Top-of-rack Switch Advantages and Selecting Considerations

Updated on Jun 1, 2022 by

25G Switch

With the development of data centers, two network architectures have been derived: TOR and EOR. The applications of these two network architectures are different. End-of-rack switches are more suitable for traditional data centers that do not require high scalability, while top-of-rack switches are more suitable for access switches or aggregation switches in modern data centers with high scalability. This article will focus on top-of-rack switches.

What Do You Know About the Top-of-rack Switches?

Top-of-rack switch, called a TOR switch, is placed on the top of a rack cabinet. In fact, the core of TOR is to deploy the switch in the server cabinet, whether on the top of the cabinet, in the middle of the cabinet, or on the bottom of the cabinet. Generally speaking, deploying the switch on the top of the cabinet is the most conducive to routing, so the top-of-rack architecture is most widely used. It can be used as an access switch or an aggregation switch to connect user data or aggregate data from the access layer.

Top-of-Rack Switch Features

What are the essential performance characteristics of a top-of-rack switch in a high-density data center network? Here is the answer for you.

  • Overall performance. TOR switches, undertaken by box switches of 1U to 2U in height, have powerful CPU performance and switching chips, which can provide reliable and stable L2/L3 network switching services. Further, the operating system also offers some basic features, such as L2/L3/ACL/QoS/security, as well as open RPC API.

  • Cache and capacity. The top-of-rack switches adopt a distributed cache architecture, which can accurately identify and control data to achieve zero packet loss. Of course, they also have high capacity forwarding features and supports 32/48/64/128 ports high-density ethernet boards.

  • Ports. Top-of-rack switches support 25G/40G/50G/100G port types, as well as managed ports, featuring high backplane bandwidth. Also, TOR switches can use both ethernet and optical ports.

  • Virtualization technologies. The applications of virtualization technologies are PFC, EVPN-VXLAN, MLAG, and ECN. EVPN is one of the extensions of BGP that allows the network to carry network layer reachability information (NLRI) and provides multipath forwarding and redundancy through an all-active mode, and convergence with VXLAN can greatly improve network performance.

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Advantages of Top-of-Rack Switching

High-performance TOR data center switch can handle L2 and L3 traffic forwarding, data center bridging, and fibre channel over ethernet (FCoE) for the entire server rack. Here are the other advantages of TOR switches bring:

Less Clutter

Top-of-rack architecture eliminates the clutter and chaos often found in data rooms. Servers within each cabinet are directly connected to the internal switch, reducing the number of cables running to the aggregate switch. This not only saves costs by requiring fewer cables, but also eliminates the need for extensive copper cabling throughout the data center.

Flexibility in Placement

Despite the term "top-of-rack," the switch can be installed in the middle of the cabinet, offering flexibility in placement. This allows for standardized cable lengths and creates a more efficient environment with fewer ventilation obstructions. Keeping equipment cool becomes easier with reduced cable mess.

Easy to Rearrange

Top-of-rack switching is highly modular, simplifying deployment and allowing for quick rearrangements within the data center. Cabinets can be moved with minimal disconnections and inconvenience, thanks to the minimized external cabling. This avoids time-consuming overhauls when adapting to changes in room layout.

Efficient Troubleshooting

The modular nature of top-of-rack switching simplifies troubleshooting. Issues are typically isolated to individual cabinets instead of affecting an entire row. This targeted approach makes problem diagnosis and resolution much easier compared to end-of-row systems.

More Futureproof

Upgrading a top-of-rack system is a streamlined process with minimal impact beyond the specific cabinet being worked on. This makes top-of-rack architecture ideal for those who prioritize a more future-proof data center in the ever-changing world of IT.

Top-of-rack Switch Selection Considerations

According to the performance characteristics and advantages of top-of-rack switches, some factors must be fully considered to successfully deploy top-of-rack switches in a data center.

System Functions

TOR switches need to support rich virtualization technologies, such as stacking or MLAG, which can effectively improve the network deployment efficiency and reduce labor costs. Some system functions also need to be considered, which will facilitate the deployment and management of equipment in the future. You can choose the TOR switches with ZTP (Zero Touch Provisioning) function to automatically configure. After running ZTP, the switch can obtain the version file from the U disk or file server and load it automatically to realize the rapid configuration of the equipment.

Deployment Consideration

For the TOR architecture, each cabinet is an independent management entity. When servers or switches need to be upgraded, you can upgrade them one by one into rack units. In addition, the upgrade process does not affect the traffic forwarding of other cabinets. Typically, TOR switch uplink will prefer optical fibers, as optical fibers have advantages over copper in the long run. Optical fibers can carry higher bandwidths, and when higher-speed links need to be replaced, the selection of optical fibers is also more flexible. Therefore, when choosing a TOR switch, you need to consider the flexibility of the number and rate of uplink and downlink ports on the switch, and whether they can be split out to complete other types of service transmission.

It is worth noting that for the port utilization problem. If the switch ports in a server cabinet are not fully utilized, you can try to cross-wiring with the adjacent server cabinets, which can reduce port waste to a certain extent.

Equipment Reliability

In the TOR architecture, software faults or incompatibility of the operating system in the equipment can cause some serious problems and may also reduce the lifespan of the equipment. Although they can not affect the equipment in other cabinets, they will have a certain impact on the connected server equipment and aggregation layer switches, causing problems such as data loss. To avoid this problem, you need to choose a switch that matches your settings and that the software operating system you fully trust.

Data Center TOR Switches Recommendation

Choosing top-of-rack switches with advanced virtualization technology and abundant port counts as access-layer switches and aggregation-layer switches can bring you better network stability and economic benefits. Like FS top-of-rack switches, the number of ports is at least 32, and there are various types to meet your various network needs. FS top-of-rack switches are equipped with high-end virtualization technology, especially EVPN-VXLAN required by existing equipment. As mentioned earlier, EVPN provides multi-path forwarding and redundancy through an all-active model. Top-of-rack switches can connect to multiple aggregation switches and use all links to forward traffic, greatly improving network performance.

In addition, FS top-of-rack switches provide manageability and security features as high-performance data center switches, which can effectively resist and control virus flooding and hacker attacks to strengthen network security. These switches also offer various network traffic reports to help you optimize the network structure and adjust the deployment of internal resources.

Products N5860-48SC N5850-48S6Q N8560-32C N8560-64C NC8200-4TD
Ports 48x 10G SFP+| 8x 100G QSFP28 48x 10G SFP+, 6x 40G QSFP+ 32x 100G QSFP28 64x 100G QSFP28 128x 10G/25G, 64x 40G, or 32x 100G
Number of VLANs 4K 4K 4K 4K 4K
Switching Capacity 2.56 Tbps 1.44 Tbps full duplex 6.4 Tbps 12.8 Tbps 6.4 Tbps
Forwarding Rate 1.90 Bpps 1 Bpps 4.76 Bpps 9.52 Bpps 4.76 Bpps
Flash Memory 8GB 16MB 240GB 8GB 8GB
Packet Buffer 32MB 16MB integrated packet buffer 32MB 42MB 32MB
IPv4/IPv6 Routes 128,000/64,000 / 128,000/64,000 128,000/64,000 128,000/64,000
Application Access layer Access layer Aggregation layer Aggregation layer Access layer, Aggregation layer

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