• 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 a VLT VLAN to be a primary,secondary, or a normal VLAN. However, the VLT VLAN configuration must be symmetrical across peers. If the VLT LAG is tagged to anyone of the primary or secondary VLANs of a PVLAN, 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 primary VLAN and its associated secondaryVLANs, similar to the behavior for normal trunk ports. VLAN parity is not validated if you associate an ICL to a PVLAN. Similarly, if youdissociate an ICL from a PVLAN, although the PVLAN parity exists, ICL is removed from that PVLAN.Association of VLTi as a Member of a PVLANIf a VLAN is configured as a non-VLT VLAN on both the peers, the VLTi link is made a member of that VLAN if the VLTi link is configured asa PVLAN or normal VLAN on both the peers. If a PVLAN is configured as a VLT VLAN on one peer and a non-VLT VLAN on another peer,the VLTi is added as a member of that VLAN by verifying the PVLAN parity on both the peers. In such a case, if a PVLAN is present as aVLT PVLAN on at least one of the peers, then symmetric configuration of the PVLAN is validated to cause the VLTi to be a member of thatVLAN. Whenever a change in the VLAN mode on one of the peers occurs, the information is synchronized with the other peer and VLTi iseither added or removed from the VLAN based on the validation of the VLAN parity.For VLT VLANs, the association between primary VLAN and secondary VLANs is examined on both the peers. Only if the association isidentical on both the peers, VLTi is configured as a member of those VLANs. This behavior is because of security functionalities in aPVLAN. For example, if a VLAN is a primary VLT VLAN on one peer and not a primary VLT VLAN on the other peer, VLTi is not made a partof that VLAN.MAC Synchronization for VLT Nodes in a PVLANFor the MAC addresses that are learned on non-VLT ports, MAC address synchronization is performed with the other peer if the VLTi (ICL)link is part of the same VLAN as the non-VLT port. For MAC addresses that are learned on VLT ports, the VLT LAG mode of operation andthe primary to secondary association of the VLT nodes is determined on both the VLT peers. MAC synchronization is performed for theVLT LAGs only if the VLT LAG and primary-secondary VLT peer mapping are symmetrical.The PVLAN mode of VLT LAGs on one peer is validated against the PVLAN mode of VLT LAGs on the other peer. MAC addresses that arelearned on that VLT LAG are synchronized between the peers only if the PVLAN mode on both the peers is identical. For example, if theMAC address is learned on a VLT LAG and the VLAN is a primary VLT VLAN on one peer and not a primary VLT VLAN on the other peer,MAC synchronization does not occur.Whenever a change occurs in the VLAN mode of one of the peers, this modification is synchronized with the other peers. Depending onthe validation mechanism that is initiated for MAC synchronization of VLT peers, MAC addresses learned on a particular VLAN are eithersynchronized with the other peers, or MAC addresses synchronized from the other peers on the same VLAN are deleted. This method ofprocessing occurs when the PVLAN mode of VLT LAGs is modified.Because the VLTi link is only a member of symmetric VLT PVLANs, MAC synchronization takes place directly based on the membership ofthe VLTi link in a VLAN and the VLT LAG mode.PVLAN Operations When One VLT Peer is DownWhen a VLT port moves to the Admin or Operationally Down state on only one of the VLT nodes, the VLT Lag is still considered to be up. Allthe PVLAN MAC entries that correspond to the operationally down VLT LAG are maintained as synchronized entries in the device. TheseMAC entries are removed when the peer VLT LAG also becomes inactive or a change in PVLAN configuration occurs.Virtual Link Trunking (VLT) 909
