Users Guide
LAGs, you can associate the same port channel or LAG bundle that is a part of a VLT to a PVLAN by using the interface interface
and switchport mode private-vlan commands.
When a VLTi port in trunk mode is a member of symmetric VLT PVLANs, the PVLAN packets are forwarded only if the PVLAN settings of
both the VLT nodes are identical. You can configure the VLTi in trunk mode to be a member of non-VLT PVLANs if the VLTi is configured
on both the peers. MAC address synchronization 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 or promiscuous mode.
• You can configure a VLT LAG or port channel to be in trunk, access, or promiscuous port modes when 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 normal VLAN or a PVLAN. If you configure a VLT LAG to be a promiscuous port, you can configure that
LAG to be a member of PVLAN only. If you configure a VLT LAG to be in access port mode, you can add that 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 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 any
one 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 secondary
VLANs, similar to the behavior for normal trunk ports. VLAN parity is not validated if you associate an ICL to a PVLAN. Similarly, if you
dissociate an ICL from a PVLAN, although the PVLAN parity exists, ICL is removed from that PVLAN.
Association of VLTi as a Member of a PVLAN
If 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
as a 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 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)
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