Reference Guide

VLT physical ports 802.1p, 802.1q, LLDP, ow control, port monitoring, and jumbo frames are supported on VLT physical ports.
System
management
protocols
All system management protocols are supported on VLT ports — SNMP, RMON, AAA, ACL, DNS, FTP, SSH,
syslog, NTP, RADIUS, SCP, and LLDP.
L3 VLAN
connectivity
Enable L3 VLAN connectivity (VLANs assigned with an IP address) on VLT peers by conguring a VLAN interface
for the same VLAN on both devices.
Optimized
forwarding with
VRRP
To enable optimized L3 forwarding over VLT, use VRRP Active-Active mode. VRRP Active-Active mode enables
each peer to locally forward L3, resulting in reduced trac ow between peers over the VLTi.
Spanning-tree
protocol
Only RSTP mode is supported on VLT ports.
NOTE: 802.1x, DHCP snooping, MSTP, RPVST+,ingress and egress QoS are not supported on VLT ports.
Terminology
Discovery interface Port interfaces on VLT peers in the VLT interconnect (VLTi) link.
Virtual-link trunk
(VLT port-channel)
A combined port-channel between an attached device and VLT peer switches.
VLT domain The domain includes VLT peer devices, VLT interconnect, and all port-channels in the VLT connected to the
attached devices. It is also associated with the conguration mode that you must use to assign VLT global
parameters.
VLT interconnect
(VLTi)
The link between VLT peer switches used to synchronize operating states.
VLT MAC address (Optional) Unique MAC address that you assign to the VLT domain. A VLT MAC address is the common address
used for all VLT peers. If you do not congure a VLT MAC address, the MAC address of the primary peer is used as
the VLT MAC address across all peers.
VLT peer device A pair of devices connected using a dedicated port-channel — the VLTi.
VLT port-channel ID Groups port-channel interfaces on VLT peers into a single virtual-link trunk connected to an attached device.
Assign the same port-channel ID to interfaces on dierent peers that you bundle together.
VLT peer switches have independent management planes. A VLTi between the VLT chassis maintains synchronization of L2/L3 control
planes across the two peer switches.
VLT domain
A VLT domain includes the VLT peer devices, VLT interconnect, and all port-channels in the VLT that connect to the attached devices. It is
also associated with the conguration mode that you must use to assign VLT global parameters.
• A VLT domain supports two node members. These peer devices appear as a single logical device to network access devices that
connect to VLT ports through a port-channel.
• A VLT domain consists of the two core nodes, interconnect trunk, and LAG members that connect to attached devices.
• Each VLT domain has a unique MAC address that you create or the VLT creates automatically.
• VLAN ID 4094 is reserved as an internal control VLAN for the VLT domain.
• ARP, IPv6 neighbors, and MAC tables synchronize between the VLT peer nodes.
• VLT peer devices operate as a separate node with independent control and data planes for devices that attach to non-VLT ports.
• One node in the VLT domain takes a primary role and the other node takes the secondary role. In a VLT domain with two nodes, the
VLT assigns the primary node role to the node with the highest MAC address.
Virtual link trunking
523