Reference Guide

• 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, VLT
assigns the primary node role to the node with the highest MAC address.
• In a VLT domain, the peer network devices must run the same OS10 software version.
• Congure the same VLT domain ID on peer devices. If a VLT domain ID mismatch occurs on VLT peers, the VLT Interconnect (VLTi)
does not activate.
• To verify VLAN and VLT-VLAN LAG mismatch errors, use the show vlt id mismatch command on each VLT peer.
• In a VLT domain, VLT peers support connections to network devices that are connected to only one peer.
• To start conguring a VLT domain, enter the vlt-domain domain-id command in CONFIGURATION mode.
VLT interconnect
A VLT interconnect (VLTi) is the link used to synchronize states between VLT peers. OS10 automatically adds VLTi ports to VLANs spanned
across VLT peers. VLTi ports are not supported as members of VLANs congured on only one peer.
• The system automatically provisions the required VLANs.
• VLAN ID 4094 is reserved as an internal control VLAN for the VLT domain, and it is not user congurable.
• VLT peer switches operate as separate nodes with independent control and data planes for devices attached to non-VLT ports.
• The VLTi synchronizes L2 and L3 control-plane information across the two nodes. The VLTi is used for data trac only when there is a
link failure that requires using VLTi for data packets to reach their nal destination.
• Trac with an unknown destination MAC address, multicast, or broadcast trac can cause ooding across the VLTi.
• MAC, ARP, IPv6 neighbors that are learned over VLANs across VLT peer nodes are synchronized across the nodes.
• In a VLT domain, LLDP, ow control, port monitoring, and jumbo frame features are supported on a VLTi.
• Use the discovery-interface command in VLT-DOMAIN mode to congure member interfaces of the VLTi.
Congure VLT
Verify that both VLT peer devices are running the same software version. For VRRP operation, congure VRRP groups and L3 routing on
each VLT peer. To congure VLT and create a VLT domain where two devices are physically connected and are used to provide single port-
channel connection to access devices, congure settings on each VLT peer device.
1 To prevent loops in VLT domain, enable spanning tree protocol globally (spanning-tree mode rstp command). Only RSTP
mode is supported on VLT ports.
2 Create a VLT domain by conguring the same domain ID on each peer (vlt-domain command).
3 Congure the VLT interconnect interfaces on each peer (discovery-interface command). After you congure both sides of
the VLTi, the primary and secondary roles in the VLT domain are automatically assigned.
4 (Optional) Manually recongure the default VLT MAC address.
5 Congure VLT port-channels between VLT peers and an attached device (vlt-port-channel command). Assign the same VLT
port-channel ID (1 to 1024) to interfaces on dierent peers that you bundle together so that peer interfaces appear as a single VLT
LAG to downstream devices.
6 Connect peer devices in a VLT domain to an attached access device or server.
Virtual link trunking
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