Dell EMC SmartFabric OS10 User Guide Release 10.5.0

VLAN Scaling

When VLANs are created, traffic class is specified for each VLAN that maps the VLAN traffic to a specific queue on the egress port. Class-maps are created for each VLAN matching and the action is specified in the policymap that maps it to a specific traffic class. Using traffic class-to-queue mapping, the traffic gets mapped to the corresponding queue.

Since ACL rules are created on a per VLAN basis, the scale of VLANs is dependent on the number of ACL rules available. The ACL space is also shared by other applications such as FCoE. When more VLANs are created, the L2 QoS ACL space for the VLAN ACLs get exhausted. If the VLAN ACL creation fails, it results in VLAN creation failure. As a result, there cannot be more than 256 VLANs in Fabric mode.

classmap type qos  CM100
match vlan 100

policymap type qos PM_VLAN
class CM100
set qos-group 4 

Any addition, deletion, or modification to the VLAN or the traffic class happens within the same policymap.

In the NPU, each classmap maps to an ACL entry in the L2QOS region matching the vlanid in the classmap.

Constraints

VLAN scaling is limited to the Fabric mode.

Currently Dynamic ARP Inspection (DAI) uses the vlan-group id. NAS implicitly programs the VLAN-group id in the Vlan table. But DAI feature is not enabled in Fabric mode.

Use of vlan-group id is limited only to applications which require grouping for the purpose of using ACLs.