Changes
→Network Topology: Significantly rewrite for current network topology
== Network Topology ==
In Blacksburg, CNS has redundant fiber uplinks from the [[Andrews Information Systems Building]] to Ashburn, Virginia and Atlanta, Georgia. The [[Mid-Atlantic Broadband Communities Corporation]] provides the dual OC-192 (10 Gigabit) connections connection to Ashburn and the additional OC-192 connection to Atlanta. The connection to Ashburn terminates at the [[Andrews Information Services Building]] and the connection to Atlanta terminates at [[Hillcrest Hall]]. In summer 2015, the OC-192 connection to Ashburn will be upgraded to OC-768 (possibly two?100 Gigabit) to Atlanta.<ref>[https://www.vtnews.vt.edu/articles/2015/04/042115-it-gigabits.html]</ref>
From the Andrews Information Systems Building, there are redundant fiber connections to the main campus at both [[Burruss Hall]] and [[Cassell Colliseum]]. [[Owens Hall]], [[Hillcrest Hall]], and [[Shanks Hall]] have intermediate routers for some buildings. Nearly all ethernet portals on campus are capable of 100 Mbps or Gigabit speeds, due to fiber interconnects between buildings; however, intrabuilding wiring varies in age and may not support high speeds. The vast majority of campus IPv4s come from two directly-allocated blocks (128.173.0.0/16 and 198.82.0.0/16).
=== IPv6 ===
CNS is a leader in the transition to IPv6, as their [[w:Autonomous System|ASN]] consistently ranks in the top 5 in terms of percentage of IPv6 traffic, according to [http://www.worldipv6launch.org/measurements/ World IPv6 Launch Measurements]. A dual-stack topology exists for the entirety of campus, but not all systems connected to the network are IPv6-enabled. One system that notably lacks connectivity is the main vt.edu website, which is due to a lack of support from the load balancers currently in use. For legacy reasons, Virginia Tech continues to use its /48 sub-allocation from the [[w:University of Maryland|University of Maryland]], instead of its assigned IPv6 block (2607:b400::/32). It is unknown when the new address space will begin to be used.
=== Unified Communications ===
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.