Configuring the Optimized ND Reply Function
Context
When a switch functions as an access gateway, it receives a large number of ND Request packets that request the switch to reply with its local interface MAC address. If all these ND Request packets are sent to the CPU, the CPU usage of the MPU increases, and other services are affected.
The optimized ND reply function addresses this issue. After this function is enabled, the LPU receiving an ND Request packet returns an ND Reply packet if the ND Request packet is destined for a local interface on the switch, and discards the ND Request packet if the packet is not destined for a local interface on the switch. The optimized ND reply function is applicable to the switch with multiple LPUs configured.
- If the corresponding ND entry exists and the packet information is the same as the saved ND entry information, the LPU receiving the ND Request packet performs optimized ND reply to this ND Request packet.
- If the corresponding ND entry exists but the packet information differs from the saved ND entry information, the LPU receiving the ND Request packet does not perform optimized ND reply to this ND Request packet.
- If the corresponding ND entry does not exist, the LPU receiving the ND Request packet does not perform optimized ND reply to this ND Request packet.
Procedure
Run system-view
The system view is displayed.
Run undo nd optimized-reply disable
The optimized ND reply function is enabled.
By default, the optimized ND reply function is enabled.
- The optimized ND reply function takes effect for ND Request packets sent by wireless users.
- The optimized ND reply function takes effect for ND Request packets received on VLANIF interfaces and VBDIF interfaces enabled with IPv6. VLANIF interfaces of Group VLANs and Separate VLANs in MUX VLANs, VLANIF interfaces of mapped VLANs, and VLANIF interfaces of super-VLANs do not perform optimized ND reply.
- If the number of global unicast IPv6 addresses on a VLANIF interface or VBDIF interface enabled with IPv6 exceeds 1, the switch does not perform optimized ND reply for NS packets received on this interface.
- If the ND snooping function is enabled on a switch, the switch does not perform optimized ND reply to received ND Request packets on the corresponding LPU.
- The switch does not perform optimized ND reply to the following received packets:
- NS packets with the source IPv6 address :: (that is, Duplicate Address Detection packets)
- Packets with IPv6 extension headers