Proxy Arp Capability On Vlt Peer Nodes - Dell Z9500 Configuration Manual

switchport mode private-vlan {host | promiscuous | trunk}
• host (isolated or community VLAN port)
• promiscuous (intra-VLAN communication port)
• trunk (inter-switch PVLAN hub port)
5 Access INTERFACE VLAN mode for the VLAN to which you want to assign the PVLAN interfaces.
CONFIGURATION mode
interface vlan vlan-id
6 Enable the VLAN.
INTERFACE VLAN mode
no shutdown
7 To obtain maximum VLT resiliency, configure the PVLAN IDs and mappings to be identical on both the VLT peer nodes. Set
the PVLAN mode of the selected VLAN to primary.
INTERFACE VLAN mode
private-vlan mode primary
8 Map secondary VLANs to the selected primary VLAN.
INTERFACE VLAN mode
private-vlan mapping secondary-vlan vlan-list
The list of secondary VLANs can be:
• Specified in comma-delimited (VLAN-ID,VLAN-ID) or hyphenated-range format (VLAN-ID-VLAN-ID).
• Specified with this command even before they have been created.
• Amended by specifying the new secondary VLAN to be added to the list.

Proxy ARP Capability on VLT Peer Nodes

The proxy ARP functionality is supported on VLT peer nodes.
A proxy ARP-enabled device answers the ARP requests that are destined for another host or router. The local host forwards the
traffic to the proxy ARP-enabled device, which in turn transmits the packets to the destination.
By default, proxy ARP is enabled. To disable proxy ARP, use the no proxy-arp command in Interface mode. To re-enable
proxy ARP, use the ip proxy-arp command in Interface mode. To view if proxy ARP is enabled on the interface, use the show
config command in INTERFACE mode. If it is not listed in the show config command output, it is enabled. Only nondefault
information displays in the show config command output.
An ARP proxy operation is performed on the VLT peer node IP address when the peer VLT node is down. The ARP proxy stops
working either when the peer routing timer expires or when the peer VLT node goes up. Layer 3 VLT provides a higher
resiliency at the Layer 3 forwarding level. VLT peer routing allows you to replace VRRP with routed VLT to route the traffic from
Layer 2 access nodes. With proxy ARP, hosts can resolve the MAC address of the VLT node even when VLT node is down.
If the ICL link is down when a VLT node receives an ARP request for the IP address of the VLT peer, owing to LAG-level hashing
algorithm in the top-of-rack (ToR) switch, the incorrect VLT node responds to the ARP request with the peer MAC address.
Proxy ARP is not performed when the ICL link is up and the ARP request the wrong VLT peer. In this case, ARP requests are
tunneled to the VLT peer.
Proxy ARP supported on both VLT interfaces and non-VLT interfaces. Proxy ARP is supported on symmetric VLANs only. Proxy
ARP is enabled by default. To support proxy ARP, the routing table must be symmetrically configured. For example, consider a
sample topology in which you configure VLAN 100 on two VLT nodes, node 1 and node 2. You did not configure the ICL link
between the two VLT nodes. Assume that the VLAN 100 IP address in node 1 is 10.1.1.1/24 and VLAN 100 IP address in node 2 is
20.1.1.2/24. In this case, if the ARP request for 20.1.1.1 reaches node 1, node 1 does not perform the ARP request for 20.1.1.2.
Proxy ARP is supported only for the IP address that belongs to the received interface IP network. Proxy ARP is not supported if
Virtual Link Trunking (VLT) 909