CCNA Data Center Ethernet Communication Standards
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Transcript of CCNA Data Center Ethernet Communication Standards
CCNA Data CenterEthernet Communication
Standards
WHAT IS A LAN?
LAN COMPONENTS» Computers • PC and Servers» Interconnections • NICs and Media» Network Devices • Switches and Routers» Protocols • Ethernet, IP, ARP, DHCP
LAN FUNCTIONS
» Provides access to data and applications» Enables sharing of resources including
I/O devices (cameras and printers)» Connectivity to the Internet and other
networks
ETHERNET FROM THE 70S!Year Activity
1973 Eithernet invented at Xerox
1982 DIX releases 10Mbps Ethernet (version 2)
1983 IEEE approves 802.3 (10Base-5)
1985 IEEE approves 802.3a (10Base-2)
1990 IEEE approves 802.3i (10Base-T)
1995 IEEE approves 802.3u (100Base-TX)
1998 IEEE approves 802.3z (1Gbps)
2002 IEEE approves 802.3ae (10Gbps)
2010 IEEE approves 802.3ba (40Gbps & 100Gbps)
ETHERNET LAN STANDARDS» LAN protocols map to both OSI physical and
data link layers for cabling and signaling» IEEE 802.3 standard further divides the data link
layer into two sub layers • Logical Link Control (LLC) - Independent
function between network layer above and MAC layer
below • MAC – manages physical media access (MAC addresses)
CSMA/CD IN ETHERNET» Ethernet LANs manage signals on a network by using
Carrier Sense Multiple Access with Collision Detection or (CSMA/CD).
» Stations (Multiple Access) on a network can access the network at any time, but before sending data, they must determine whether or not is is already in use.
» If the network is not in use the station can then transmit.
» If the network is in use, the CSMA/CD station waits.
» A collision can occur if 2 stations, listen and hear nothing, then transmit simultaneously. Collisions damage the transmissions.
» After the collision occurs, stations must then retransmit.
ETHERNET FRAME FORMATPreamb
leDestination MAC
ADD.
Source MAC ADD.
Type/Length
Payload Frame Check
Sequence
(FCS)88 6 6 2 46-1500 4
» Ethernet II frames use EtherType to identify the upper layer protocol» IEEE 802.3 frames • Uses Start of Frame delimiter (SOF) – stealing 1 byte from Preamble • Uses Length in header to specify the length of the data field • IEEE 802.3 frames stores protocol information in the LLC layer between Length and Payload using DSAP, SSAP, and LLC CTL
UNICAST, BROADCAST, MULTICAST
» 3 major types of network communications • Unicast • Frame from 1 host to another host • Broadcast • Frame from 1 host to all hosts • Multicast • Frames from 1 host to a specific group of
hosts
ETHERNET ADDRESSES
» MAC addresses are assigned to the NIC card and often referred to as burned-in address or BIA
» MAC address are 48 bits long • 24 bits of Organizational Unique Identifier
(OUI) • 24 bits of vendor-assigned end station
address» Cisco MAC - 00:25:B5:00:11:00