CCNA3-1 Chapter 2-1 Chapter 2Chapter 2 Switch Concepts and Switch Concepts and Configuration Configuration Part IPart I CCNA3-2 Chapter 2-1 Switch Concepts and ConfigurationSwitch Concepts and Configuration Key Elements ofKey Elements of Ethernet/802.3 LANsEthernet/802.3 LANs CCNA3-3 Chapter 2-1 CSMA/CDCSMA/CD CCNA3-4 Chapter 2-1 Ethernet CommunicationsEthernet Communications Unicast:Unicast: oneone toto oneone Unicast:Unicast: oneone toto oneone Unicast:Unicast: oneone toto oneone Broadcast:Broadcast: oneone toto allall Broadcast:Broadcast: oneone toto allall Broadcast:Broadcast: oneone toto allall Multicast:Multicast: oneone toto manymany Multicast:Multicast: oneone toto manymany Multicast:Multicast: oneone toto manymany CCNA3-5 Chapter 2-1 Ethernet CommunicationsEthernet Communications •• Ethernet Frame: Ethernet Frame: Minimum 64 bytes, Maximum 1518 bytesMinimum 64 bytes, Maximum 1518 bytes •• Preamble/SOFD:Preamble/SOFD: Synchronize to medium.Synchronize to medium. •• Destination Address: Destination Address: MAC Address of destination device.MAC Address of destination device. •• Source Address: Source Address: MAC address of source device.MAC address of source device. •• Length/Type: Length/Type: Length of frame or protocol type code.Length of frame or protocol type code. •• Data: Data: Encapsulated data from OSI Layers 7 to 3.Encapsulated data from OSI Layers 7 to 3. •• FCS: FCS: Frame Check Sequence.Frame Check Sequence. CCNA3-6 Chapter 2-1 Ethernet CommunicationsEthernet Communications •• MAC Address: MAC Address: 12 hexadecimal digits12 hexadecimal digits •• Broadcast:Broadcast: Indicates a broadcast or multicast frame.Indicates a broadcast or multicast frame. •• Local:Local: indicates whether the address can be modified locally.indicates whether the address can be modified locally. •• OUI Number:OUI Number: Manufacturer of the NIC.Manufacturer of the NIC. •• Vendor Number:Vendor Number: Unique, vendor assigned number.Unique, vendor assigned number. CCNA3-7 Chapter 2-1 Ethernet CommunicationsEthernet Communications CCNA3-8 Chapter 2-1 Ethernet CommunicationsEthernet Communications •• Switch Port Settings:Switch Port Settings: •• AUTO:AUTO: •• AutoAuto negotiation of duplex mode. The two ports negotiation of duplex mode. The two ports communicate to determine the best mode.communicate to determine the best mode. •• Default for FastEthernet and 10/100/1000 ports.Default for FastEthernet and 10/100/1000 ports. •• FULL:FULL: •• FullFull duplex mode.duplex mode. •• Default for 100BASEDefault for 100BASE FX ports.FX ports. •• HALF:HALF: •• HalfHalf duplex mode.duplex mode. Configuration commands later in the chapter.Configuration commands later in the chapter. CCNA3-9 Chapter 2-1 Ethernet CommunicationsEthernet Communications •• Switch Port Settings:Switch Port Settings: •• AUTO:AUTO: •• AutoAuto negotiation of duplex mode. The two ports negotiation of duplex mode. The two ports communicate to determine the best mode.communicate to determine the best mode. •• AutoAuto negotiation can produce unpredictable results.negotiation can produce unpredictable results. •• If autoIf auto negotiation fails negotiation fails because the attached device because the attached device does not support it, the Catalyst switch defaults the does not support it, the Catalyst switch defaults the switch port to switch port to halfhalf duplex modeduplex mode •• HalfHalf duplex on one end and fullduplex on one end and full duplex on the other duplex on the other causes late collision errorscauses late collision errors at the halfat the half duplex end. duplex end. •• To avoid this, manually set the duplex parameters of To avoid this, manually set the duplex parameters of the switch to match the attached device. the switch to match the attached device. CCNA3-10 Chapter 2-1 Ethernet CommunicationsEthernet Communications •• Switch Port Settings:Switch Port Settings: •• AutoAuto MDIX feature:MDIX feature: •• In the past, either a crossIn the past, either a cross over or a straightover or a straight through through cable was required depending on the type of device cable was required depending on the type of device that was being connected to the switch.that was being connected to the switch. •• Instead, the mdix auto interface configuration Instead, the mdix auto interface configuration command enables the command enables the automatic mediumautomatic medium dependent dependent interface crossover (autointerface crossover (auto MDIX)MDIX) feature.feature. •• With this feature enabled, the switch detects the With this feature enabled, the switch detects the interface required for copper media and configures the interface required for copper media and configures the interface accordingly.interface accordingly. Configuration commands later in the chapter.Configuration commands later in the chapter. [...]... broadcast domain • Only Layer 3 devices or a VLAN form separate broadcast domains CCNA3 -22 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • Network Latency: • Latency is the time a frame or a packet takes to travel from the source to the final destination CCNA3 -23 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • Network Congestion: • The primary reason for segmenting a LAN into smaller parts... Increasing volume of network traffic • High-bandwidth applications High- CCNA3 -24 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • LAN Segmentation: • LANs are segmented into a number of smaller collision and broadcast domains using routers and switches Broadcast Hub CCNA3 -25 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • LAN Segmentation: • LANs are segmented into a number of smaller collision... JAM JAM JAM Collision JAM JAM JAM JAM JAM JAM JAM JAM Hub CCNA3 -26 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • LAN Segmentation: • LANs are segmented into a number of smaller collision and broadcast domains using routers and switches Collision Domains Broadcast Domain Switch CCNA3 -27 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • LAN Segmentation: • LANs are segmented into a number of... Domains Domains Router CCNA3 -28 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • LAN Segmentation: • LANs are segmented into a number of smaller collision and broadcast domains using routers and switches CCNA3 -29 Chapter 2- 1 LAN Design Considerations • There are two primary considerations when designing a LAN: • Controlling network latency • Removing bottlenecks CCNA3-30 Chapter 2- 1 LAN Design Considerations... addresses will be recorded in the table CCNA3-11 Chapter 2- 1 Switch MAC Address Table • Example Step 1: • The switch receives a broadcast frame from PC 1 on Port 1 CCNA3- 12 Chapter 2- 1 Switch MAC Address Table • Example Step 2: • The switch enters the source MAC address and the switch port that received the frame into the address table CCNA3-13 Chapter 2- 1 Switch MAC Address Table • Example Step 3: • Because... provide dedicated bandwidth to each network segment segment CCNA3 -21 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • Broadcast Domains: • Although switches filter most frames based on MAC Interconnecting addresses, they do not filter broadcast frames frames switches extends the • Why? broadcast domain • Because a switch runs at Layer 2 and cannot learn the MAC address FFFFFFFFFFFF FFFFFFFFFFFF •... frame, it must read further into the frame than a Layer 2 device, which creates a longer processing time CCNA3- 32 Chapter 2- 1 LAN Design Considerations • Removing Network Bottlenecks: • Each workstation and the server are connected at 1000Mbps Add 4 workstations If all additional 1000Mbps NICs to at access the server the same time server CCNA3-33 Chapter 2- 1 Switch Concepts and Configuration Forwarding Frames... destroyed • The sending hosts stop sending based on the Ethernet 8 02. 3 rules of CSMA/CD • It is important to understand that when stating the bandwidth of the Ethernet network is 10 Mb/s, full bandwidth for transmission is available only after any collisions have been resolved resolved CCNA3-18 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • Bandwidth and Throughput: • A major disadvantage of Ethernet... are collision domains • When a host is connected to a switch port, the port, switch creates a dedicated connection This connection is an individual collision domain domain CCNA3 -20 Chapter 2- 1 Design Considerations – Ethernet/8 02. 3 • Microsegment: • When two connected hosts want to communicate with each other, the switch uses the switching table to establish a connection between the ports • The circuit... ports, except the port on which it received the frame frame CCNA3-14 Chapter 2- 1 Switch MAC Address Table • Example Step 4: • The destination device replies to the broadcast with a unicast frame addressed to PC 1 1 CCNA3-15 Chapter 2- 1 Switch MAC Address Table • Example Step 5: • The switch enters the source MAC address of PC 2 and the port number of the switch port that received the frame into the address . CCNA3-1 Chapter 2- 1 Chapter 2Chapter 2 Switch Concepts and Switch Concepts and Configuration Configuration Part IPart I CCNA3 -2 Chapter 2- 1 Switch Concepts and ConfigurationSwitch. Configuration Key Elements ofKey Elements of Ethernet/8 02. 3 LANsEthernet/8 02. 3 LANs CCNA3-3 Chapter 2- 1 CSMA/CDCSMA/CD CCNA3-4 Chapter 2- 1 Ethernet CommunicationsEthernet Communications Unicast:Unicast: oneone. effect on the throughputeffect on the throughput CCNA3 -20 Chapter 2- 1 Design Considerations Design Considerations –– Ethernet/8 02. 3Ethernet/8 02. 3 •• Collision Domains:Collision Domains: •• To reduce