The LGS552P supports 802.1Q VLANs. Up to 1024 active 802.1Q VLANs can be configured, using numbers from 1-4096. I tested untagged and tagged VLANs between the LGS552P, a Cisco SG200-26 and a NETGEAR GS108T. The LGS552P successfully passed VLAN tags over trunks to and from both switches. Below is a screenshot showing multiple ports configured as access or trunk ports with different VLAN assignments.
The LGS552P data sheet lists support for port-based VLANs, yet port-based VLANs aren't mentioned anywhere in the manual. Further, there isn't a configuration option for enabling port-based VLANs. Moreover, port-based VLANs on an 802.1Q switch (see my how to here) require ports that can be untagged members of multiple VLANs, which doesn't appear to be supported by the LGS552P.
The LGS552P supports a single Voice VLAN, which can be automatically assigned to ports with recognized VoIP devices. If a VoIP device with a recognized OUI (Organizationally Unique Identifier = the first six characters of the MAC address) sends a frame on a Voice VLAN enabled port, that port will be enabled as a tagged member of the Voice VLAN. I added a couple VoIP devices and their OUI to the LGS552P and observed the switch correctly make their ports tagged members of the Voice VLAN.
In the screenshot below, you can see I've added Grandstream and Panasonic OUIs. In my previous VLAN screenshot, notice that ports 3 and 5 are tagged members of VLAN 4, which is the Voice VLAN I created. Ports 3 and 5 automatically became tagged members of VLAN 4 by enabling the LGS552P Telephony OUI Voice VLAN feature and detecting the OUIs of the Grandstream and Panasonic VoIP devices. Note there doesn't appear to be an LLDP (Link Layer Discover Protocol) option to automatically communicate the Voice VLAN ID to the VoIP device, so putting Voice traffic onto the Voice VLAN may also require manual configuration of the VoIP device.
A guest VLAN can also be defined where devices are placed in specific VLAN based on authentication permissions. I'll discuss authentication in the security section below.
Spanning Tree Protocol is enabled by default. Both STP and RSTP (Rapid Spanning Tree Protocol) are supported, with RSTP as the default. I gave the LGS552P my usual STP test, which is to plug both ends of an Ethernet cable into two ports of the switch on the same VLAN. With STP disabled, the switch would likely crash. With STP enabled, there should be little or no network interruption.
I connected my Ethernet cable to ports 13 and 14 with STP enabled. As shown below, port 14 has been placed into a Discarding state, meaning it is not passing traffic, successfully preventing a switching loop.
Rapid Spanning Tree
The LGS552P supports up to four Link Aggregation Groups (LAGs) with up to 8 ports per LAG. Automatic LAGs utilizing Link Aggregation Control Protocol (LACP) and manual LAGs are supported.
I had no problem setting up a LAG between the LGS552P and a Cisco SG200-26. The key to setting up a LAG is to first make sure all the ports in the LAG are members of the same VLAN and have the same port type (access or trunk). Then add the ports to the LAG and assign additional VLANs to the LAG instead of the ports. In the screenshot below, you can see the ports GE25 and GE26 are members of an active LAG utilizing LACP to establish the connection.