Assigning Ip Addresses - D-Link DGS-3600 Series User Manual

Duplicate Address Detection (DAD)
DAD messages are used to specify that there is more than one node on a local link possessing the same IP address. IPv6 addresses
are only leased for a defined period of time. When that time expires, the address will become invalid and another address must be
addressed to the node. To ensure that this new address is unique on the local link, a node runs a DAD process to determine the
uniqueness of the new address. This is done through the use of a Neighbor Solicitation message containing a Tentative address.
This message will detect if another node on the local link has this Tentative address. If the Tentative address is found on another
node, that node will send out a Neighbor Advertisement message, the process will be terminated, and manual configuration will be
necessary. If no answer is forthcoming regarding this Neighbor Solicitation message containing the tentative address, the address
is allotted to the node and connectivity is established.

Assigning IP Addresses

For IPv4 addresses, users may only assign one address per interface and only one address may be used on a particular VLAN. Yet,
IPv6 addresses are different. All IPv6 interfaces on the switch must have at least one IPv6 link-local unicast address, if the user is
employing the IPv6 addressing scheme. Multiple IPv6 addresses may be configured for IPv6 interfaces, regardless of type,
whether it is unicast, multicast or anycast. The scope of the address has some bearing on the assigning multiple addresses to a
single interface as well. If multiple physical interfaces are considered as one interface on the Internet layer, multiple unicast
addresses may be allotted to multiple physical interfaces, which would be beneficial for load sharing on these interfaces. This is
dependent on these unicast addresses having a scope smaller than the link-local address, if these unicast addresses are not the
source or destination address for IPv6 packets to or from address that are not IPv6 neighbors of the interface in question.
IP Multinetting
IP Multinetting is a function that allows multiple IP interfaces to be assigned to the same VLAN. This is beneficial to the
administrator when the number of IPs on the original interface is insufficient and the network administrator wishes not to resize
the interface. IP Multinetting is capable of assigning another IP interface on the same VLAN without affecting the original
stations or settings of the original interface.
Two types of interfaces are configured for IP multinetting, primary and secondary, and every IP interface must be classified as one
of these. A primary interface refers to the first interface created on a VLAN, with no exceptions. All other interfaces created will
be regarded as secondary only, and can only be created once a primary interface has been configured. There may be five interfaces
per VLAN (one primary, and up to four secondary) and they are, in most cases, independent of each other. Primary interfaces
cannot be deleted if the VLAN contains a secondary interface. Once the user creates multiple interfaces for a specified VLAN
(primary and secondary), that set IP interface cannot be changed to another VLAN.
IP Multinetting is a valuable tool for network administrators requiring a multitude of IP addresses, but configuring the Switch for
IP multinetting may cause troubleshooting and bandwidth problems, and should not be used as a long term solution. Problems
may include:
•
The Switch may use extra resources to process packets for multiple IP interfaces.
•
The amount of broadcast data, such as RIP update packets and PIM hello packets, will be increased.
xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch
Application Limitation: A multicast router cannot be connected to IP
interfaces that are utilizing the IP Multinetting function.
NOTE: Only the primary IP interface will support the BOOTP relay agent.
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