4.5: Software System Design

Network Operating system

The network operating system provides support for the switch device's underlying hardware, provides support for a myriad of network protocols, helps manage network traffic, provides a user interface, provides support for network operations management by network administrators through a network management system (NMS) using SNMP for example, provides monitoring and alerts, and tracks network performance.

Examples of network operating systems are:

• Cisco IOS,
• Juniper Junos, and
• Arista EOS.

Platform Software

Platform software manages the switch's hardware. This includes the networking ASICs, I/O port interfaces, power supplies, and fan trays.

Software can monitor the speed of fans in the fan trays and fans in power supplies to detect a degradation of speed, which might be indicative of a need to replace the unit before it fails.

Since some vendors support products using their own custom networking ASICs as well as merchant silicon networking ASICs, the networking operating system might be structured to provide a hardware abstraction layer (HAL) to more easily support both types of platforms.

Broadcom SDK(from Google search summary, rephrase)

As discussed earlier, merchant silicon is available, providing the network ASICs that do the heavy lifting of providing switching functionality.

One of the critical deliverables in a Software Development Kit (SDK) or Switch Development Kit (SDK) provided by the ASIC supplier are the device drivers for the networking ASICs. The SDK needs to be integrated into the network operating system software that runs on the switch.

The switch vendor's network operating system likely has a Hardware Abstraction Layer (HAL) as mentioned previously. It will use Application Programming Interfaces (APIs) to communicate with the ASIC supplier's SDK. The SDK in turn interfaces with the ASICs to initialize them, configure them, and monitor them.[3]

Broadcom is one of the leading suppliers of merchant silicon ASICs. The Broadcom Unified SDK (or OpenBCM SDK) provides APIs, drivers, and tools for programming the various Broadcom network switch silicon platforms.

The SDK provides low-level access to Broadcom ASIC hardware, enabling the network operating system to configure packet forwarding, VLANs, QoS, multicast, and other advanced networking features.

It supports various ASIC families as follows:

• XGS devices (e.g., Trident TD2/TD3/TD4, Tomahawk TH/TH2/TH3) and
• DNX devices (e.g., Ramon, Qumran Q2A/Q2U, Jericho JR2/J2C).

Key SDK pieces include:

• Application Programming Interfaces (APIs) for direct hardware programming.
• Abstraction of low level hardware constructs (registers) to simplify programming.
• Device drivers for various Broadcom ASICs. The device drivers work with a layer called the SOC layer (presumably for System on a Chip) to communicate with the ASICs.
• Sample applications demonstrating feature usage.
• A build system for compiling and linking SDK modules into the switch platform.

Support for Network Protocols

A network switch developer publishes a data sheet when the system product is launched into the market. The data sheet usually has a section entitled something like "Standards and protocols" that provides a long list of the networking standards and protocols that the network switch supports. This includes (by general categories):

• ANSI standards (for example, ANSI/TIA‑1057 LLDP Media Endpoint Discovery (LLDP‑MED)
• IEEE networking standards, for example:
  • IEEE 802.3ab 1000 BASE‑T
  • IEEE 802.3ae 10‑Gigabit Ethernet
  • IEEE 802.3ae 10‑Gigabit Ethernet
  • IEEE 802.1Q VLANs
• RFCs. The The Internet Engineering Task Force (IETF) publishes its technical documentation as RFCs (Requests for Comments.) They describe the Internet's technical foundations, such as addressing, routing, and transport technologies. For example:
  • RFC 826 ARP

Features

Some features that have been incorporated into a specific software release are documented in the "Release Notes" for that release.

Command Line Interface (CLI)

The network operating system provides a command line interface as a means for issuing commands to the switch to configure and manage it.

Network Management

A Network Management System (NMS) is software that helps with monitoring, controlling, and automating the operation of a network switch. It also provides a means for monitoring the health of the switch and in maintaining it.

References

1. IETF | Introduction. Accessed February 19, 2026.
2. Network operating system - Wikipedia. Accessed February 19, 2026. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
3. Broadcom switch SDK software enables rapid development and deployment. Accessed February 23, 2026.