Extreme Networks BlackDiamond 6800 Installation And User Manual page 46

Configuring the ATM Module
BlackDiamond switch. When a routed VLAN is configured, the total number of VLANs
supported in the BlackDiamond switch is 1500. If no routed VLANs are configured, and
you want to support more than 1500 VLANs, you must set the CPU transmit priority to
normal using the
config cpu-transmit-priority normal
Each ATM port can support the previously described VLAN limits, and the following
rules govern the association of PVCs with VLANs:
• Each PVC configured on a given ATM port must be associated with one or more
VLANs.
• The same VLAN cannot be associated with multiple PVCs on the same ATM port.
• Ports 1 and 2 on the same ATM module may not be bridged together; similarly, ports
3 and 4 on the same ATM module may not be bridged together. Ports 1 and 2 or
ports 3 and 4 may not be members of the same VLAN.
• Ports 1 and 2 on the same ATM module may not use the same VPI/VCI for a PVC;
similarly, ports 3 and 4 on the same ATM module may not use the same VPI/VCI
for a PVC.
• Both encapsulation types may be carried on the same PVC as long as they are
associated with different VLANs.
• Multiple tagged VLANs may be configured to use the L2 encapsulation on the same
PVC.
• Only one VLAN may be configured to use the IP encapsulation on a given PVC.
• Only one untagged VLAN may use the L2 encapsulation on a given PVC.
• When the IP encapsulation is configured, the ATM port must be the only member of
the associated VLAN, and the IP address of the peer router must be configured
using the
peer-ipaddress <ipaddress>
command.
Frames received on an ATM port for VLANs that the ATM port is not a member of are
discarded. Additionally, frames received from a PVC that contain a VLAN ID which
does not match the VLAN ID associated with any of the VLANs configured for that
PVC are discarded. Similarly, a frame received from the switch backplane is only
forwarded on a PVC when the VLAN ID in the frame matches the VLAN ID associated
with one of the VLANs configured for that PVC.
The ATM module supports all of the Spanning Tree Protocol (STP) commands. STP
Bridge Protocol Data Units (BPDUs) are sent on a PVC when an L2 encapsulated VLAN
associated with the PVC has been added to an STP domain. STP BPDUs are always
transmitted as untagged frames on ATM PVCs. The
3-4
command.
parameter in the
config atm add pvc
enable ignore-stp vlan
Asynchronous Transfer Mode (ATM) Module Installation and User Guide