When designing a data center network, your company wants to minimize the number of network cables to install. What type of physical cabling layout would be the best choice?

The Top of Rack (ToR) design places an access switch directly within each server rack. Servers in the rack connect to this switch using short, easy-to-manage patch cables. This architecture minimizes the number and length of structured cables that must be run across the data center to a central aggregation point. By localizing the server-to-switch connections, ToR significantly reduces cable clutter, simplifies installation and maintenance, and lowers the overall cost and complexity associated with cabling infrastructure compared to alternatives like End of Row (EoR).

B. End of Row (EoR) design: This design requires running a long, individual cable from every server port to a large aggregation switch at the end of the row, drastically increasing cable quantity and complexity.
C. Star network design using coaxial cables: A star network is a logical topology, not a specific physical data center layout like ToR/EoR. Furthermore, coaxial cable is an obsolete medium for modern high-speed data centers.
D. It does not matter as the number of switches is not influenced by the physical cabling layout: The physical layout is a primary determinant of the cabling infrastructure. ToR and EoR designs have fundamentally different implications for the quantity, length, and management of cables.

1. Schneider Electric. (2013). White Paper 179: Choosing Between Top-of-Rack and End-of-Row Data Center Architectures (Revision 1). Page 4, "Cabling". The paper states, "The ToR approach greatly simplifies cabling by placing the access switch in the rack with the servers. This allows for the use of shorter, less expensive cables... In contrast, the EoR approach results in large bundles of copper cables that must be managed."

2. Cisco. (2014). Data Center Top-of-Rack Architecture Design White Paper. Page 4, "Cabling Simplicity". This document explains, "With the ToR model, most of the cabling is within the rack... This approach greatly simplifies the cabling infrastructure because the length of the cables is short and contained within the rack."

3. Al-Fares, M., Loukissas, A., & Vahdat, A. (2008). A Scalable, Commodity Data Center Network Architecture. In Proceedings of the ACM SIGCOMM 2008 conference on Data communication (SIGCOMM '08). Association for Computing Machinery, New York, NY, USA, 63–74. https://doi.org/10.1145/1402958.1402967. This foundational academic paper on data center architecture discusses the use of ToR switches (p. 65, Section 3) as a fundamental building block to manage cabling and scale connectivity efficiently.