ccna exam fees 200 301

ccna exam fees 200 301.The minimum overhead value to reach the root bridge. The sender's minimum bridge ID.The sender's minimum port ID.Receiver's minimum port IDoIn Figure 14-2, the cost for switch S3 to reach the root bridge from port FaO/21 is 19,and the cost to reach the root bridge from port FaO/22 is 19+19=38, so port FaO/21 on switch S3 is the root port. Similarly switch S2 has a cost of 19 to reach the root bridge from port FaO/23 and a cost of 19+19=38 to reach the root bridge from port FaO/21, so port FaO/23 on switch S2 is the root port.Sometimes it is not possible to determine the root port by comparing the overhead values to reach the root bridge. Example to determine the root port is shown in Figure 14.3, in this figure, S1 is the root bridge, at this time, the overhead value of the 2 links of S2 to reach the root bridge are both 19, so continue to compare the sender whose bridge ID is the smallest, because the BPDUs are sent by S1, so they are also the same, continue to compare the sender whose port ID is the smallest, suppose the FaO/2 port ID of S1 is 128.2, the port ID of FaO/1 The port ID of FaO/1 is 128.1, the comparison is finally divided into winners and losers, and the port ID of switch S2 is 128.1.FaO/2 is the root port, and the corresponding FaO/1 port is blocked. 32769:AA-AA-AA-AA-AA-AA 32769:Root Bridge 3. Electing Designated and Non-Designated PortsOnce the switch has determined the root port, it must also determine the remaining ports as either designated or non-designated ports to complete the creation of a logical loop-free spanning tree. Each segment in a switched network can have only one designated port. When the switch end of the 2 non-root ports32769: Figure 14-2 Example of STP Convergence Process Figure 14.3 Example of Determining the Root PortChapter 14 STP and Switch Stacking .221 .