Introduction to LACP in VMware by Broadcom
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Introduction to LACP in VMware by Broadcom

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Article ID: 389732

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Updated On: 03-04-2025

Products

VMware vCenter Server

Issue/Introduction

This document has general information regarding the use of LACP on a physical switch with a vSphere Distributed Switch. 

Environment

VMware vCenter Server

Resolution

Topology for LAG to LACP configuration:

VMware supports Link Aggregation Control Protocol (LACP) on vSphere Distributed Switch (VDS) only and LACP can only be configured through the vSphere Web Client.

  • LACP is a standards-based method to control the bundling of several physical network links together to form a logical channel for increased bandwidth and redundancy purposes. LACP enables a network device to negotiate an automatic bundling of links by sending LACP packets to the peer.
  • LACP works by sending frames down all links that have the protocol enabled. If it finds a device on the other end of the link that also has LACP enabled, it also sends frames independently along the same links, enabling the two units to detect multiple links between themselves and then combine them into a single logical link.
  • Enhanced LACP support allows you to connect ESXi hosts to physical switches that use dynamic link aggregation.
    • Multiple Link Aggregation Groups (LAGs) can now be created on a single Distributed Switch to aggregate the available bandwidth of physical NICs connecting to LACP port channels.
    • When you create a LAG on a vSphere Distributed Switch (vDS), up to 24 LAG ports can be associated to it.
    • These LAG ports are similar in concept to dvUplink ports, which are essentially slots that are associated with actual physical uplinks on each of the ESXi hosts.
      • For example, in a two port LAG, the LAG ports have names similar to Lag1-0 and Lag1-1. Each ESXi host will have vmnics configured for each of these LAG ports.
    • Each LAG can be configured for either Active or Passive LACP modes.
      • In an Active LACP LAG, all ports are in an active negotiating state. The LAG ports initiate negotiations with the LACP port channel on the physical switch by sending LACP packets.
      • In Passive mode, the ports respond to LACPDUs they receive but do not initiate the LACP negotiation.
      • If the physical switch is configured for active negotiating mode, it can be left in Passive Mode.
      • If LACP needs to be enabled and Active mode is unavailable, it is highly possible that the Physical Switch is not configured for LACP.

vSphere LACP supports these load balancing types:

  • Destination IP address
  • Destination IP address and TCP/UDP port
  • Destination IP address and VLAN
  • Destination IP address, TCP/UDP port and VLAN
  • Destination MAC address
  • Destination TCP/UDP port
  • Source IP address
  • Source IP address and TCP/UDP port
  • Source IP address and VLAN
  • Source IP address, TCP/UDP port and VLAN
  • Source MAC address
  • Source TCP/UDP port
  • Source and destination IP address
  • Source and destination IP address and TCP/UDP port
  • Source and destination IP address and VLAN
  • Source and destination IP address, TCP/UDP port and VLAN
  • Source and destination MAC address
  • Source and destination TCP/UDP port
  • Source port ID
  • VLAN

Note: These policies are configured for LAG. The LAG load balancing policies always override any individual Distributed Port group if it uses the LAG. 

LACP limitations on a vSphere Distributed Switch

  • The LACP is not supported with software iSCSI port binding. iSCSI multipathing over LAG is supported, if port binding is not used.
  • LACP settings do not exist in host profiles.
  • LACP between two nested ESXi hosts is not possible.
  • You can create up to 64 LAGs on a distributed switch. A host can support up to 64 LAGs.
    • Note: the number of LAGs that you can actually use depends on the capabilities of the underlying physical environment and the topology of the virtual network. For example, if the physical switch supports up to four ports in an LACP port channel, you can connect up to four physical NICs per host to a LAG.
  • LACP is currently unsupported with SR-IOV.

LACP Compatibility with vDS

Basic LACP (LACPv1) is only supported on vSphere versions 6.5 or below. Upgrading ESXi to 7.0 may result in the physical switch disabling the LAG ports on ESXi hosts using Basic LACP.

For more information on Enhanced LACP in vSphere, see --> Converting to Enhanced LACP Support on a vSphere Distributed Switch- "Source vCenter Server has instance(s) of Distributed Virtual Switch at unsupported lacpApiVersion" 

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