VLAN or Virtual LAN

VLANs are literally virtual LANs. A LAN can be defined as a network connecting devices inside a single building or inside the buildings close to each other. Typically, LANs are used to isolate broadcast domains for better performance and manageability. VLAN technology, on the other hand, allows us to separate the logical connectivity from physical connectivity. Users are still connected via the normal physical cable connections, but the connectivity is viewed from the station or application perspective, and no longer limited to the boundaries of the physical network topology. A VLAN may also be thought of as a single switched LAN infrastructure segmented into logical partitions based on certain traffic attributes such as IP subnet, MAC address, application, protocol, etc.

HP -UX VLAN is, therefore, a virtual networking technology which is based on the IEEE 802.1Q/p standards. It is a host-based software solution applicable to end-stations as opposed to switch-based VLANs. With HP-UX VLAN, the end stations determine the VLAN association of each Ethernet frame, and convey it to a switch (or other link partners) via the VLAN tag, thereby relieving switches of the burden of snooping into each inbound frame in determining a VLAN association. Features of VLAN:

HP-UX VLANs are implemented with host-based IEEE 802.1Q/p compliant tagging to allow configuring multiple VLANs on a given Ethernet LAN card, based on their IP-subnet, protocol, or LAN card port.
HP-UX VLANs are for use over Fast Ethernet or Gigabit Ethernet LAN cards running HP-UX 11i PA-RISC-based servers and workstations. Up to 1024 VLANs are supported per LAN card port.
HP-UX VLANs do not require you to rewrite applications, install new hardware, or re-cable. They are also compatible with HP MC/ServiceGuard as well as HP's Online Addition and Replacement (OLAR) capabilities.
Physically dispersed workgroups can be logically connected within the same broadcast domain to appear as if they were on the same physical LAN.
A single physical link can simultaneously serve several IP subnets when subnet-based VLANs are configured on that link.
Workgroups requiring increased security can be logically connected within the same broadcast domain. Broadcast traffic will be isolated within the secure group.
End-stations using VLANs can offer rudimentary class of service (CoS) locally by prioritizing traffic for certain activities.

Refer to the manual Using HP VLANs for further information on installation and administration of this free software.

VLAN or Virtual LAN

Technical documentation

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