ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

VLANs 45
VLANs
Introduction
This chapter describes network design and topology considerations for using Virtual Local Area Networks
(VLANs). VLANs are commonly used to split up groups of network users into manageable broadcast domains, to
create logical segmentation of workgroups, and to enforce security policies among logical segments.
The following topics are discussed in this chapter:
• VLANs and Port VLAN ID Numbers
• VLAN Tagging
• VLANs and IP Interfaces
• VLAN Topologies and Design Considerations
NOTE: Basic VLANs can be configured during initial switch configuration.
More comprehensive VLAN configuration can be done from the command line interface. See the “VLAN
configuration” and “Port configuration” sections in the HP ProLiant BL p-Class GbE2 Interconnect Switch
Command Reference Guide.
Overview
Setting up VLANs is a way to segment networks to increase network flexibility without changing the physical
network topology. With network segmentation, each GbE2 Interconnect Switch port connects to a segment that is
a single broadcast domain. When a GbE2 Interconnect Switch port is configured to be a member of a VLAN, it
is added to a group of ports (workgroup) that belongs to one broadcast domain.
Ports are grouped into broadcast domains by assigning them to the same VLAN. Multicast, broadcast, and
unknown unicast frames are flooded only to ports in the same VLAN.
VLANs and port VLAN ID numbers
VLAN numbers
The GbE2 Interconnect Switch supports up to 1,000 VLANs per switch. Even though the maximum number of
VLANs supported at any given time is 1,000, each can be identified with any number between 1 and 4095.
VLAN 1 is the default VLAN, and all ports are assigned to it.
Viewing VLANs
The VLAN information menu (/info/l2/vlan) displays all configured VLANs and all member ports
that have an active link state, for example:
>> Layer 2# vlan
VLAN Name Status Ports
---- -------------------------------- ------ ----------------------
1 Default VLAN ena 1 4-22 24
2 VLAN 2 ena 2 3
4092 VLAN 4092 ena 23
PVID numbers
Each port in the GbE2 Interconnect Switch has a configurable default VLAN number, known as its PVID. This
places all ports on the same VLAN initially, although each port PVID is configurable to any VLAN number
between 1 and 4095.
The default configuration settings for GbE2 Interconnect Switches have all ports set as untagged members of
VLAN 1 with all ports configured as PVID = 1. In the default configuration example shown in the following figure,
all incoming packets are assigned to VLAN 1 by the default port VLAN identifier (PVID =1).