Reference Guide

PVLAN Operations When a VLT Peer is Restarted
When the VLT peer node is rebooted, the VLAN membership of the VLTi link is preserved and when the
peer node comes back online, a verification is performed with the newly received PVLAN configuration
from the peer. If any differences are identified, the VLTi link is either added or removed from the VLAN.
When the peer node restarts and returns online, all the PVLAN configurations are exchanged across the
peers. Based on the information received from the peer, a bulk synchronization of MAC addresses that
belong to spanned PVLANs is performed.
During the booting phase or when the ICL link attempts to come up, a system logging message is
recorded if VLT PVLAN mismatches, PVLAN mode mismatches, PVLAN association mismatches, or PVLAN
port mode mismatches occur. Also, you can view these discrepancies if any occur by using the show
vlt mismatch command.
Interoperation of VLT Nodes in a PVLAN with ARP Requests
When an ARP request is received, and the following conditions are applicable, the IP stack performs
certain operations.
• The VLAN on which the ARP request is received is a secondary VLAN (community or isolated VLAN).
• Layer 3 communication between secondary VLANs in a private VLAN is enabled by using the ip
local-proxy-arp command in INTERFACE VLAN configuration mode.
• The ARP request is not received on the ICL
Under such conditions, the IP stack performs the following operations:
• The ARP reply is sent with the MAC address of the primary VLAN.
• The ARP request packet originates on the primary VLAN for the intended destination IP address.
The ARP request received on ICLs are not proxied, even if they are received with a secondary VLAN tag.
This behavior change occurs because the node from which the ARP request was forwarded would have
replied with its MAC address, and the current node discards the ARP request.
Scenarios for VLAN Membership and MAC Synchronization With VLT Nodes
in PVLAN
The following table illustrates the association of the VLTi link and PVLANs, and the MAC synchronization
of VLT nodes in a PVLAN (for various modes of operations of the VLT peers):
Table 73. VLAN Membership and MAC Synchronization With VLT Nodes in PVLAN
VLT LAG Mode PVLAN Mode of VLT VLAN ICL VLAN
Membership
Mac
Synchronization
Peer1 Peer2 Peer1 Peer2
Trunk Trunk Primary Primary Yes Yes
Trunk Trunk Primary Normal No No
Trunk Trunk Normal Normal Yes Yes
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Virtual Link Trunking (VLT)