hi guys-
been playing with BFD in our N7K lab to deploy through our DCs.
In testing I am observing the different timers with Echo mode vs asymmetic mode.
I setup non-echo/asymm mode for our L3 port channels so i could enable 'bfd per-link' as is recommended by cisco. These timers by default are 50ms hello, 3x multiplier (150ms holdtime)
I also setup default echo mode on a single 10g link from 7k to 7k, default slower echo timers are 6000ms hold, 2000ms hellos. I even tried adjusting the timers on the interface to 50ms/150ms but it doesnt change when I do "show bfd nei details" (output: Holdown (hits): 6000 ms (0), Hello (hits): 2000 ms (134))
I did some reading online but I still have 1 question I can't seem to verify---- why would you ever want to run echo mode with the much slower timers of 6 seconds for a deadtimer when BFD is all about subsecond failure detection?
I also noticed this--- the packets are coming faster than 2000ms usually... so I'm confused
n7k2(config-if)# show bfd neighbors details | i Count
Rx Count: 2322, Rx Interval (ms) min/max/avg: 22/1731/630 last: 1129 ms ago
Tx Count: 2244, Tx Interval (ms) min/max/avg: 1883/1883/1883 last: 898 ms ago
n7k1:
interface Ethernet1/17
ip eigrp 90 bfd
bfd interval 50 min_rx 50 multiplier 3
n7k2:
interface Ethernet1/4
ip eigrp 90 bfd
bfd interval 50 min_rx 50 multiplier 3