- Extra headers would be required when the frame size of packets is reduced, which increases the traffic volume.

- One EX2300 the bandwidth calculation for incoming traffic on these platforms includes both packet data and packet headers.

- The traffic rate may exceed the policer bandwidth-limit and burst-size-limit due to the extra headers (which is being considered for the calculating the traffic rate in the policer), leading to packet drops.

- The policer configuration for these platforms should account for the extra header traffic.

For Example

Policer:

set firewall family ethernet-switching filter 200M term T1 then count 200m

set firewall family ethernet-switching filter 200M term T1 then policer 200m

set firewall policer 200m if-exceeding bandwidth-limit 200m

set firewall policer 200m if-exceeding burst-size-limit 10k

set firewall policer 200m then discard

Policer applied at 200m with rate 190mbps is sent from traffic generator.

1) For Frame size 64

To calculate No. of frames being send from traffic generator per sec = 190000000/(64*8)

= 371094 fps

Additional 20bytes IFG is added on each frame = 371094 *(64+20)*8

=249,375,168 bps

249,375,168 bps => Which is greater than 200m limit configured. Hence we see the drops.

2) For frame size 1000

To calculate No. of frames being send from spirent per sec = 190000000/(1000*8)

= 23750 fps

With additional 20 bytes IFG to each frame = 23750 * (1000+20)*8

= 193,800,000 bps

193,800,000 bps => which is lesser than 200m configured and hence we don't see drops with higher frame size.

This is an expected behaviour on this platform. The policer configuration for these platforms should account for the extra header traffic.

2024-01-19 : Article Created

2026-10-29 : Updated