Administrator Guide

Layer 2 Switching Commands 801
VLAN Commands
Dell Networking N1500/N2000/N3000/N4000 Series Switches
Dell Networking 802.1Q VLANs are an implementation of the Virtual Local
Area Network, specification 802.1Q. Operating at Layer 2 of the OSI model,
the VLAN is a means of parsing a single network into logical user groups or
organizations as if they physically resided on a dedicated LAN segment of
their own. In reality, this virtually defined community may have individual
members scattered across a large, extended LAN. The VLAN identifier is part
of the 802.1Q tag, which is added to an Ethernet frame by an Q-compliant
switch or router. Devices recognizing 802.1Q-tagged frames maintain
appropriate tables to track VLANs. The first three bits of the 802.1Q tag are
used by 802.1p to establish priority for the packet.
Dell Networking switches supports 802.1Q VLANs. As such, ports may
simultaneously belong to multiple VLANs. VLANs allow a network to be
logically segmented without regard to the physical locations of devices in the
network.
Dell Networking switches supports up to 4093 VLANs for forwarding.
Interfaces can be configured in trunk mode (multiple VLAN support) or
access mode (single VLAN support).
VLANs can be allocated by subnet and netmask pairs, thus allowing
overlapping subnets. For example, subnet 10.10.128.0 with Mask
255.255.128.0 and subnet 10.10.0.0 with Mask 255.255.0.0 can have different
VLAN associations.
Access, trunk and general mode VLAN configurations are maintained
independently by the switch and take affect when the interface is configured
in the relevant mode. In other words, trunk mode VLAN configuration only
affects an interface when it is configured in trunk mode. When the interface
is configured in trunk mode, access and general mode VLAN configuration is
ignored.
2CSNXXX_SWUM204.book Page 801 Monday, January 25, 2016 1:25 PM