A Question-about UDLD.
udld setting udld setting
int f0/5 udld setting aggressive
What happens if interface f0/5 has been damaged?
A. Other interface will recover.
B. All links go down
C. link stays up
D. Reset interface
What happens if interface f0/5 has been damaged?
There is no good answers.
A. Other interface will recover. => Why? there is no auto recovery enabled here, and the agressive udld doesn’t impact the other interface, only the interface where it’s enable
B. All links go down => Same why all links? Only fa0/5 will go down, the other links of the switch will stay up.
C. link stays up => No the agressive mode will put the port in error disable
D. Reset interface => Same as answer C.
If I have this question on exam I will say B cause even if it’s a bad answers the other are worse…
@Debra
Where is the exhibit Diagram
This is incorrect the answer should be B: It will try to recover but until the problem is fixed they stay down.
What happens here is that Sw2 hears UDLD packets from Sw1 but Sw1 does not hear Sw2. That leads to Sw1 sending UDLD packets with an empty echo list. Sw2 expects to see itself in the echo list – and when it finds it empty, it assumes the link is faulty and brings it down. After 30 seconds, the process repeats.
the assumption that the state of port must move to Bidirectional before UDLD can do anything. That is not true, as you can see yourself. UDLD makes a series of checks before it declares a port to be Bidirectional, and failing those checks will cause the port to be err-disabled.