Cisco 642-902 Exam Braindumps 2014
The oldest switch in your network will become the core the root bridge so I mean it could be some little 10megabit per second switch that you forgot about sitting in a closet somewhere I thought you forgot unplugged and that that into becoming the rubric how is that all the center of the network let’s all go to that bridge to narrative of why did they do that well when they created the spanning tree protocol standard they say well you know you have a choice you can either go with the oldest one the lowest number or you can go with the Heisman like the newer faster switches and you know initially you and I made to the miracle white one in the pica to hire one the faster once it seems like it seems like that would be the better way to goal well the prom with Junes newer ones is then every single time you add a new switch to the network it's going to have a higher Mac address: and it causes a network disruption because everybody's a gold new room bridge in they start blocking and unblocking different links to find that were bridge right so by using the oldest Mac address by default they choose the stability route rather than the performance route I guess you could send cell with that being said what happens is all the all the switches switches elect to the root bridge he ends up winning everybody knows he wins because he has the lowest BPDU so he is the root all the switches light up one report the way they do that is by looking at what we called the port cost now cause I'll actually show a slight on that just a moment we’re each one of these links costs a certain amount like for instance a 100 megabits per second %uh is it cost up nineteen so let's just say all these just for grants are 100 megabits per second are cost nineteen they all see.