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Stackable Switches: Why and Why Not

Posted on Nov 20, 2023 by
1.5k

In a rapidly evolving networking landscape, businesses require efficient and streamlined management solutions to stay ahead of the competition. Switch stacking has emerged as a powerful technique that not only simplifies network administration but also enhances overall efficiency. In this article, we will explore the concept of stackable switches and switch stacking, its benefits, and the potential limitations it may have.

What are Stackable Switches

A stackable switch is a device formed by connecting multiple switches logically as a single unit, which consists of three main elements: member switches, stack ports and stack cables. Member switches are individual units that make up the stack, including stack master, stack backup and stack member switches. Stacking ports are interfaces used to connect member switches, usually special interface modules or ports. Stack cables are dedicated cables used for physically connecting member switches, which transmit data and control information to enable member switches to work cooperatively.

What are Switch Stacking Technologies

There are two types of stacking technologies: backplane stacking and frontplane stacking. The former means the stack cables and ports are located on the back of stackable switches. The latter means the stack cables and ports are located on the front. For example, the S3900-48T4S switch has stacking ports on the front of a switch (dual 10G SFP+ ports).

A stacking switch can create various stacking topologies like daisy chain, full mesh and ring. Different topologies suit different scenarios and requirements. For example, compared with daisy chain, a ring topology provides redundancy and resiliency, as when one switch fails, data can be transmitted through the alternative path.

stacking topology

Stackable Switches: Why and Why Not

Whether you choose to switch stacking or not, considerations are crucial. Stackable switches offer versatility, but they may also have some limitations. Understanding specific needs and evaluating trade-offs is key to making an informed choice.

Why Use Switch Stacking?

Switch stacking resolves issues of low link utilization and high maintenance costs caused by redundancy in traditional campus networks. Its advantages include:

1. Simplify Management

By stacking switches, multiple switches can be managed and configured in a unified manner, improving management efficiency. The network administrator only needs to operate on the stack master switch to manage and configure the entire stacking system without configuring each member switch separately. In addition, a unified management interface also facilitates monitoring and troubleshooting.

2. Improve Reliability and Stability

Switch stacking enables redundancy backup to improve network reliability and stability. When the stack master fails, the backup switch can take over as the new master. This redundant design can greatly reduce the risk of network interruption and improve the overall system reliability. In addition, switch stacking can realize cross-device link aggregation by bundling multiple physical links into a logical link, which has provided higher bandwidth and redundancy, further enhancing network stability.

3. Increase Bandwidth

Through switch stacking, port aggregation across switches can be realized to bundle multiple physical ports into a logical port, increasing the network bandwidth capacity. For example, the S5860-20SQ switch has a maximum stacking bandwidth of 200G. When traffic load increases, load balancing can be achieved to distribute traffic to multiple physical links, improving bandwidth utilization. Therefore, switch stacking is very suitable for application scenarios requiring high-bandwidth transmission, such as data centers and video media streaming.

Why Shouldn't You Use Switch Stacking?

While switch stacking offers many benefits, it may not always be the optimal solution for every network environment. There are other potential disadvantages when using stacked switches:

1. Restricted Selection

Multiple switches used in switch stacking must be from the same vendor and series. If a vendor's product does not meet the requirements of a specific network environment, switches of other brands or models can not be used in stacking. This limits the flexibility and scalability of network architecture and may lead to the inability to achieve the optimal solution in some cases.

2. Resilience

A stacking switch runs in a single management or control plane mode. On the one hand, it can simplify management. On the other hand, it may reduce the overall resilience of the network. When the stack master encounters some specific failures, switch troubleshooting takes time, and other member switches in the stack may not work properly, resulting in slower network recovery speed.

3. Manageability

Expanding an existing switch stacking may cause lengthy service disruptions. A series of steps such as firmware upgrade, reconfiguration and testing are required for stack expansion, which may require suspending network services. In addition, removing a switch from the stack may involve a complicated process. FS has open network switches that support stacking and installed PicOS software, which can be managed automatically through AmpCon, eliminating corporate worries.

Conclusion

Stacking switches provide important solutions for networks that require high performance and reliability, such as large enterprises and data centers. Understanding the mechanism, advantages and disadvantages of stackable network switches can help you better apply and manage network infrastructure to meet the ever-growing network demands. If you want to have a deeper understanding of switch stacking, you can read the article Switch Stacking Explained: Basis, Configuration & FAQs.

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