ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

VLANs 49
VLANs and IP interfaces
Carefully consider how you create VLANs within the GbE2 Interconnect Switch, so that communication with the
GbE2 Interconnect Switch remains possible. In order to access the GbE2 Interconnect Switch for remote
configuration, trap messages, and other management functions, make sure that at least one IP interface on the
GbE2 Interconnect Switch has a VLAN defined.
You can also inadvertently cut off access to management functions if you exclude the ports from the VLAN
membership. For example, if all IP interfaces are left on VLAN 1 (the default), and all ports are configured for
VLAN 2, then GbE2 Interconnect Switch management features are effectively cut off.
To remedy this, keep all ports used for remote GbE2 Interconnect Switch management on the default VLAN and
assign an IP interface to the default VLAN.
For more information on configuring IP interfaces, see the “Configuring an IP interface” section in the “Accessing
the GbE2 Interconnect Switch” chapter.
VLAN topologies and design considerations
By default, all GbE2 Interconnect Switch ports are configured to the default VLAN 1. This configuration groups all
ports into the same broadcast domain. The VLAN has an 802.1Q VLAN ID of 1. VLAN tagging is turned off,
because by default all ports are members of a single VLAN only.
If configuring Spanning Tree Protocol (/cfg/l2/stp), note that each of spanning tree groups 2-16 may contain
only one VLAN. If configuring Multiple Spanning Tree Protocol (/cfg/l2/mrst), each of spanning tree groups
1-16 may contain multiple VLANs.
VLAN configuration rules
VLANs operate according to specific configuration rules which must be considered when creating VLANs. For
example:
• HP recommends that all ports involved in trunking and Port Mirroring have the same VLAN configuration. If
a port is on a trunk with a mirroring port, the VLAN configuration cannot be changed. For more information
on port trunking, see the “Port Trunking example” section in the “Ports and trunking” chapter.
• All ports that are involved in Port Mirroring must have memberships in the same VLANs. If a port is
configured for Port Mirroring, the port’s VLAN membership cannot be changed. For more information on
configuring Port Mirroring, see the “Port Mirroring” section in the “Troubleshooting tools” appendix.
• When you delete a VLAN, untagged ports are moved to the default VLAN (VLAN 1). Tagged ports that
belong only to the deleted VLAN are moved to the VLAN identified by the PVID. Tagged ports that belong
to multiple VLANs are removed from the deleted VLAN only.
Multiple VLANS with tagging
The following figure shows only those switch port to server links that must be configured for the example. While
not shown, all other server links remain set at their default settings.