Licensing Requirements and Limitations for ARP
Involved Network Elements
Other network elements are not required.
Licensing Requirements
ARP is a basic feature of a switch and is not under license control.
Feature Support in V200R019C10
All models of S2720, S5700, and S6700 series switches support ARP.
For details about software mappings, visit Hardware Query Tool and search for the desired product model.
Feature Limitations
Intra-VLAN proxy ARP and inter-VLAN proxy ARP determine whether VLAN information meets proxy requirements based on ARP entries matching source and destination IP addresses of packets. If no ARP entry matches the destination IP address of a packet, the switch broadcasts an ARP request in the VLAN (for intra-VLAN proxy ARP) or all sub-VLANs of the super-VLAN (for inter-VLAN proxy ARP) to learn the ARP entry matching the destination IP address. When multiple switches on a network have proxy ARP enabled and a requested destination IP address does not exist, this ARP broadcast packet triggers the same proxy process on other switches. This cyclic proxy process will cause a broadcast storm.
CPCAR limits the rate of protocol packets of different services sent to the control plane, ensuring security of the control plane. A switch can set the default CPCAR values for the packets of each protocol. The CPCAR values of some protocol packets need to be adjusted based on the actual service scale and user network. If the CPCAR values are adjusted improperly, network services are affected. To adjust the CPCAR values of ARP Request and Reply packets, contact technical support personnel.
- In V200R013C02 and later versions, after 1 to 1 VLAN mapping is configured, the VLANIF interface corresponding to the mapped VLAN supports dynamic ARP entry learning and ARP proxies. In addition, after 1 to 1 VLAN mapping is configured on the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-HI, S6730-H, S6730S-H, S6730-S, or S6730S-S, the VLANIF interface corresponding to the mapped VLAN supports the optimized ARP reply and fast ICMP reply functions.