4.3: System Scope

Managing Technology Projects · LibreTexts

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    From LibreTexts, under CC BY 4.0, as the source states it; its equations are written in TeX, which the PDF shows typeset. This page at LibreTexts.

    Now that we have defined what a network switch is and have described the types of network switches, we are going to look at the scope that this case study is going to address.

    For simplicity, we are not going to address the development of a large modular switch. As mentioned in the prior section, its scope is complex, requiring the development of:

    • Multiple line card types
    • A management or supervisor board that typically would be used in a redundant configuration (two management boards)
    • A backplane
    • A power backplane or other power distribution system.
    • A large mechanical enclosure to house the management modules, line cards, backplane, power distribution system, redundant hot-swappable fan trays and power supply units. Typically a complex finite element cooling analysis needs to be performed to ensure adequate air flow, especially to hot spots (components that rise to a high temperature when operating). This may require designing special baffles to intelligently direct airflow.

    Instead, we are addressing the smaller pizza-box sized 1-2 RU standalone switches with fixed I/O port configurations.

    Since this CIS 79 Managing Technology Projects course is part of the De Anza College project management certificate and degree curriculum, we are going to look at this development effort through the lens of the project manager assigned to the project rather than through the lens of a system design team chartered with the engineering effort to develop the system.

    Network switches can be complex systems, comprised of hardware and software components. A project manager's scope might be to handle the entire system, just the hardware, or just the software. There is also a middle ground in which the project manager handles the hardware as well as a piece of the platform software, the software that provides support for the underlying hardware, especially the networking Application Specific Integrated Circuits (ASICs). The hardware project manager would be working closely with the software project manager, often called a software release project manager.

    Since a lot of the De Anza curriculum is software centric, for balance, we will concentrate on addressing the hardware elements. This will provide better preparation to be "industry-ready."

    Design choices

    In De Anza College's CIS 43 Systems Design course (which one of the authors teaches), there are design alternatives and various "make versus buy" decisions that need to be addressed. How one approaches these decisions will be guided by the requirements filed by the product manager regarding the required system capabilities.

    Network Application Specific Integrated Circuits (ASICs) do the heavy-lifting of the needed switching functionality such as packet switching, forwarding, routing, quality of Service (QoS) and some security protocols. Some networking companies maintain their own ASICs development teams to retain their edge in the competitive marketplace. There are companies that develop network ASICs that they sell to network switch companies for incorporation into their product offerings. These third party or merchant silicon ASICs come with an SDK (Software Development Kit) that provides software support for the ASICs. The SDK needs to be incorporated into the network switch vendor's network operating system. The SDK can come with a Command Line Interface (CLI) that provides an almost ready to use system, albeit usually at the low end.

    A classic "make versus buy" decision is who does the major work on the hardware development effort. Should it be done using the network switch company's hardware design team, or could it be done by an external ODM (Original Design Manufacturing or Manufacturer)? An ODM can not only perform the design work, but also do the manufacturing. There may be a catalog from the ODM of already developed products or very similar ones from which to choose.

    Another design choice (albeit a software one) is what CLI (Command Line Interface) to offer the user for interacting with the switch. One can use a proprietary interface (your own commands and syntax) or consider offering a CISCO-compatible CLI that many networking professionals are used to using.

    There will be more on this in subsequent sections.

    4.3: System Scope is shared under a CC BY 4.0 license and was authored, remixed, and/or curated by LibreTexts.