Nortel business policy switch 2000, User Manual

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128 Chapter 2 Network configuration
208700-C
VLAN configuration rules
VLANs operate according to specific configuration rules. When creating VLANs,
consider the following rules that determine how the configured VLAN reacts in
any network topology:
• You must be in the Pure BPS 2000 Stack mode and using software version 1.2
to be able to configure between 65 and 256 VLANs. (You can configure up to
64 VLANs in Hybrid mode.)
• 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.
• If a port is a trunk group member, all trunk members are added or deleted
from the VLAN.
• All ports involved in trunking and port mirroring must have the same VLAN
configuration. If a port is on a trunk with a mirroring port, the VLAN
configuration cannot be changed.
• VLANs are not dependent on Rate Limiting settings.
• If a port is an IGMP member on any VLAN, and is removed from a VLAN,
the port’s IGMP membership is also removed.
• If a port is added to a different VLAN, and it is already configured as a static
router port, the port is configured as an IGMP member on that specific
VLAN.
For more information about configuring VLANs, refer to Chapter 1 for additional
guidelines on configuring VLANs and spanning tree groups and Chapter 3.
See also the Appendixes for configuration flowcharts that can help you use this
feature.
IGMP snooping
Business Policy Switches can sense Internet Group Management Protocol (IGMP)
host membership reports from attached stations and use this information to set up
a dedicated path between the requesting station and a local IP Multicast router.
After the pathway is established, the Business Policy Switch blocks the IP