25 Gb For Campus Networks – Just Upgrade It!

Written by: Priya Maratukulam, Product Manager, Cisco Transceiver Modules Group

Enterprise campus networks are straining to support increasingly bandwidth-hungry endpoints.  Networks support more devices that deliver richer content like HD (High Definition) video and advanced technology such as Wi-Fi 6.  Enterprises can future-proof their networks with greater bandwidth while minimizing invasive changes by migrating to 25Gb links between aggregation and access switches.  25Gb not only gives 2.5 times the bandwidth of a 10Gb lane, it also provides a seamless upgrade path to 100Gb. Upgrading to 25Gb also allows for reuse of existing cabling, reducing capex. Although there are many benefits of 25Gb, this blog post will focus on the economics of 25Gb vs. 10Gb.

The new Catalyst 9500 Series Switches are designed for enterprise-class core and aggregation applications.  The Catalyst 9300 Series stackable switches, with 4-port 25Gb network uplink modules, can provide 25Gb connectivity from the access layer to the aggregation layer.  With Catalyst 9500/9300 and Cisco optics, IT staff can deploy a network fabric with 25Gb bandwidth without ripping and replacing cables. Below is an example of an enterprise network architecture with Catalyst 9300 in the access layer and Catalyst 9500 in the aggregation layer.

Example of an enterprise network architecture using 25G links between aggregation and access layers.

Additionally, the cost difference between deploying 10Gb vs. 25Gb is minimal.  Catalyst 9500 and 9300 25Gb ports can also operate at 10Gb. Therefore, customers have the option of using either 10Gb or 25Gb optics in the 25Gb ports. However, the additional cost of 25Gb optics adds only 1% to the total BOM cost. For comparison, below are two BOMs (Bills Of Material) for an actual campus deployment at an enterprise that employs 5,000 people.

Total cost comparison between a 10Gb and 25Gb based system, using a configuration for a 5,000 person enterprise.

The benefits of the 25Gb bandwidth outweigh any budgetary concerns. For IT managers the choice is clear: 25Gb optics provide a 150% increase in bandwidth for only 1% increase in cost.