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ND proxy includes common ND proxy and local ND proxy.
• Common ND proxy
As shown inFigure 59, VLAN-interface 1 with IPv6 address 4:1::99/64 and VLAN-interface 2 with
IPv6 address
4:2::99/64 belong to different subnets. Host A and Host B reside on the same
network but in different broadcast domains.
Figure 59 Application environment of ND proxy
Because Host A's IPv6 address is on the same subnet as Host B's, Host A directly sends an NS
message to obtain Host B's MAC address. However, Host B cannot receive the NS message
because they belong to different broadcast domains.
To solve this problem, enable common ND proxy on VLAN-interface 1 and VLAN-interface 2 of the
switch. The switch replies to the NS message from Host A, and forwards packets from other hosts
to Host B.
• Local ND proxy
As shown in Figure 60, both Host A and Host B belong to VLAN 2. Howev
er, they connect to
Ten-GigabitEthernet 1/1/7 and Ten-GigabitEthernet 1/1/5 respectively, which are isolated at
Layer 2.
Figure 60 Application environment of local ND proxy
Because Host A's IPv6 address is on the same subnet as Host B's, Host A directly sends an NS
message to obtain Host B's MAC address. However, Host B cannot receive the NS message
because they are isolated at Layer 2.
To solve this problem, enable local ND proxy on VLAN-interface 2 of Switch A so that Switch A
can forward messages between Host A and Host B.
Local ND proxy implements Layer 3 communication for two hosts in the following cases:
{ The two hosts must connect to different isolated Layer 2 ports of a VLAN.
{ If super VLAN is used, the two hosts must belong to different sub VLANs.
{ If Private VLAN is used, the two hosts must belong to different secondary VLANs.

Switch A
Switch B
XGE1/1/7
XGE1/1/5
XGE1/1/6
Host A
4:1::100/16
Host B
4:2::100/16
VLAN 2
Vlan-int2
4:3::100/16
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