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
The following topics are discussed in this chapter:
VLANs and Port VLAN ID Numbers
VLANs and IP Interfaces
VLAN Topologies and Design Considerations
Basic VLANs can be configured during initial switch configuration.
More comprehensive VLAN configuration can be done from the command line interface. See the
HP 10Gb Ethernet BL-c Switch Command Reference Guide.
Setting up VLANs is a way to segment networks to increase network flexibility without changing the
physical network topology. With network segmentation, each switch port connects to a segment that is a
single broadcast domain. When a 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
The HP 10GbE 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. VLAN 4095 is reserved for switch
management, and it cannot be configured.