# Xnor *xnor* is the Computer Systems Lab's core fiber optic router and switch. Although for all intents and purposes xnor behaves as a single switch, it is actually comprised of two [Cisco Catalyst 4500-X WS-C4500X-F-16SFP+](http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-4500-x-series-switches/data_sheet_c78-696791.html) switches, linked together using Cisco Virtual Switching System for redundancy. Each switch has 16 SFP+ ports, expandable up to 24. ## Uplinks xnor has one 10Gbps fiber optic uplink to TJ's core router for IPv4 traffic, and one 10Gbps fiber optic uplink directly to TJ's border router for IPv6 traffic. These are unfortunately not redundant for now, as there are limited ports available on the TJ core side. Thus, one of xnor's physical switches has the IPv4 uplink, and the other one has the IPv6 physical uplink. ## General Setup xnor serves as the CSL's aggregation switch and router. All top-of-rack switches are connected to xnor using two redundant 10Gbps fiber connections (one to each physical switch). Any traffic which needs to be routed across VLANs or needs to be routed to TJ's border network is routed by xnor. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://documentation.tjhsst.edu/machines/switches/xnor.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.