Reference Guide

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Virtual Link Trunking (VLT)
Virtual link trunking (VLT) is supported on the Dell Networking S5000 switch.
Virtual link trunking allows physical links between two chassis to appear as a single virtual link to the
network core or other switches such as Edge, Access, or top-of-rack (ToR). VLT reduces the role of the
spanning tree protocols by allowing link aggregation group (LAG) terminations on two separate
distribution or core switches, and by supporting a loop-free topology. (You still need a spanning tree
protocol to prevent the initial loop that may occur prior to VLT being established. After VLT is established,
you may use the rapid spanning treee protocol (RSTP) to prevent loops from forming with new links that
are incorrectly connected and outside the VLT domain.) VLT provides Layer 2 multipathing, creating
redundancy through increased bandwidth, and enabling multiple parallel paths between nodes and load-
balancing traffic where alternative paths exist.
Prerequisites: Before you configure VLT, make sure that both VLT peer switches are running the same
Dell Networking OS version and are configured for RSTP as described in the ”Virtual Link Trunking (VLT)”
chapter in the Dell Networking OS Configuration Guide.
CAUTION: Dell Networking recommends not enabling Stacking and VLT simultaneously. If you
enable both at the same time, unexpected behavior occurs.
back-up destination
Configure the IP address of the management interface on the remote VLT peer to be used as the
endpoint of the VLT backup link for sending out-of-band hello messages.
S5000
Syntax
back-up destination ip-address [interval seconds]
Parameters
ip-address Enter an IP address in dotted decimal format.
interval
seconds
Enter the keyword interval to specify the time interval
used to send hello messages. The range is 1 to 5 seconds.
Defaults 1 second
Command
Modes
VLT DOMAIN
Command
History
Version 9.0(1.3) Introduced on the S5000.
Virtual Link Trunking (VLT)
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