Zayo Group Delivers Fiber-Based Services To All CoreSite Data Centers

    Zayo Group Delivers Fiber-Based Services To All CoreSite Data Centers

CoreSite's data center platform and Zayo's extensive network combine to give
customers a secure data hosting and interconnection solution

PR Newswire

DENVER and LOUISVILLE, Colo., Dec. 17, 2012

DENVER and LOUISVILLE, Colo., Dec. 17, 2012 /PRNewswire/ --CoreSite Realty
Corporation (NYSE: COR), a national provider of powerful, network-rich data
centers, today announced that Zayo Grouphas extended its fiber-based services
to all CoreSite data centers in nine markets throughout North America. Zayo
Group is a global provider of Bandwidth Infrastructure services, including
Dark Fiber, and lit and IP services. Its 67,000-route mile network connects
sites in 231 markets on dense metro and intercity fiber assets.

Zayo's full suite of lit services is now available at each CoreSite location,
including wavelengths, Ethernet, and IP services. Additionally, Dark Fiber,
with diverse routes and facility entrances, is available at each CoreSite
location except Miami. Zayo brings an average of over 600 fibers into each
facility.

Companies can now integrate the network-centric computing platform of CoreSite
with Bandwidth Infrastructure services from Zayo. CoreSite's 2,000,000+ sq.
ft. of on-demand data center space and connectivity on Zayo's 67,000-route
mile fiber network are both available through a coordinated team.

"By bringing together best-of-breed providers, we can provide our customers
with a scalable, resilient solution. Customers can now colocate their
network-centric applications at all of CoreSite's world-class facilities and
have direct access to Zayo's extensive network," states Brian Warren, Vice
President of Product Management at CoreSite.

"The Zayo and CoreSite partnership expands connectivity for current and future
customers from both companies," states John Real, SVP of Sales for Zayo.
"We're proud to offer fiber-based services to all CoreSite data centers."

For further information on CoreSite, visit www.CoreSite.com or call
303-405-1000. For additional information on Zayo Group, visit www.Zayo.com or
call 303-414-4152.

About CoreSite
CoreSite Realty Corporation (NYSE: COR) is a national provider of data center
products and interconnection services. More than 750 customers such as Global
1000 enterprises, communications providers, cloud and content companies,
financial firms, media and entertainment, healthcare, and government agencies
choose CoreSite for the confidence that comes with customer-focused data
center products, service and support systems, and scalability. CoreSite's
network centric computing platform is a business catalyst, featuring the Any2
Internet exchange and network ecosystems, which include access to 225+
carriers and service providers and a growing mesh of more than 15,000
interconnections. The company features a diverse colocation offering from
individual cabinets to custom cages and private suites, with 14 data center
locations in nine major U.S. markets. For more information, visit
www.CoreSite.com.

About Zayo Group
Based in Louisville, Colo., privately owned Zayo Group (www.zayo.com) is an
international provider of fiber-based Bandwidth Infrastructure services and
carrier-neutral colocation and interconnection services. Zayo serves wireline
and wireless carriers, data centers, Internet content and services companies,
high bandwidth enterprises, and federal, state and local government agencies.
Zayo provides these services over metro, metro, national, international and
fiber-to-the-tower networks. With its acquisitions of USCarrier, FiberGate,
AboveNet, and First Telecom Services, Zayo's network includes 67,000 route
miles, serving 45 states and Washington, D.C. Its network serves approximately
10,258 on-net buildings, including 507 data centers, 513 carrier PoPs, and
2,664 cell towers. Zayo's colocation assets include 141,000 billable square
feet of interconnect-focused colocation space.

Forward Looking Statements
This press release may contain forward-looking statements within the meaning
of the federal securities laws. Forward-looking statements relate to
expectations, beliefs, projections, future plans and strategies, anticipated
events or trends and similar expressions concerning matters that are not
historical facts. In some cases, you can identify forward-looking statements
by the use of forward-looking terminology such as "believes," "expects,"
"may," "will," "should," "seeks," "approximately," "intends," "plans," "pro
forma," "estimates" or "anticipates" or the negative of these words and
phrases or similar words or phrases that are predictions of or indicate future
events or trends and that do not relate solely to historical matters.
Forward-looking statements involve known and unknown risks, uncertainties,
assumptions and contingencies, many of which are beyond CoreSite's control,
that may cause actual results to differ significantly from those expressed in
any forward-looking statement. These risks include, without limitation: the
geographic concentration of CoreSite's data centers in certain markets and any
adverse developments in local economic conditions or the demand for data
center space in these markets; fluctuations in interest rates and increased
operating costs; difficulties in identifying properties to acquire and
completing acquisitions; significant industry competition; CoreSite's failure
to obtain necessary outside financing; CoreSite's failure to qualify or
maintain its status as a REIT; financial market fluctuations; changes in real
estate and zoning laws and increases in real property tax rates; and other
factors affecting the real estate industry generally. All forward-looking
statements reflect CoreSite's good faith beliefs, assumptions and
expectations, but they are not guarantees of future performance. Furthermore,
CoreSite disclaims any obligation to publicly update or revise any
forward-looking statement to reflect changes in underlying assumptions or
factors, of new information, data or methods, future events or other changes.
For a further discussion of these and other factors that could cause
CoreSite's future results to differ materially from any forward-looking
statements, see the section entitled "Risk Factors" in CoreSite's most recent
annual report on Form 10-K, and other risks described in documents
subsequently filed by CoreSite from time to time with the Securities and
Exchange Commission.

SOURCE CoreSite Realty Corporation

Website: http://www.coresite.com
Contact: Jeannie Zaemes, CoreSite, Marketing Senior Director +1-720-446-2006,
866-777-CORE, Jeannie.Zaemes@CoreSite.com; or Matt Brouker, Director of
Marketing, Zayo, +1-303-414-4152, 866-364-6033, Matthew.Brouker@Zayo.com