Tài liệu giảng dạy CCNA - module 04 chapter 14-LAN Switching Review and Configuring Cisco 2950 LAN Switches

 Upon completion of this chapter, you will be able to perform the following tasks:  Describe Layer 2 switching bridging operations  Describe the Catalyst 2950 switch operations  Con

Module 04 LAN Switching

Chapter 14 LAN Switching Review and Configuring Cisco

2950 LAN Switches

 Upon completion of this chapter, you will be able to

perform the following tasks:

 Describe Layer 2 switching (bridging) operations

 Describe the Catalyst 2950 switch operations

 Configure Catalyst 2950 switch

 Use show commands to verify Catalyst 2950

switch configuration and operations

1 LAN SWITCHING REVIEW

How Switches Learn Host Locations

• Initial MAC address table is empty

MAC address table

How Switches Learn Hosts Locations

• Station A sends a frame to Station C

• Switch caches station A MAC address to port E0 by learning

the source address of data frames

• The frame from station A to station C is flooded out to all

ports except port E0 (unknown unicasts are flooded)

MAC address table

How Switches Learn Host Locations

• Station D sends a frame to station C

• Switch caches station D MAC address to port E3 by learning the source Address of data frames

• The frame from station D to station C is flooded out to all ports

except port E3 (unknown unicasts are flooded)

MAC address table

C

How Switches Filter Frames

 Station A sends a frame to station C

 Destination is known, frame is not flooded

E0: 0260.8c01.1111

E2: 0260.8c01.2222

E1: 0260.8c01.3333 E3: 0260.8c01.4444 0260.8c01.1111

Broadcast and Multicast Frames

• Station D sends a broadcast or multicast frame

• Broadcast and multicast frames are flooded to

all ports other than the originating port

Transmitting Frames through a

Switch

Transmitting Frames through a

Switch

 Cut-through

 Switch checks destination address

and immediately begins forwarding

frame

Frame

 Fragment free

(modified cut-through)—Cat1900 Default

 Switch checks the first 64 bytes then immediately

begins forwarding frame

Frame

 Store and forward

 Complete frame is received and checked before forwarding

Duplex Overview

Half duplex (CSMA/CD)

• Unidirectional data flow

• Higher potential for collison

• Hubs connectivity

Switch Hub

Full duplex

• Point-to-point only

• Attached to dedicated switched port

• Requires full-duplex support on both ends

• Collision free

• Collision detect circuit disabled

2 CONFIGURING CISCO 2950 LAN

SWITCHES

Configuring the Switch

 Catalyst 2950

 IOS CLI (command-line interface)

 Web-based VSM (Visual Switch Manager)

Basic Administrative

configurations

Basic Administrative

configurations

 A switch should be given a hostname, and passwords

should be set on the console and vty lines

Configuring the Switch IP Address & default

Speed and Duplex Options

ASLSwitch(config)#interface f0/1

ASLSwitch(config-if)#

duplex {auto | full| half}

Speed {10|100|1000|auto|negociate}

Enable Web server

 Intelligent networking devices can provide a web-based

interface for configuration and management purposes

 ALSwitch(config)#ip http server

 ALSwitch(config)#ip http port 8080

 Any additional software such as an applet, can be

downloaded to the browser from the switch

Configuring Static MAC Addresses

 It may be decided that it is desirable for a MAC address to

be permanently assigned to an interface

 To set a static MAC address entry for a switch:

 Switch(config)#mac-address-table static <mac-address

of host> FastEthernet <FastEthernet numer> vlan <vlan

number>

 To remove this entry use the no form of the command:

 Switch(config)#no mac-address-table static

<mac-address of host> interface FastEthernet <Ethernet

number> vlan <vlan name>

Configure Port Security

 ALSwitch(config)#interface f0/2

 ALSwitch(config-if)#port security ?

 action action to take for security violation

 max-mac-count maximum mac address count

 <cr>

 ALSwitch(config-if)#port security action ?

 shutdown shut down the port from which security violation is detected

 trap send snmp trap for security violaiton

Showing Duplex Options

wg_sw_a#sh interfaces

Ethernet 0/1 is Enabled

Hardware is Built-in 10Base-T Address is 0090.8673.3341 MTU 1500 bytes, BW 10000 Kbits 802.1d STP State: Forwarding Forward Transitions: 1 Port monitoring: Disabled Unknown unicast flooding: Enabled Unregistered multicast flooding: Enabled Description: Duplex setting: Half duplex

Back pressure: Disabled Receive Statistics Transmit Statistics - -

Total good frames 44841 Total frames 404502

Total octets 4944550 Total octets 29591574

Broadcast/multicast frames 31011 Broadcast/multicast frames 390913

Broadcast/multicast octets 3865029 Broadcast/multicast octets 28478154 Good frames forwarded 44832 Deferrals 0

Frames filtered 9 Single collisions 0

Runt frames 0 Multiple collisions 0

No buffer discards 0 Excessive collisions 0

Queue full discards 0

Errors: Errors: FCS errors 0 Late collisions 0

Alignment errors 0 Excessive deferrals 0

Giant frames 0 Jabber errors 0

Address violations 0 Other transmit errors 0

Duplex Mismatches

between connected ports

 The switch port is in autonegotiate and the

attached port is set to full duplex with no

auto-negotiation capability causing the switch port to

be in half-duplex mode

wg_sw_a#show interfaces

Ethernet 0/1 is Enabled

Hardware is Built-in 10Base-T

Address is 0090.8673.3341

MTU 1500 bytes, BW 10000 Kbits

802.1d STP State: Forwarding Forward Transitions: 1

Port monitoring: Disabled

Unknown unicast flooding: Enabled

Unregistered multicast flooding: Enabled

Description:

Duplex setting: Half duplex

Back pressure: Disabled

Receive Statistics Transmit Statistics

-Total good frames 44841 -Total frames 404502

Total octets 4944550 Total octets 29591574

Broadcast/multicast frames 31011 Broadcast/multicast frames 390913

Broadcast/multicast octets 3865029 Broadcast/multicast octets 28478154 Good frames forwarded 44832 Deferrals 0

Frames filtered 9 Single collisions 0

Runt frames 0 Multiple collisions 0

No buffer discards 0 Excessive collisions 0

Queue full discards 0

Errors: Errors: FCS errors 0 Late collisions 0

Alignment errors 0 Excessive deferrals 0

Giant frames 0 Jabber errors 0

FCS and Late Collision Errors

Managing Mac Address Table

wg_sw_a#sh mac-address-table

Number of permanent addresses : 0

Number of restricted static addresses : 0

Number of dynamic addresses : 6

-00E0.1E5D.AE2F Ethernet 0/2 Dynamic All

00D0.588F.B604 FastEthernet 0/26 Dynamic All

00E0.1E5D.AE2B FastEthernet 0/26 Dynamic All

0090.273B.87A4 FastEthernet 0/26 Dynamic All

00D0.588F.B600 FastEthernet 0/26 Dynamic All

00D0.5892.38C4 FastEthernet 0/27 Dynamic All

wg_sw_a#show mac-address-table

copy tftp://host/src_file nvram

wg_sw_a#copy nvram tftp://10.1.1.1/wgswd.cfg

Configuration upload is successfully completed

wg_sw_a#copy tftp://10.1.1.1/wgswd.cfg nvram

TFTP successfully downloaded configuration file

copy nvram tftp://host/dst_file

wg_sw_a#

wg_sw_a#

Managing Configuration File

To send the configuration to a TFTP server:

To download the configuration from a TFTP server:

Clear NVRAM

wg_sw_d#delete nvram

• Resets the system configuration to factory defaults.

 After completing this chapter, you should be able to

perform the following tasks:

 Describe Layer 2 switching (bridging) operations

 Describe the Catalyst 2950 switch operations

 Configure Catalyst 2950 switch

 Use show commands to verify Catalyst 1900 switch

configuration and operations