Description

ARP learning speed is different between learning 5000 MACs and 250 MACs under the same traffic speed.

5000 MACs = 250 MACs/VLAN x 20 VLANs
250 MACs = 1 VLAN
Note: 250 MACs situation occurred when switching routes to allow traffic go from the other side

Solution

By default, the maximum token in a bucket is 25. One token is required for every ARP resolution requests. If there are no free tokens, then the ARP resolution request is discarded. The token refill rate is one token every 15 minutes. The ARP resolution is limited to about 60-90/seconds by this feature. However, a token bucket is created per logical interface, and the ARP resolution rate may vary depending on the configuration.

Token bucket configuration is static and can not be changed through configuration. However, token bucket refill rate can be changed in a line card shell.

set nhdb resolve-interval
set nhdb resolve-max-token

The command updates default values and all new next-hops are programmed with the new token bucket parameters. Existing next-hops are not updated.