Tài liệu Etherchannel LAN Switching Troubleshooting pdf

1-5 Semester 8 Internetwork Troubleshooting 1.0 - Lab 5.2.9 Copyright  2001, Cisco Systems, Inc.

Lab 5.2.9 Etherchannel LAN Switching Troubleshooting

2/3 Fast0/1

Fa 0/12

FastEthernet

Crossover

Connection ALSwitch

10.8.1.1/24

2900XL-Ent

4006 L3

Client

10.8.1.3/24

2/4 Fast0/2

Objective

The primary function of the spanning-tree algorithm (STA) is to cut loops cre￾ated by redundant links in bridged networks. The Spanning-Tree Protocol

(STP) operates at Layer2 of the OSI model and, by the means of bridge proto￾col data units (BPDUs) exchanged between bridges, elects the ports that will

eventually forward or block traffic. This protocol can fail in some specific cases

and troubleshooting the resulting situation can be very difficult, depending on

the design of the network. The most important part of troubleshooting is done

before the problem occurs.

For this exercise, utilize a systematic approach to troubleshooting Etherchannel

Switch network.

Scenario

This network is not part of the International Travel Agency.

As the Enterprise Network Administrator, you have a small, switched network

with all clients existing in the same VLAN. There are currently no fault tolerant

links in your network. You have several hosts communicating to each other be￾tween the distribution layer and access layer switches at 100MB full duplex.

Your network administrator feels performance would improve if a second

100MB link between the distribution layer switches and the access layer

switches were added. Your network administrator adds a new crossover cable

between DLSwitch and ALSwitch and reports that communications between

both switches has stopped, however, the rest of the network continues to oper￾ate. DLSwitch indicates the following message:

“STP loop - channel 2/3-4 is disabled in vlan 1”

You must investigate the Spanning-Tree configuration and Port-Channels to

ensure proper configuration.