Concept Guide
Enabling Null VLAN as the Default VLAN...................................................................................................................964
58 Virtual Link Trunking (VLT)...................................................................................................................... 965
Overview........................................................................................................................................................................ 965
VLT Terminology...................................................................................................................................................... 968
Layer-2 Trac in VLT Domains.............................................................................................................................. 969
Interspersed VLANs.................................................................................................................................................970
VLT on Core Switches.............................................................................................................................................970
Enhanced VLT........................................................................................................................................................... 971
Congure Virtual Link Trunking.................................................................................................................................... 972
Important Points to Remember..............................................................................................................................972
Conguration Notes.................................................................................................................................................973
Primary and Secondary VLT Peers........................................................................................................................ 976
RSTP and VLT.......................................................................................................................................................... 977
VLT Bandwidth Monitoring..................................................................................................................................... 977
VLT and Stacking..................................................................................................................................................... 977
VLT and IGMP Snooping.........................................................................................................................................977
VLT IPv6....................................................................................................................................................................978
VLT Port Delayed Restoration................................................................................................................................ 978
PIM-Sparse Mode Support on VLT....................................................................................................................... 978
VLT Routing .............................................................................................................................................................980
Non-VLT ARP Sync................................................................................................................................................. 983
RSTP Conguration.......................................................................................................................................................984
Preventing Forwarding Loops in a VLT Domain................................................................................................... 984
Sample RSTP conguration................................................................................................................................... 984
Conguring VLT....................................................................................................................................................... 985
PVST+ Conguration.................................................................................................................................................... 995
Sample PVST+ Conguration.................................................................................................................................996
Peer Routing Conguration Example..........................................................................................................................996
Dell-1 Switch Conguration.....................................................................................................................................997
Dell-2 Switch Conguration...................................................................................................................................1001
R1 Conguration.....................................................................................................................................................1004
Access Switch A1 Congurations and Verication.............................................................................................1005
eVLT Conguration Example...................................................................................................................................... 1006
eVLT Conguration Step Examples..................................................................................................................... 1006
PIM-Sparse Mode Conguration Example............................................................................................................... 1008
Verifying a VLT Conguration.....................................................................................................................................1009
Additional VLT Sample Congurations....................................................................................................................... 1012
Troubleshooting VLT..................................................................................................................................................... 1014
Reconguring Stacked Switches as VLT................................................................................................................... 1015
Specifying VLT Nodes in a PVLAN.............................................................................................................................1015
Association of VLTi as a Member of a PVLAN....................................................................................................1016
MAC Synchronization for VLT Nodes in a PVLAN............................................................................................. 1016
PVLAN Operations When One VLT Peer is Down.............................................................................................. 1017
PVLAN Operations When a VLT Peer is Restarted............................................................................................ 1017
Interoperation of VLT Nodes in a PVLAN with ARP Requests..........................................................................1017
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