Configuring Dynamic CPCAR Adjustment for Protocol Packets

Context

If the default CPCAR settings cannot meet the changing requirements for the upper limit of the packet sending rate, the dynamic CPCAR adjustment function can meet these requirements.

If the default CIR value of a protocol has never been modified, a device with this function enabled can dynamically adjust the default CIR value for the protocol packets based on service scale (for example, number of dynamic ARP entries) and CPU usage to meet various service requirements. For details, see Table 1.

**Table 1** Default CPCAR adjustment for ARP packets
X = Number of ARP Entries	Adjusted CPCAR
X ≤ 512	Unchanged
512 < X ≤ 1024	128 kbit/s (remain unchanged if the default CIR is greater than 128 kbit/s)
1024 < X ≤ 3072	256 kbit/s
3072 < X ≤ 4096	512 kbit/s
X > 4096	512 kbit/s

**Table 2** Default CPCAR adjustment for VRRP packets
X = Number of VRRP Groups	Adjusted CPCAR
X ≤ 200	192 kbit/s
200 < X ≤ 300	256 kbit/s
300 < X ≤ 400	320 kbit/s
400 < X ≤ 500	384 kbit/s
500 < X ≤ 600	448 kbit/s
600 < X ≤ 1000	512 kbit/s

When the number of entries increases, the CPCAR value is dynamically increased. When the CPU usage is between 70% to 98%, the dynamic CPCAR adjustment stops. If the CPU usage is greater than 98%, the default CPCAR value is used.

The device dynamically adjusts the default CIR value of VRRP or ARP protocol packets only when the function is enabled globally and on VRRP or ARP protocol packets.

This function is only supported by S5720-EI, S5720-HI, S5720I-SI, S5720S-SI, S5720-SI, S5735-L, S5735S-L, S5735S-L-M, S5735-S, S5735S-S, S5735-S-I, S5730-HI, S5730S-EI, S5730-SI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720-LI, S6720S-EI, S6720S-LI, S6720S-SI, S6720-SI, S6730-H, S6730S-H, S6730-S, and S6730S-S.

Procedure

Run system-view
The system view is displayed.
Run cpu-defend dynamic-car enable
The dynamic CPCAR adjustment function is enabled globally for protocol packets.

By default, the dynamic CPCAR adjustment function is enabled globally.
Run cpu-defend dynamic-car [ arp | vrrp ] enable
The dynamic CPCAR adjustment function is enabled for ARP or VRRP.

By default, the dynamic CPCAR adjustment function is disabled for ARP or VRRP.