Switch User Manual

20 An Introduction to IP Routing Protocols
Management VLAN
Prior to Software Release 4.0, the Management VLAN was the only VLAN
that was used to carry the management traffic, including Telnet, Web,
SNMP, BootP and TFTP for the switch. The Management VLAN always
exists on the switch and cannot be removed. All IP settings, including switch
IP address, stack IP address, subnet mask and default gateway, apply only
to the Management VLAN.
In this release of Nortel Ethernet Routing Switch 5500 Series, a regular
Layer 2 (L2) VLAN behaves like a routable L3 VLAN if a pair of IP addresses
and a MAC address are attached to the VLAN. When routing is enabled in
L3 mode, every L3 VLAN is capable of doing routing as well as carrying the
management traffic. Any L3 VLAN can be used instead of the Management
VLAN to manage the switch.
Layer 2 versus Layer 3 mode
When the Nortel Ethernet Routing Switch 5500 Series is configured to route
IP traffic between different VLANs, the switch is considered to be running in
L3 mode; otherwise, the switch runs in L2 mode.
The L3 manager determines in which mode a switch or a stack should be
run. The mode is determined based on the user settings and events. But
the general rule is to select:
•
L3 mode: if routing is turned on globally for the switch or stack.
•
L2 mode: if routing is turned off globally for the switch or stack.
Routing and management
In L3 mode, the Management VLAN, as well as all other L3 VLANs, has the
capability to route and carry the management traffic. In this release of the
Nortel Ethernet Routing Switch 5500 Series, the settings apply to all L3
VLANs or only to the Management VLAN. "VLAN settings" (page 20)shows
all possible settings and default settings for each type of VLAN.
VLAN settings
VLAN/Feature
Routing
(default)
Management
(Routing)
Default Route
Management VLAN
(L2 mode)
Off On Yes (Management
VLAN only)
Management VLAN
(L3 mode)
On/off (on) On No
L3 VLAN On/off (on) On/off (on) Yes (global)
Setting IP routing
To set IP routing (or L3 VLANs), take the following steps:
Nortel Ethernet Routing Switch 5500 Series
Configuration-IP Routing Protocols
NN47200-503 03.01 Standard
5.1 27 August 2007
Copyright © 2005-2007, Nortel Networks
.