The New Network
Explore Juniper’s vision for network innovation and how the company and industry are shaping the future with the new network
Showing results for 
Search instead for 
Do you mean 

When is a Fabric not a Fabric?

by Juniper Employee on ‎04-05-2011 05:14 PM


On March 30, Cisco announced an update to their data center “vision.”  We are pleased to see that they have endorsed our view of the problem—that the legacy multi-tiered data center network architecture must change to enable a truly virtualized data center.  This evolution will begin with the architecture, where hierarchical tree structures will give way to flat fabrics.  We at Juniper have been promoting this vision for the last two years and Cisco has now joined the chorus.  Where we fundamentally differ is in our view of what constitutes a fabric and how one implements that fabric.  Whereas Cisco is attempting to build a flatter, non-blocking network using their existing and evolving Nexus switches, we have focused on building a fabric by rethinking the concept of the switch.


These different approaches are best illustrated by how each company expresses the “key principles of a fabric.”  In the column on the left in the table below, I have listed the seven key principles of a fabric as defined in a paper published in February by Pradeep Sindhu, the founder of Juniper Networks and the architect behind QFabric.  In the column on the right are Cisco’s five key principles of a “Unified Fabric” as presented on slide 32 during the March 30 announcement.





1.    Any-to-any connectivity with fairness and full non-blocking behavior for all traffic in a data center


1.   Virtual Switches

2.    Low latency and jitter


2.   Hybrid Switches

3.    No packet drops under congestion


3.  Storage over Ethernet

4.    Linear cost and power scaling


4.  Flattening the network

5.   Support of virtual network and services


5.  A new set of network management capabilities

6.   Modular, distributed implementation that is highly scalable



7.   Single logical device




Notice that the list of principles on the left speaks to how a fabric should behave while the list on the right is more about “building” a fabric from specific existing components or capabilities.  This is a very clear delineation between the approaches each company has taken towards building a fabric.  The question is whether customers should care about these differences.   I would argue the answer is yes.  Here are three reasons why.


1.  The last principle on each list attempts to speak to operational simplicity.  Cisco specifies “a new set of network management capabilities” that, per slide 8 in their announcement, delivers “single pane of glass visibility across LAN and SAN.”  “Single pane of glass” is the term used to describe the ability to monitor and/or manage multiple separate devices from a single user client.  This does not necessarily make it simpler, just more convenient.  In Juniper’s case, QFabric is a single logical device that behaves like and is managed as such.  This is simpler and, we believe, fundamental to a fabric.  For customers, simpler is always better as it lowers OPEX and improves availability.


2.  Cisco introduced their new Broadcom-based Nexus 3000 for “low latency” deployments, primarily because all Nexus 5000s are notoriously slow.  However, the Nexus 3000 is not compatible with FabricPath or UCS, it does not support FCoE to FC gateway functionality, and it does not support their physical or virtual FEXs.  Thus you can be fast or you can be in a Cisco fabric, but you can’t be both.  We believe it is not a fabric unless it has low latency and low jitter.  For customers, faster is always better as it improves application behavior.


3.  Cisco announced their new ability to transport FCoE packets across a Nexus 7000.  However, that ability cannot use the FabricPath protocol.  Thus they offer a “unified fabric” for Layer 2 Ethernet traffic, a different fabric for FCoE traffic, and yet another distinct fabric for Layer 3 traffic.  It is not clear what part of the term "unified" they do not understand.  With QFabric, all traffic is inherently supported by the data path of the fabric and, for customers, one fabric is better as it simplifies operations and reduces cost.

The most important take away from the March 30 announcement is the reaffirmation that the fundamental architecture of the network must and will change in order to enable the promise of the virtualized data center.  Even Cisco now acknowledges that this evolution will require a wholesale replacement of most of the existing switching infrastructure as customers move from trees to fabrics.  The existing installed base of Catalyst switches in the data center will be replaced over the next five to 10 years.  The good news is that customers will have a rich set of alternatives to consider as they retool for the future.


by Abhijeet
on ‎04-06-2012 10:23 AM

Could someone please explain what a non-blocking network fabric is ?

First google search took me here, and nothing found.

PLease good guys at Juniper ! Help me Smiley Happy

by Distinguished Expert
on ‎04-06-2012 11:44 AM



By "non-blocking" they are talking about eliminating the need for spanning tree and therefore blocking ports when building out a large port count datacenter.  The current three tier architecture requires that there be redundant port connections for failover.  These then use spanning tree to block the duplicate port and prevent layer 2 loops.


A non-blocking fabric is able to create that redundancy without "wasting" ports by spanning tree blocks, but allowing all the ports to be used and having the redundant paths built into the fabric connections.


Check out this pdf on page 4 for the comparison of the traditional three tier datacenter reference architecture and the Q-fabric solution.  The rest of the document describes how the traditional switch is abstracted to multiple devices that allow this any port to any port connectivity without the use of spanning tree.


The Q-fabric product general information is here.


Steve Puluka BSEET
Senior Network Administrator
MCP 70-290 - Managing Server 2003
MCTS Windows 7


by Abhijeet
on ‎04-06-2012 10:22 PM

Thanks a lot Steve !

Juniper Networks Technical Books
About the Author
  • Prior to Juniper acquisition, Ankur was the Founder and CEO of Contrail Systems Inc - a pioneer in standards based network virtualization and scale-out networking software. Ankur has over 15 years of experience in building world-class networking products and leading high performance teams. Prior to Contrail, Ankur served as Chief Technology Officer and VP of Engineering at Aruba Networks, where he played critical roles in the rapid expansion of team, products, and global businesses. Before Aruba, Ankur helped drive Juniper’s initial entry into and expansion of the Ethernet Switching market. Ankur received his MSEE from Stanford University & BSEE from the University of Southern California.
  • I am an experienced leader in the Information Experience (iX) industry. For over 20 years, I've led information organizations at Juniper, Microsoft, Cisco, and Oracle to deliver quality technical documentation and information products to customers and partners across the globe.
  • Bob Dix currently serves as the Vice President of Government Affairs & Critical Infrastructure Protection for Juniper Networks. During his career, he has served in senior leadership roles in industry and government, including serving as Staff Director for the House Government Reform Subcommittee on Technology, Information Policy, Intergovernmental Relations and the Census during the 108th Congress. He represents Juniper on the Industry Executive Point of Contact for the President's National Security Telecommunications Advisory Committee ( NSTAC ), where he chaired the Cybersecurity Collaboration Task Force in 2009. He served as Chair of the Information Technology Sector Coordinating Council ( IT SCC ) from 2008 – 2010 and currently remains a member of the Executive Committee. Mr. Dix was elected in May, 2011 as Chair of the Partnership for Critical Infrastructure Security ( PCIS ). He also serves on the National Security Task Force for the U. S. Chamber of Commerce. He is a member of the AFCEA Cyber Security Committee and Chairs the Supply Chain Assurance Subcommittee for TechAmerica. Additionally, Dix has actively worked to insure and coordinate private sector participation and collaboration with the National Exercise Program, intended to test our nation’s preparedness and resiliency. He served as Chair of the National Private Sector Working Group for National Level Exercise 2011 and 2010. In 2007 and 2009, Dix was honored with a prestigious Federal 100 Award, and was recognized in March, 2010 as the recipient of the annual FCW Industry Eagle Award. Dix also served as a local government elected official in Northern Virginia for 12 years and in his spare time coaches AAU/Travel girls basketball.
  • Jennifer Blatnik is vice president of cloud, security and enterprise portfolio marketing at Juniper Networks with focus on enterprise deployments of security, routing, switching, and SDN products, as well as cloud solutions. She has more than 20 years of experience helping enterprises solve network security challenges. Before joining Juniper, Jennifer served multiple roles at Cisco Systems, Inc., including directing product management for security technologies aimed at small to medium enterprises, as well as supporting managed services, cloud service architectures and go-to-market strategies. She holds a B.A. in Computer Science from University of California, Berkeley.
  • Jerry oversees all aspects of OpenLab which serves as a catalyst to spark the development of new innovative software applications or solutions that leverage the power of SDN/network programmability and intelligence. OpenLab is unique within Juniper and with its polished facility, globally accessible lab, and educational programs – such as the SDN “hackathons,” it serves as a tool for customer, partners, and academia. Prior to this position, Jerry led the development, management and marketing of the company’s strategic partnerships for video/unified communications, optical networking, and content/media delivery. In addition to handling the day-to-day oversight of the partnerships, he established new cross-partner go-to-market processes to drive and manage joint field opportunities. Before joining Juniper, Jerry led the Lucent Technologies application hosting/service provider marketing organization. He has over 25 years of experience in the data networking field with a focus on strategic alliance development, marketing, and technical field support. Jerry possesses a BS degree in Computer Science from St. John’s University in New York. He is active as a Juniper ambassador within the technology and academic community which includes advisory board positions with both NJIT and Rutgers in New Jersey.
  • Kevin Walker is the Security Chief Technology and Strategy Officer for Juniper’s Development and Innovation (JDI) organization. He is responsible for driving the security strategy both internally within Juniper, and externally with investors, partners, influencers, and customers. He provides the guidance required for JDI to conceive, develop and create momentum for industry-leading security solutions. Working closely with the Security Engineering team, Walker identifies the opportunities for improved security, growth, and innovation to deliver the scalable, reliable, and compliant security architecture needed in today’s security landscape. Before joining Juniper, Walker was VP and Assistant Chief Information Security Officer (CISO) at He has served as a Chief Information Security Officer (CISO), Chief Security Strategist and Director of Information Security across a number of notable companies including Intuit, Cisco, Symantec and VERITAS Software. With over twenty-five years in various computer science and information technology disciplines, focusing on enterprise applications, network design, and information security, Walker possesses research and engineering expertise across of range of technologies including networking protocols, securing applications at the atomic level, cryptography, and speech biometrics.
  • As Juniper’s Senior Vice President of Strategy and Product Line Management, Kevin Hutchins is responsible for defining and enabling Juniper’s strategy from company vision into product execution. This includes driving the company’s inorganic growth through strategic partnerships, venture investments and acquisitions/divestitures. In addition, he is responsible for driving key strategic imperatives, including Juniper’s software strategy and transformation. Hutchins joined Juniper in 2010 as Vice President, Portfolio Management & Business Operations for Juniper’s Development & Innovation team where he led business planning, portfolio rationalization, new product introduction and execution of strategic programs across Juniper’s portfolio of routing, switching and security products.
  • Mike Marcellin is Senior Vice President and Chief Marketing Officer, leading the global marketing team responsible for marketing Juniper’s product and services portfolio and stewarding the brand, driving preference for Juniper in the market, training our partners and account teams, and developing a differentiated information experience for our customers. Before joining the global marketing organization, Marcellin led business strategy and marketing for Juniper’s industry-leading portfolio of high-performance routing, switching and security products. Prior to joining Juniper in 2010, Marcellin served as Vice President of Global Managed Solutions for Verizon, where he oversaw product development and marketing of its managed IP networking, hosting, security and IT solutions for businesses around the world. He also served as Vice President of Global Product Marketing for Verizon Business, executive director of Verizon Business’ IP and Ethernet portfolio as well as leading the company’s eCRM marketing division. Marcellin began his career with MCI in 1994. Marcellin is a Board Member for the Telecommunications Industry Association and a Board Member of US Ignite, an NSF-sponsored initiative. Marcellin holds two patents and was a Rodman Scholar at the University of Virginia, where he received a bachelor of science degree with distinction in systems engineering. He is based in Sunnyvale, California.
  • Masum Mir is Vice President of Product, Solutions & Technical Marketing at Juniper Networks. Masum is responsible for the Switching product line, network management product line and optical technologies. Beside product leadership Masum also leads cloud strategy and solution architecture. Masum has 19 years of experience in communication and data networking industry with Expertise in Ethernet Switching, Data Center, Carrier Ethernet, Routing, overlay & network segmentation, Fabric technology & photonics technology.
  • Paul Obsitnik is Vice President of Service Provider Marketing for Juniper Networks Platform Systems Division (PSD), responsible for the marketing of Juniper’s portfolio of high performance routing, switching, and data center fabric products to Service Providers globally. Paul's team is responsible for marketing strategy, product marketing, go-to-market planning, and competitive analysis worldwide for the Service Provider segment. Obsitnik has extensive experience in marketing, sales and business development positions with a proven track record in creating technology markets. He has served in senior marketing and sales management positions at several companies including BridgeWave Communications, ONI Systems, NorthPoint Communications and 3Com. Paul holds a Bachelor of Science with Honors in Electrical Engineering from the United States Naval Academy and a Master of Business Administration from the Harvard Graduate School of Business. Obsitnik is based in Sunnyvale, California.
  • Pradeep Sindhu founded Juniper Networks in February 1996, and has held several central roles in shaping the company. He currently serves as Vice Chairman of the Board and Chief Technology Officer, and is responsible for the company's technical roadmap as well as day-to-day design and development of future products. He served as Chairman and Chief Executive Officer for eight months when he founded the company. During that time, he played a central role in the architecture, design, and development of the M40 router.
  • Rami Rahim is Chief Executive Officer of Juniper Networks and a member of the company’s Board of Directors. Rahim was appointed CEO in November 2014. Rahim began his Juniper career in early 1997, as employee No. 32, and worked as an engineer on Juniper’s first breakthrough product, the M40 core router. Rahim has progressed through a series of technical and leadership roles at Juniper, applying his engineering acumen to the design and development of Juniper’s industry-leading product portfolio. He most recently served as Executive Vice President and General Manager of the Juniper Development and Innovation (JDI) organization, overseeing the company’s entire product and technology portfolio. His responsibilities included driving strategy, development and business growth for routing, switching, security, silicon technology, and the Junos operating system. Other leadership positions held over the years include: Executive Vice President and General Manager of Platform Systems Division for routing and switching, Senior Vice President of the Edge and Aggregation Business Unit (EABU), and Vice President and General Manager of EABU.
  • As Chief Customer Officer, Vince Molinaro is responsible for driving the strategic and operational elements of the Sales, Marketing, Partners, Services and Support functions at Juniper Networks. He leads a global organization of more than 3,500 professionals that includes direct and indirect sales, systems engineering, advanced technologies and field operations. Molinaro brings more than 25 years of professional experience in engineering, product management, marketing, sales and operations to his worldwide role. He joined Juniper in 2009 and led the strategy and go-to-market execution for the company’s global service provider business. He was named EVP, Worldwide Sales in 2013 before assuming his current role in February 2014. Prior to joining Juniper, Molinaro held senior leadership positions at a number of technology companies including Bell Laboratories, Lucent Technologies, Alcatel-Lucent and Internap Network Services. He has extensive domestic and international experience having lived and managed large organizations throughout Europe and the U.S. Molinaro holds a bachelor of science degree in biomedical engineering from Boston University and a master of science degree in electrical engineering from University of Bridgeport. He is based out of the Juniper Networks facility in New Jersey, home of OpenLab, The Junos and SDN Center for Innovation.
About The New Network

Exploring the vision for the networking industry and the issues shaping its future.

Subscribe to The New Network    RSS Icon

Our Bloggers

Rami Rahim
Chief Executive Officer

Profile | Subscribe

Pradeep Sindhu
Vice Chairman of the Board & CTO

Profile | Subscribe

Mike Marcellin
Chief Marketing Officer

Profile | Subscribe

Ankur Singla
Vice President of Engineering

Profile | Subscribe

Bob Dix
Vice President
Government Affairs &
Critical Infrastructure Protection

Profile | Subscribe