Specifying VLT Nodes in a PVLANYou can configure VLT peer nodes in a private VLAN (PVLAN). VLT enables redundancy without theimplementation of Spanning Tree Protocol (STP), and provides a loop-free network with optimalbandwidth utilization.Because the VLT LAG interfaces are terminated on two different nodes, PVLAN configuration of VLTVLANs and VLT LAGs are symmetrical and identical on both the VLT peers. PVLANs provide Layer 2isolation between ports within the same VLAN. A PVLAN partitions a traditional VLAN into sub-domainsidentified by a primary and secondary VLAN pair. With VLT being a Layer 2 redundancy mechanism,support for configuration of VLT nodes in a PVLAN enables Layer 2 security functionalities. To achievemaximum VLT resiliency, you should configure the PVLAN IDs and mappings to be identical on both theVLT peer nodes.The association of PVLAN with the VLT LAG must also be identical. After the VLT LAG is configured to bea member of either the primary or secondary PVLAN (which is associated with the primary), ICL becomesan automatic member of that PVLAN on both switches. This association helps the PVLAN data flowreceived on one VLT peer for a VLT LAG to be transmitted on that VLT LAG from the peer.You can associate either a VLT VLAN or a VLT LAG to a PVLAN. First configure the VLT interconnect (VLTi)or a VLT LAG by using the peer-link port-channel id-number command or the VLT VLAN by usingthe peer-link port-channel id-number peer-down-vlan vlan interface number commandand the switchport command. After you specify the VLTi link and VLT LAGs, you can associate thesame port channel or LAG bundle that is a part of a VLT to a PVLAN by using the interface interfaceand switchport mode private-vlan commands.When a VLTi port in trunk mode is a member of symmetric VLT PVLANs, the PVLAN packets areforwarded only if the PVLAN settings of both the VLT nodes are identical. You can configure the VLTi intrunk mode to be a member of non-VLT PVLANs if the VLTi is configured on both the peers. MAC addresssynchronization is performed for VLT PVLANs across peers in a VLT domain.Keep the following points in mind when you configure VLT nodes in a PVLAN:• Configure the VLTi link to be in trunk mode. Do not configure the VLTi link to be in access orpromiscuous mode.• You can configure a VLT LAG or port channel to be in trunk, access, or promiscuous port modeswhen you include the VLT LAG in a PVLAN. The VLT LAG settings must be the same on both the peers.If you configure a VLT LAG as a trunk port, you can associate that LAG to be a member of a normalVLAN or a PVLAN. If you configure a VLT LAG to be a promiscuous port, you can configure that LAGto be a member of PVLAN only. If you configure a VLT LAG to be in access port mode, you can addthat LAG to be a member of the secondary VLAN only.• ARP entries are synchronized even when a mismatch occurs in the PVLAN mode of a VLT LAG.Any VLAN that contains at least one VLT port as a member is treated as a VLT VLAN. You can configure aVLT VLAN to be a primary, secondary, or a normal VLAN. However, the VLT VLAN configuration must besymmetrical across peers. If the VLT LAG is tagged to any one of the primary or secondary VLANs of aPVLAN, then both the primary and secondary VLANs are considered as VLT VLANs.If you add an ICL or VLTi link as a member of a primary VLAN, the ICL becomes a part of the primaryVLAN and its associated secondary VLANs, similar to the behavior for normal trunk ports. VLAN parity isVirtual Link Trunking (VLT) 887
