ccna worth it 2019

ccna worth it 2019.After selecting the root port, each switch will determine whether its port connected to each network segment should be the designated port. As mentioned earlier, the network segments designated port is responsible for carrying traffic between that segment and the rest of the Layer 2 network. Of course, the network segment itself has no knowledge of the process of selecting the designatedport process-this is done by the switch.chooses the designated port by first checking the cumulative path overhead to the root switch for each switch connected to the segment. If theC 10 root switch switch 3 0001.0000./C1Dsegment is connected to two switches, the switch with the lowest cumulative path overhead will be the designated switch for that segment, and its port connected to that segment will be the designated port.Returning to our network example, let's start with the simplest network segments - B and C. In LAN segment B, switch 1 has a cumulative path cost of 0, switch 2 is 20, and switch 5 is 10. o Since the root switch (switch 1) has the lowest cumulative path overhead, its port J is the designated port for LAN segment B. The same is true for LAN segment C: the root switch has the lowest cumulative path overhead (0), so switch 1's port I is the LAN segment C.LAN segment A has two options: port D on switch 3 and port H on switch 4. Switch 3 has a lower cumulative path overhead (10, while switch 4 has a cumulative path overhead of 50), so port D on switch 3 is the designated port for LAN segment A.In terms of designated ports, there are also two options for LAN segment D: port B on switch 5 and port G on switch 4. switch 5 has a cumulative path overhead of 10, while switch 4 has a path overhead of 30, so port B on switch 5 is the designated port for LAN segment D.Figure 13.9 shows the updated STP topology for this network, where DP denotes the designated port of the LAN segment.