Ethernet LAN Technologies
Ethernet LAN Technologies
Section titled âEthernet LAN TechnologiesâEthernet is the dominant LAN technology used in CCNA networking. It defines wired local area network media, frame formats, addressing, and access methods.
Ethernet Standards
Section titled âEthernet Standardsâ- 10BASE-T: 10 Mbps over twisted-pair copper using star topology.
- 100BASE-TX: 100 Mbps Fast Ethernet over twisted-pair copper.
- 1000BASE-T: 1 Gbps Gigabit Ethernet over twisted-pair copper.
- 10GBASE-T: 10 Gbps Ethernet over twisted-pair copper.
- 100BASE-FX and 1000BASE-SX/LX: Fiber optic Ethernet standards.
Media and Cabling
Section titled âMedia and Cablingâ- Twisted-pair copper: UTP categories 5e, 6, and 6a are common.
- Fiber optic: Used for longer distances and reduced interference.
- Coaxial: Legacy technology, not used in modern CCNA labs.
Ethernet Frame Structure
Section titled âEthernet Frame StructureâEthernet frames include:
- Preamble and Start Frame Delimiter (SFD)
- Destination MAC address
- Source MAC address
- EtherType/Length field
- Payload (data)
- Frame Check Sequence (FCS)
MAC Addresses
Section titled âMAC Addressesâ- 48-bit MAC addresses are used for hardware addressing.
- MAC addresses are represented in hexadecimal.
- Switches use MAC address tables to forward frames within a LAN.
Switching and Collision Domains
Section titled âSwitching and Collision Domainsâ- Ethernet uses switches to reduce collision domains.
- Each switch port represents a separate collision domain.
- Full-duplex operation eliminates collisions on point-to-point links.
Access Methods
Section titled âAccess Methodsâ- Ethernet originally used CSMA/CD on shared media.
- Modern switched Ethernet uses full duplex and does not rely on CSMA/CD.
Summary
Section titled âSummaryâEthernet LAN technologies are fundamental to CCNA. Understanding standards, cabling, frame format, and MAC addressing is essential for network design and troubleshooting.