi n m ng Bách khoa - Website: www.bkacad.com Characteristics of Network Media used in Ethernet • The applications tax even the • • most robust networks For example, the increasing use of Voice over IP (VoIP) and multimedia services requires connections that are faster than 100 Mbps Ethernet. .. Bách khoa - Website: www.bkacad.com Layer 2 addressing and its Impact on Network Operation and Performance • Ethernet Unicast H c vi n m ng Bách khoa - Website: www.bkacad.com Layer 2 addressing and its Impact on Network Operation and Performance H c vi n m ng Bách khoa - Website: www.bkacad.com Layer 2 addressing and its Impact on Network Operation and Performance H c vi n m ng Bách khoa - Website:... www.bkacad.com Ethernet Media Access Control H c vi n m ng Bách khoa - Website: www.bkacad.com Function and Characteristics of the Media Access Control Method H c vi n m ng Bách khoa - Website: www.bkacad.com Function and Characteristics of the Media Access Control Method H c vi n m ng Bách khoa - Website: www.bkacad.com Function and Characteristics of the Media Access Control Method H c vi n m ng Bách khoa - Website:... fail without disrupting the entire network However, repeating the frame to all other ports did not solve the issue of collisions H c vi n m ng Bách khoa - Website: www.bkacad.com Characteristics of Network Media used in Ethernet Legacy Ethernet • In 10BASE-T networks, typically using a hub This created a shared media Only one station could successfully transmit at a time: halfduplex communication • More... Ethernet is 1500 octets, so the data should not exceed that size Ethernet requires that the frame be not less than 46 octets or more than 1500 octets (Pad is required if not enough data) •Type if value => 1536 decimal, (0x600) protocol it identify upper H c vi n m ng Bách khoa - Website: www.bkacad.com Layer 2 addressing and its Impact on Network Operation and Performance H c vi n m ng Bách khoa -. ..Characteristics of Network Media used in Ethernet H c vi n m ng Bách khoa - Website: www.bkacad.com Characteristics of Network Media used in Ethernet • Early Ethernet Media: Coaxial cable • – Logical and physical bus topology – 10BASE5, or Thicknet, used a thick coaxial that allowed for cabling distances . faster than 100 Mbps Ethernet. • 100 0 Mbps (Gigabit) Ethernet is Học viện mạng Bách khoa - Website: www.bkacad.com • 100 0 Mbps (Gigabit) Ethernet is used Chapter 9 - Ethernet CCNA Exploration 4. 0 Học viện mạng Bách khoa - Website: www.bkacad.com Overview • Identify