Pvlan Operations When One Vlt Peer Is Down; Pvlan Operations When A Vlt Peer Is Restarted; Interoperation Of Vlt Nodes In A Pvlan With Arp Requests; Scenarios For Vlan Membership And Mac Synchronization With Vlt Nodes In Pvlan - Dell Force10 Z9000 Configuration Manual

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.

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):
780
Virtual Link Trunking (VLT)