3Com CoreBuilder 3500, Implementation Manual

Page: 61 / 592

Key Guidelines for Implementation 61
Key Guidelines for
Implementation
To ensure that you understand the port numbering that the system
reports for certain aspects of your configuration (bridging information,
trunks, FDDI ports, and VLANs), observe these guidelines when you
configure your system:
■
Determine your physical port configuration before you attempt to
configure any bridging parameters.
Trunking
■
If you use trunking to group ports, configure your trunks before you
attempt to configure any VLANs. Be sure that you understand how
trunking associates a group of ports with a trunk. (See Chapter 8.)
These associations affect the following situations:
■
When you perform an operation for which you must specify bridge
ports (for example, when you define VLANs), you must use the
lowest-numbered port in each trunk to represent the trunk. The
operation that you perform then applies to all ports in the trunk.
■
When you view information that applies to more than one port (for
example, bridging displays for trunks), the port number field
identifies all ports in the trunk. A VLAN summary display lists all
physical ports to indicate which physical system connectors can
receive or transmit frames within a VLAN. (You must use the VLAN
detail display to see trunk port groups.)
FDDI DAS pairs
■
By default, FDDI ports are single-attached station (SAS) M-ports,
where each port is selectable as a bridge port. If you configure FDDI
ports as
dual-attach station (DAS) pairs , you associate two FDDI ports
with each DAS pair and only the lowest-numbered port in the pair is
selectable as a bridge port. Configure the appropriate number of DAS
pairs
before
you configure any VLANs. Be sure that you understand
how a DAS configuration associates the two FDDI ports in the pair.
(See Chapter 6.) These associations affect the following situations:
■
When you perform an operation for which you must specify bridge
ports (for example, when you define VLANs), you must use the
lowest-numbered port in each DAS pair to represent the DAS pair.
The operation that you perform then applies to both ports in the
DAS pair.
■
When you view information that applies to more than one port (for
example, bridging displays for DAS pairs), the port number field
identifies both ports in the DAS pair. A VLAN summary display lists
all physical ports to indicate which physical system connectors can
receive or transmit frames within a VLAN. (You must use the VLAN
detail display to see the DAS pairs.)