Multiple Ip Interfaces Per Vlan; Ip Interface Setup - D-Link xStack DES-6500 User Manual

Multiple IP Interfaces Per VLAN

Multiple IP interfaces per VLAN 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. The multiple IP interfaces per VLAN function means the Swith 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 multiple IP interfaces per VLAN, 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.
Multiple IP interfaces per VLAN is a valuable tool for network administrators requiring a multitude of IP addresses, but
configuring the Switch for Multiple IP interfaces per VLAN 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.
•

IP Interface Setup

Each VLAN must be configured prior to setting up the VLAN's corresponding IP interface.
An example is presented below:
In this case, six IP interfaces are required, so a CIDR notation of 10.32.0.0/11 (or a 11-bit) addressing scheme will work.
This addressing scheme will give a subnet mask of 11111111.11100000.00000000.00000000 (binary) or 255.224.0.0
(decimal).
xStack DES-6500 Modular Layer 3 Chassis Ethernet Switch User Manual
Application Limitation: A multicast router cannot be connected to IP
interfaces that are utilizing the Multiple IP interfaces per VLAN function.
NOTE: Only the primary IP interface will support the BOOTP relay agent.
VLAN Name
System (default)
Engineer
Marketing
Finance
Sales
Backbone
Table 6- 4. VLAN Example - Assigned Ports
VID Switch Ports
1 5, 6, 7, 8, 21, 22, 23, 24
2 9, 10, 11, 12
3 13, 14, 15, 16
4 17, 18, 19, 20
5 1, 2, 3, 4
6 25, 26
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