200 301 questions

200 301 questions.FaO/23 Gi0/l Gi0/2 .' Desg FWD 19 Altn BLK 30 Root FWD 4 128.23 128.25 128.26 P2p P2p P2p33 Chapter 2 Configuring Spanning Tree Protocol (STP )Configuring Priority to Influence Root Selection Another larger configuration option is to make an impact on the election of the root switch by changing the switch's priority. The priority can be set using the spanning-tree vlan vlan-id priority global configuration command. this command also sets the basic priority of the switch (that is. this command takes a multiple of 4096 as an argument.) Nonetheless, Cisco also provides us with a better way to configure specific priority values as opposed to configuring them. In most designs, the network administrator will choose two switches as the root switch: one of them will be the root switch when all switches are running, and the second will replace the first as the root switch when the first one fails. Use the spanning tree vlan vlan-id root primary and spanning-tree vlan vlan-id root secondary commands to enable the switch IOS to support this mode of operation. The spanning-tree vlan vlan-id rootprimary command tells the switch to set its priority as low as possible in order to become the root switch immediately. The switch looks at the current root in the VLAN and the priority of the root. The local switch then selects the priority value that will enable the local switch to become the root switch. Remember that the Cisco switch uses a default base priority of 32768,This command will follow the following approach when selecting the base priority. /gjH If the current root's base priority is higher than 24576, the local switch uses the base priority of 24576. k.SS If the current root's base priority is 24576 or lower, then the local switch sets its base priority to the highest multiple of 4096, which still enables the local switch to become the root switch. To have a switch take over as the root switch when another switch fails, use the spanning-tree vlan vlan-id root secondary command. This command is very similar to the spanning-tree vlan vlan-id root primary command, and while it does not have the same priority value as that previous primary switch, it is better than all other switches. This command sets the switch's base priority to 28672 regardless of the current root's current priority value. for example. in Figure 2Y and Figure 2-5. with SW1 as the root switch. as shown. a base priority of 32768 is used by default for all three switches when a different command is used. The configuration required to be able to make SW2 the primary root switch and SW1 the standby root switch is shown in Example 2-5. the purpose is simply to show the transition between the two roles. These commands would set SW2's base priority to 24576 and SW1's base priority to 28672.Example 2-5 Making SW2 the Basic Root Switch and SW1 the Secondary Root Switch SW2# configure terminal Enter configuration commands, one per line. end with CNTL/Z. SW2(config)# japanning-tree vlan 10 root primary SW2(config)# AZNext, SW1 is configured to be the primary. Next, SW1 is configured to back-up SW1 SW1# configure terminal Enter configuration commands, one per line. end with CNTL/Z. SW1(conf ig)# spanning-tree vlan 10 root secondary SW1(config)# AZ SW1#The next command shows the local switch's name. The next command shows the local switch's BID (SW1) SW1# show spanning-tree vlan 10 bridgeVlan Example 2-5 (continued) VLAN0010 Bridge ID 28682 (28672, 10) 1833.9d7b.0e80 Hello Max Fwd Time Age Dly Protocol2 20 15 ieeeThe next command shows the root1s network. The next command shows the root1s BID (SW2)