'''Communications Network Services (CNS)''' is a division of the Office of the Vice President for Information Technology, which provides ISP services including telephone and Internet to the university. Unlike most departments, CNS operates as an auxillary service, and therefore recieves funding through cost-recovery rather than university budgets. Individual departments and students must pay a ''per-port'' charge for each IP or phone device attached to the network.

In Blacksburg, CNS has redundant fiber uplinks from the [[Andrews Information Systems Building]] to an upstream router in Equinix's [[Ashburn, Virginia]] datacenter. At Equinix, CNS has about 4 Gbps aggregate bandwidth for commodity Internet from Cogent, as well as, through the [[Mid Atlantic Terascale Partnership]], connections to [[Network Virginia]], [[National LambdaRail]], and [[Internet2]].

In December 2011, CNS announced that a contract had been awarded to IBM and Avaya for ''Unified Communications'', a project to both replace the aging ROLM phone system with SIP phones and upgrade the network infrastructure in each building. This has also somewhat reduced monthly rates of common telephone and ethernet services for departments. While most buildings will be undergoing upgrades through 2014, it is unknown whether or not each will have full gigabit speeds at actual user ports. It is also unknown whether users will be able to use SIP softphones in conjunction with this.

Contrary to popular belief, CNS does not actively monitor users for torrenting activity; however, they are obligated to forward DMCA notifications to the relevant parties. Residential users that engage in peer-to-peer filesharing are often throttled (according to policy) if their daily upload average exceeds 4.9 GB. Campus-wide intrusion detection systems are deployed through cooperation with the [[IT Security Lab]].

NAT routers are officially banned, largely due to dorm residents bringing their own NAT router, plugging it in backwards, and sending DHCP leases to their entire building. While the ban is generally unenforced unless a problem arises, users are encouraged to purchase additional connections through CNS instead.

In addition to the network policies stated above, the following controversial activities have arisen:

* CNS has begun deploying [[w:Network Address Translation | NAT]] to dorm buildings, starting with the [[Graduate Life Center]]<ref>[http://ipv6.cns.vt.edu/ IPv6 at Virginia Tech]</ref>, as it has done in the past with wireless access points.

* Like most administrative university offices, CNS is often regarded as having much bureaucracy. For example, the processes for obtaining SSL certificates or a DNS entry directly under "vt.edu" are especially tedious.

* CNS services such as VPN and VT-Wireless (the secure wireless network) require use of MS-CHAPv2, which is proven to be very insecure.

[[Category:Blacksburg ISPs]]