Spotting “The Churn”
2 – Take a prefix from #1 and do “show ip bgp x.x.x.x | include best #“ for a little over 1 minute. If you see a pattern in the best path transition then this prefix is churning. If not, select another prefix from #1 and try again.
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Then, the best path changes to #14.
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #14)
Next, the best path changes to #18.
Router#show ip bgp 3.8.6.0 | include best #
Paths: (24 available, best #18)
Now, the best path is #17 again.
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Router#show ip bgp 3.8.6.0 | include best #
Paths: (23 available, best #17)
Notice the transition “17-ᡉ-ᡆ-ᡊ-ᡉ-ᡉ”!!
Repeat Step #2 for another minute just to be sure