Difference between VSS vs Local Stacking Vs Horizontal Stacking

Today I am going to compare VSS with Local stacking, Horizontal Stacking and Distributed Stacking. Before we compare these in a table, let's talk a little bit on all these one by one

VSS-Virtual switching systems
The concept of Cisco VSS which is called as Virtual switching systems where a pair of Catalyst 6500/6800/4500 series switches into a single network element. The VSS manages the redundant links which externally act as a single port channel.The VSS simplifies network configuration and operation by reducing the number of Layer 3 routing neighbours and by providing a loop-free Layer 2 topology.

An access switch connects to both chassis of the VSS using one logical port channel. The VSS manages redundancy and load balancing on the port channel. This capability enables a loop-free Layer 2 network topology. The VSS also simplifies the Layer 3 network topology because the VSS reduces the number of routing peers in the network.

Stack Switching:
Stack Switching is the concept of stacking the various switching via stack cables so that they can act like a single switch with various ports. Lets us suppose we have a requirement of 200 users at access layer, what to do which switch you will recommend here, Let me talk about Cisco 3850 with 48 port switch now with Cisco 3850- 48 port you can't fill your 200 users requirement, so you required 5 quantity of Cisco 3850 switches in a stack and in this way you have 240 user ports which can fill your requirement.

Fig 1.1- Switching Stacks

You can stack upto 9 switches if i am talking about Cisco 3750 or Cisco 3850 Switches in the enterprise network.One of the Cisco EtherSwitch service modules or Catalyst 3750 switches controls the operation of the stack and is called the stack master. The master LED in the front panel of the 3750 switch turns green when the switch becomes master in the stack. 

The stack master and the other Cisco EtherSwitch service modules or Catalyst 3750 switches in the stack are stack members. The stack members use the Cisco StackWise technology to behave and work together as a unified system. Layers 2 and 3 protocols present the entire switch stack as a single entity to the network.

Fig 1.2- Star and Ring Stack Scenarios
You can check out the basics about VSS and the difference between VSS and Stacking at Access on below link 

Horizontal Stacking
The Catalyst 3560CX series switches associate 10G SFP+ uplink ports and MGig ports can be part of horizontal stacking. We can use SFP+ with the optical cables and copper cables on the MGig ports to attach boxes placed at different location to form a stack, where the compact boxes are placed in different floors or buildings. We can form half-ring or full-ring based on need, and remaining uplink ports will continue to work as network ports.

When we change a network port to stack port, it will endure to work as network port without any influence to current running configuration till next reload of switch. All current configurations of that specific network port will be lost after reload of switch once port comes up as Stack port.

When we convert a stack port back to network port it will continue to work as stack port until next reload of switch. After reload port comes up as network port with default configuration.

Below table shows the difference between VSS, Local Stacking, Horizontal and Distributed Stacking

Fig 1.3- Comparison between VSS and other stacking