Chassis and Power Supplies
Managing MAC Addresses on the Switch
OmniSwitch 7700/7800 Hardware Users Guide
April 2005
page 2-41
VLAN Router Ports and MAC Address Allocation
The sections below cover MAC address allocation for all new VLAN router ports configured on the
switch. MAC address allocation is dictated by the type of MAC router mode that is currently operational
on the switch. The two MAC router modes are
multiple MAC router mode
and
single MAC router mode
.
Note.
Regardless of which MAC router mode is operating, the switch’s default VLAN 1 always uses the
base chassis MAC address. Also, each VLAN can be assigned two concurrent router port types, IP and
IPX. If both router port types are assigned to a VLAN, they will share the same MAC address.
Multiple MAC Router Mode
By default, each VLAN router port is assigned a unique MAC address. This default function is referred to
as
multiple MAC router mode
. Multiple MAC router mode provides important compatibility with
Alcatel’s Omni Switch/Router (OmniS/R) products. If you have OmniS/R products in your network and
are using VLAN router ports on your switch, multiple MAC router mode should remain enabled.
In multiple MAC router mode, MAC addresses are allocated sequentially from EEPROM, starting from
the
third
address in the default range.
Reminder.
The first, second, and last MAC addresses are allocated to the chassis, 802.1X, and the EMP,
respectively. This leaves a total of 29 MAC addresses (MAC range index numbers 3 through 31) avail-
able to VLAN router ports.
Enabling Single MAC Router Mode
When multiple MAC router mode is disabled, all VLAN router ports configured on the switch use the base
chassis MAC address as an identifier. This is also referred to as
single MAC router mode
.
Single MAC router mode helps preserve MAC addresses on the switch. However, this non-default func-
tion does not provide important compatibility with Alcatel’s Omni Switch/Router (OmniS/R) products.
You cannot enable single MAC router mode via the CLI
. To enable single MAC router mode, you must
add the following command syntax to the
boot.cfg
file:
vlan router mac multiple disable
After adding the command syntax to the
boot.cfg
file and saving your changes, reboot the switch.
When the switch boots, the system software reads from the
boot.cfg
file. All valid command syntax,
including
vlan router mac multiple disable
, is initialized and single MAC router mode is enabled.
Because the syntax has been added to the switch’s
boot.cfg
file, single MAC router mode will remain
enabled after subsequent switch reboots.
