Planning and Implementing VLANs with HP-UX

Figure 4 VLAN Implementation Example
workstations servers
this link belongs
to more than
one VLAN
first tier of
switches that
support port-
based VLAN
and tagging
“backbone
switch” with
optional routing
module—
supports port-
based VLAN and
tagging
each of
these lines
indicates a
unique VLAN
A VLAN Implementation Example
This section provides an overview of how to implement an IP subnet-based VLAN in a network
with HP-UX. See Figure 4 for reference. The steps include the following:
• Identify the logical partitions in the network. That is, decide how many subnets you want
the network to be partitioned into, based on security, performance, and management
considerations. Assign VLAN IDs to each subnet.
• Assign subnets to each station in the network. Then configure VLANs on the switches and
the end stations as follows:
— Identify the number of ports needed and implement a monolithic switched LAN
infrastructure as shown in Figure 4. The switches must support port-based VLAN and
802.1Q-compliant tagging.
4
— Since workstations typically do not belong to more than one subnet, they can be VLAN
unaware. You must configure an untagged VLAN on the switch port a VLAN-unaware
workstation connects to. That means all frames received from the workstation will be
associated with the untagged VLAN. Furthermore, the switch will strip the VLAN tag
from all switch-to-end station traffic.
— Servers typically belong to more than one subnet. Therefore, configure the required
number of VLANs on the server NIC, each corresponding to a subnet. In this case, you
must configure both the HP-UX server and the switch port it attaches to. On the HP-UX
server, create VLANs (virtual interfaces) with appropriate VLAN IDs, and assign IP
4. Typically, in the factory configuration, all ports in the switch are configured with the same default untagged VLAN
of VLAN ID 1. This configuration allows a VLAN-aware switch to behave exactly like a traditional LAN switch.
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