This article lists the differences in Link Aggregation Control Protocol (LACP) support between vSphere 5.1 and vSphere 5.5 Distributed Switches.

VMware vSphere ESXi 5.5
VMware vCenter Server 5.5.x

Feature	vSphere 4.x/5.0	vSphere 5.1	vSphere 5.5
LACP Support	No	Yes	Yes
Multiple LAGs per uplink port group	N/A	No	Yes
Multiple LACP load balancing algorithms	N/A	No	Yes

vSphere 5.5 Distributed Switches support multiple link aggregation groups (LAGs) per uplink port group, whereas vSphere 5.1 supports only a single LAG. This provides improved flexibility and eliminates the need to have multiple distributed switches to support more than one LAG.

Note: A maximum of 64 LAGs can be created per Distributed Switch in vSphere 5.5. However, the underlying physical network infrastructure may impose additional limitations that limit the number of LAGs.

vSphere 5.5 Distributed Switches support all load balancing algorithms associated with LACP,where as vSphere 5.1 supports only the IP Hash load balancing algorithm.

For information on enabling enhanced LACP features, see Converting to Enhanced LACP Support on a vSphere Distributed Switch in the vSphere Web Client (2051311).

Though vSphere 5.5 supports enhanced LACP capabilities, the Distributed Switch must be upgraded to a version 5.5 to take advantage of these features. This requires that all ESXi hosts connected to the distributed switch are also upgraded to ESXi 5.5, which removes the backward compatibility with older versions. Limitations of LACP in VMware vSphere 5.5
Converting to Enhanced LACP Support on a vSphere Distributed Switch in the vSphere Web Client
従来の VMware vSphere Client を使用してリンクアグリゲーショングループ (LAG) を作成すると失敗し、次のエラーが表示される：Basic support
vSphere 分散仮想スイッチの健全性チェックの機能で [VLAN および MTU] を有効にすると、次のメッセージが vmkernel.log に大量に出力される： VLANMTUCheck: NMVCPortVLANResultPoll:320: not find psReq for ps DvsPortset
vSphere Distributed Switch 5.5 と 5.1 の LACP サポートの違い