Administrator Guide

verifying the PVLAN parity on both the peers. In such a case, if a PVLAN is present as a VLT 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 that VLAN. Whenever a change in the VLAN mode on one of the peers occurs, the information is
synchronized with the other peer and VLTi is either 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 is identical on both the peers, VLTi is configured as a member of those VLANs. This
behavior is because of security functionalities in a PVLAN. 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 part of that VLAN.
MAC Synchronization for VLT Nodes in a PVLAN
For 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 and the primary to secondary association of the VLT
nodes is determined on both the VLT peers. MAC synchronization is performed for the VLT 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 are learned on that VLT LAG are synchronized between the peers only if the PVLAN
mode on both the peers is identical. For example, if the MAC 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 on the validation mechanism that is initiated for MAC synchronization of VLT peers,
MAC addresses learned on a particular VLAN are either synchronized with the other peers, or MAC addresses
synchronized from the other peers on the same VLAN are deleted. This method of processing 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 of the VLTi link in a VLAN and the VLT LAG mode.
PVLAN Operations When One VLT Peer is Down
When 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. All the PVLAN MAC entries that correspond to the operationally down VLT LAG are
maintained as synchronized entries in the device. These MAC entries are removed when the peer VLT LAG
also becomes inactive or a change in PVLAN configuration occurs.
Virtual Link Trunking (VLT) 991