Normally, several network switches are combinied together to meet network needs (port number, certain functions, etc.) when one switch can't. There are various approaches to connect multiple switches, among which switch stacking vs trunking vs uplink are the most prevailing methods. This post aims to elaborate the three switch-connecting methods and indicate which one to choose in practice.
Switch stacking is to combine multiple switches to make them work together and operate as one logical unit. The port density of a stack unit is the sum of the combined ports and the switching capacity will be much augmented. Know more information about switch stacking here: Switch Stacking Explained: Basis, Configuration & FAQs.
Figure 1: Switch Stacking with 4 FS S3800-24T4S 24 Port Switches
Switch trunking refers to a method that a network system provides network access to many switches by sharing a set of links instead of providing them individually. It is similar to the structure of a tree with one trunk and many branches. Based on layer 2 technology, trunking is often used to form an internetwork including LANs, VLANs, and WANs. It enables packets encapsulated for multiple VLANs to cross exactly the same port and then retains the traffic separation among them. Just as the picture below shows (Figure 1), each switch is configured with 2 VLANs (10 and 20). There is a single communications channel (VLAN trunk link) between the two switches, over which traffic for both VLANs can pass. In the VLAN trunk link, each switch has a port designated as a trunk port to allow data flow between these VLANs.
Figure 2: VLAN Trunking with 2 FS S3800-48T4S 48 Port Switches
Switch uplink is a subjective concept which means that the cascading of ports between two switches is facilitated via the so-called “uplink port”. Uplink ports often have higher data rates than normal interfaces and are designed for inner-switch connection with a standard straight-through cable or direct attach cable. As is illustrated below (Figure 2), to build an uplink between two SFP switches, you can simply plug the uplink port of one switch into the uplink port of the other switch using a 10G SFP+, which can help expand the network scale.
Figure 3: Switch Uplink with 2 FS S5800-48F4S SFP Switches
The table below shows the differences among switch stacking vs trunking vs uplink.
||Switch Stacking||Switch Trunking||Switch Uplink|
|Port Density||The port density of a stack unit is the sum of the combined ports||The ports of the two switches can't be superposed||The ports of the two switches can't be superposed|
|Switch Interoperability||Switch stacking requires the same model of Ethernet switches from the same vendors||Most network switches in market support trunking regardless of models and vendors, which ensures the connection between different VLANs||Switch uplink offers a perfect fit for connecting switches from different product family|
|Number of Switches||Switch stacking is stricter about the number of switches to be stacked(different vendors may have respective standards)||Switch trunking is flexible in the number of switches. You can just add as many switches for trunking based on your needs||Switch uplink is flexible in the number of switches. You can just add as many switches for uplink based on your needs|
|Port Connection||Through dedicated stacking ports (when a switch has) or through uplink ports||Any port can be designated as a trunk port to realize switch trunking||Generally, only uplink ports can be used to achieve switch uplink|
|Performance||Each stack member shares a single IP address and acts as a whole unit||There is a single communication channel (VLAN trunk link) between the two switches directly connected with each other , over which traffic for both VLANs can pass||Each switch that is connected stands alone and works independently|
|Application||When you need to expand your bandwidth as much as possible. Moreover, switch stacking can be used to provide link redundancy to prevent failure in the link. Even if one link breaks in the stack unit, the other switches can continue to work.||You can handle multiple signals simultaneously and extend your configured VLANs across the entire network, making it extremely appropriate for public places such as apartments or dormitories that cover many sub-networks||Uplink port is usually utilized to connect to aggregation switch or core switch|
The three methods have their respective pros and cons. So switch stacking vs trunking vs uplink, which one to choose depends on your real needs. In general, switch stacking offers more bandwidth while simplifies network management, proven as a more cost-effective alternative to chassis-based higher-end switches. Switch trunking is a great option for inter-network including LANs, VLANs, and WANs, which requires network integrity as well as retains the traffic separation. Switch uplink is preferred when you want to upgrade your network. For example, in the network scenario of 10G-40G, you can connect the QSFP+ uplink on a 10GBase-T switch to a 40G switch in common cases.
Related Article: MLAG vs. Stacking: What Is Your Option?