Dell C1048P Port Extender Networking Command-Line Reference Guide for the C900 - Page 2042

61 Virtual Link Trunking (VLT) Virtual link trunking (VLT) allows physical links between two chassis to appear as a single virtual link to the network core. VLT eliminates the requirement for Spanning Tree protocols by allowing link aggregation group (LAG) terminations on two separate distribution or core switches, and by supporting a loop-free topology. 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. NOTE: When you launch the VLT link, the VLT peer-ship is not established if any of the following is TRUE: • The VLT System-MAC configured on both the VLT peers do not match. • The VLT Unit-Id configured on both the VLT peers are identical. • The VLT System-MAC or Unit-Id is configured only on one of the VLT peers. • The VLT domain ID is not the same on both peers. If the VLT peer-ship is already established, changing the System-MAC or Unit-Id does not cause VLT peer-ship to go down. Also, if the VLT peer-ship is already established and the VLT Unit-Id or System-MAC are configured on both peers, then changing the CLI configurations on the VLT Unit-Id or System-MAC is rejected. When the VLT peer-ship is already established, you can remove the VLT Unit-Id or System-MAC configuration from either or both peers. However, removing configuration settings can cause the VLT ports to go down. back-up destination Configure the IPv4 or IPv6 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. C9000 Series Syntax Parameters back-up destination {[ipv4-address] | [ipv6 ipv6-address] [interval seconds]} ipv4-address ipv6 Enter the IPv4 address of the backup destination. Enter the keyword ipv6 then an IPv6 address in the X:X:X:X::X format. 2042 Virtual Link Trunking (VLT)