I am trying to understand the definition of "input" and "output" traffic to an interface.
Below is extracted from Flexible NetFlow Documentation in Cisco 3850 ->
If you apply a flow monitor in the input direction:
• Use the match keyword and use the input interface as a key field.
• Use the collect keyword and use the output interface as a collect field. This field will be present in the exported records but with a value of 0.• If you apply a flow monitor in the output direction:
• Use the match keyword and use the output interface as a key field.
• Use the collect keyword and use the input interface as a collect field. This field will be present in the exported records but with a value of 0.
- When traffic ingresses into
Gi1/0/1
and needs to egress out ofgi1/0/2
, is that traffic considered as "input" or "output" togi1/0/2
? - I can't twist my head around on why, if I apply a flow in the input
direction, I have to collect output interface, and that field will
be value
0
?