This specifies the IPv6 ifindex of a interface to reach a DHCPv6 relay server, to which DHCPv6 messages received on this interface will be relayed. This parameter is only meaningful when the interface is in DHCPv6 relay mode.
Sources for this description
Netdisco MIB archive copiesNETGEAR official product and EOL MIB downloadsNETGEAR MIB copies (LibreNMS/Observium Community)