Trouble Ticket 6 VLAN and Spanning Tree

Just as loops can occur in the upper layers because of mutual redistribution and improper filtering, they can also occur at Layer 2. Back in Chapters 6 and 7 I spent some time on the Spanning Tree Protocol (STP). STP assists with bridge/switch loops and it is normally not the best practice to just turn it off. As a matter of fact, Cisco performs a per-VLAN STP. VLANs help you segment your broadcast domains and use a lesser number of routers while doing so. Howevec, the ideal design is stMn hierarchical in nature.

In this Trouble Ticket, you are just starting to implement VLANs and are thinking about upgrading your 1900 switch. For now, knappsnarrows and hostb are both in the default VLAN 1, which requ ires no configuration on the 1900 on your part except for management IP addressing.

To prepare for Trouble Ticket 6 you need to make a minor physical change to the topology by shutting do wn the e0/0 interface on the osprey router and port 12 on the knappsnarrows switch. Alternatively, just remove the cable between them. Two additional connections are required between kentnarrows and knappsnarrows as shown in Figure 10-9.

Figure 10-9. Trouble Ticket 10-6 VLANs and STP

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Figure 10-9. Trouble Ticket 10-6 VLANs and STP

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Start your testing from hos tea to work toward any major issu es. When you can successfully^ telnet to kentnarrows, chesapeakebay, and knappsnarrows from hosta, hostb, and hostc, that is definitely an accomplishment. You have finished the labs when you can console directly into the devices and copy the configurations to the TFTP server.

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