Cisco Networking Training (CCENT/CCT/CCNA R&S) - · PDF file© 2013 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 1 Cisco Networking Training (CCENT/CCT/CCNA

Cisco Confidential© 2013 Cisco and/or its affiliates. All rights reserved. 1

Cisco NetworkingTraining (CCENT/CCT/CCNA R&S)Rick Rowe - GDT

Ron Giannetti - Cisco

© 2013 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2

• Review

Hubs/Bridges/Switches

• Device Access

• VLANs

VTP

Configuration

• Trunks

DTP

Configuration

• Troubleshooting/CDP


• Hubs

• Bridges

• Half Duplex / Full Duplex

• Collision Domains














• MAC Addresses (Unicast vs Broadcast)

• CAM Table, MAC Address Table, Bridging Table, Switching Table

• Forwarding

• Loop Prevention (STP)

• Processing (Store and Forward, Cut Through, Fragment Free)




• A LAN includes all devices in the same broadcast domain

To reduce CPU overhead on each device by reducing the number of devices that receive each broadcast frame

To reduce security risks by reducing the number of hosts that receive copies of frames that the switches flood (broadcasts, multicasts, and unknown unicasts)

To improve security for hosts that send sensitive data by keeping those hosts on a separate VLAN

To create more flexible designs that group users by department, or by groups that work together, instead of by physical location

To solve problems more quickly, because the failure domain for many problems is the same set of devices as those in the same broadcast domain

To reduce the workload for the Spanning Tree Protocol (STP) by limiting a VLAN to a single access switch


• Moving Data Between VLANs (hint.. Layer 2 switches won’t)


• Creating VLANs and Assigning VLANs to interfaces

SW1# configure terminalEnter configuration commands, one per line. End with CNTL/Z.SW1(config)# vlan 2 SW1(config-vlan)# name Freds-vlanSW1(config-vlan)# exitSW1(config)# interface range fastethernet 0/13 - 14SW1(config-if)# switchport access vlan 2 SW1(config-if)# end


• Cisco Proprietary

• Used to Share VLANs between Cisco Switches

• 3 Modes

Server

Client

Transparent

• Use Transparent to not have to “deal” with VTP

• If you play with VTP, make sure and note the config revision

• Highest config revision will win (might bring down your network!)


• Multiswitch VLAN with Trunking

The use of trunking allows switches to pass frames from multiple VLANs over a single physical connection by adding a small header to the Ethernet frame.

• 802.1Q defines one special VLAN ID as the Native VLAN


• Static or Dynamic Trunking?

Static = easy and deterministic

Dynamic = Flexibility/Many options

switchport mode trunk

Type of Trunk? 802.1Q or ISL

switchport trunk encapsulation {dot1q | isl | negotiate}

Administrative Mode – always trunk, always not trunk, or negotiate


• Allowed VLAN list provides you with a way to disable VLANs from a trunk

switchport trunk allowed vlan {add | all | except | remove} vlan-list


• Etherchannel, PortChannel, and Channel-group are synonymous

• Manual configuration is the simplest

Step 1. Add the channel-group number mode on interface subcommand under each physical interface that should be in the channel.

Step 2. Use the same number for all commands on the same switch, but the channel-group number on the neighboring switch can differ.


• Dynamic EtherChannels

(2) Different protocols can be used

Port Aggregation Protocol (PAgP) – Cisco proprietary

Link Aggregation Control Protocol (LACP) – IEEE standard

Both accomplish the same thing – dynamically form a channel and settings

Both require one side to begin negotiations


• Troubleshooting

1. On the local switch, all the channel-group commands for all the physical interfaces must use the same channel-group number.

2. The channel-group number can be different on the neighboring switches.

3. If using the on keyword, you must use it on the corresponding interfaces of both switches.

4. If you use the desirable keyword on one switch, the switch uses PAgP; the other switch must use either desirable or auto.

5. If you use the active keyword on one switch, the switch uses LACP; the other switch must use either active or passive.


• Troubleshooting

The list of items the switch checks includes the following:

■ Speed

■ Duplex

■ Operational access or trunking state (all must be access, or all must be trunks)

■ If an access port, the access VLAN

■ If a trunk port, the allowed VLAN list (per the switchport trunk allowed command)

■ If a trunk port, the native VLAN

■ STP interface settings

• In addition, other switch settings are checked as well

PAgP and LACP for dynamic, and CDP for manual

All settings must be the same except for STP interface settings


• Cisco Discovery Protocol (CDP)

Proprietary Cisco protocol discovers basic information about neighbor Cisco devices

• Link Layer Discovery Protocol (LLDP) IEEE standard

Serves same role as CDP

• CDP used to troubleshoot, confirm, fix network diagrams

Good to verify cabling before troubleshooting assumed flow of traffic

• A lot of information is shown through CDP – Disable on links not connected to Cisco devices

Thank you.

Documents

Cisco Networking Training (CCENT/CCT/CCNA R&S) - · PDF file© 2013 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 1 Cisco Networking Training (CCENT/CCT/CCNA