This question is simply a mental exercise I was running through. When I wasn't 100% sure of the answer I thought..."NetPro!"
(see attached pic)
Assume I have a stable STP tree, then I add gig link between SwitchC and SwitchD. My question revolves around exactly what SwitchC does once port 1/3 hits the learning state, bare with me hereâ¦.
From switch C's perspective:
The link between SwitchC and SwitchD is brought up.
Switch C generates a TCN towards the root bridge on the designated port. The designated switch (SwitchB) generates TCA to SwitchC and sends the TCN towards the root bridge on port 1/1. The root bridge receives the TCN and generates a configuration BPDU with the TCN bit set to all downstream switches. Switches that receive the config BPDU from the root bridge set their CAM table timeout to the value of forward_delay as advertised in the config BPDU.
At the same time all of this happening SwitchC has port 1/3 in the blocking state. Eventually port 1/3 will hit the learning state. Once it does hit the learning state it is going to receive a configuration BPDU from switch D with a root path cost of 8, which is less then SwitchC's current root port path cost.
How does SwitchC respond at this point? My gut is telling me that SwitchC immediately moves the current RP into the blocking state, and proceeds with moving port 1/3 through learning and eventually forwarding.
Uplinkfast on switch C would hold the new root port 1/3 in blocking state while keeping the old root port 1/1 forwarding for some 35 seconds in order to wait for port 1/2 on bridge D to go forwarding. Then it would switchover in one shot between the old root port and the new one.
RSTP/MST would switchover the root port immediately (putting 1/3 forwarding immediately) and then trigger a topology change to flush the cam tables. An agreement would be sent to port 1/2 on D so that it can go to forwading immediately.
Hi everyone, I would like to thank you in advance for any help you can provide a newcomer like myself!
Im studying the 100-105 book by Odom and am currently on the topic of Port security. I purchased a used 2960 and I'm trying to follow a...
While deploying a number of 18xx/2802/3802 model access points (APs), which run AP-COS as their operating platform. It can be observed on some occasions that while many of their access points were able to join the fabric WLC withou...
I am going to design and build an LAN network under a tunnel underground with long distance between the switches.
I will have 2 Catalyst switches and 8 Industrial IE3000, and they will be connected with fiber.
For now I am planning on use Layer-2 s...