CREATING A MODERN CAMPUS AREA NETWORK: A ‘HOW TO’ GUIDE

Without question, Open Networking and SDN have altered the landscape of data center networks irrevocably. Less than a decade has elapsed since Facebook open-sourced its hardware designs for its Prineville, Oregon data center and formed the Open Compute Project (OCP). One month previous, the Open Networking Foundation (ONF) had formed to promote the benefits of SDN and the OpenFlow protocol. These two organizations, with more than a little help from companies like Facebook, Google, and Microsoft, have presided over a shift that has massively reduced CAPEX and OPEX, improved scalability, automation, and efficiency and has given the power back to companies to determine what is the best fit for their particular need.

Originally, these organizations concentrated on the data center market, but since 2016 they have adjusted their focus to include the telecoms and enterprise markets. The Telecom Infra Project, founded in 2016, has gone from strength to strength in bringing the benefits of the disaggregated data center model to the telecoms industry with products like the Cassini transponder or the Disaggregated Cell Site Gateway from Edgecore.

Enterprise and campus networks are the next areas of networking that is going to benefit from the model that has completely altered data centers. Cumulus Networks are bringing open networking, with all its innovation and cost efficiencies to the campus network space in what they are calling, “Modern Campus”.

WHO IS CUMULUS NETWORKS?

Cumulus Networks is a software company that was founded in 2010 by JR Rivers and Nolan Leake. They have been at the forefront of open networking since its foundation, with Gartner highlighting them as a “pioneer of open source networking”. They have two main products which are Cumulus Linux, a Debian based Linux network operating system (NOS), and NetQ, which provides real-time telemetry and fabric-wide analytics. Cumulus also initiated the Open Network Install Environment (ONIE) project. ONIE comes preloaded on every bare metal switch and allows for the NOS, like Cumulus Linux, to be installed.

Cumulus has had great success in the open networking market, supporting more than 1500 customers worldwide and 35% of the Fortune 50. Not too shabby!! They also support more hardware vendors than any other software with over 130 platforms from the likes of Edgecore, Quanta, and Delta et al. Cumulus is now looking to redefine the boundaries of open networking in the campus space. Read on to find out a little about campus networks and what is the Cumulus proposition here.

WHAT IS A CAMPUS AREA NETWORK (CAN)?

When first hearing the term campus network the mind immediately conjures images of a university or a college, while not wrong, it doesn’t give the full impression of what it is describing. A campus network sits between a local area network (LAN) and a metro area network (MAN) in size. It can be described as multiple LANs connected over a small(ish) geographic area. This can incorporate enterprise, government, schools and of course, colleges and universities. The hardware involved on the networking side is switches and routers with fiber-optic (preferably) or copper cabling. Even though the CAN can (everybody dances!) be spread over multiple kilometers geographically, the networking equipment is usually owned by the campus itself.

Despite the clear benefits of open networking, there has been slow deployment in the enterprise and campus sector to date. The main reasons for this were concerns about service and support, implementation worries, and most importantly, the lack of a real market leader. Many of the software vendors dabbled in this area without really making the commitment that was needed. If the vendor does not show complete confidence it is understandable that you would have an apathetic customer base. Cumulus Networks have now made the commitment that was required to get the ball rolling, and take campus fabric design to the next level.

CUMULUS’S MODERN CAMPUS

Cumulus Linux is the industry-leading, open, data center NOS and it’s this success that has steered them into the campus market. Requests were made from their own customer base to add the enterprise feature set that would allow companies to not only run their data center with Cumulus but the campus fabric too. The same monitoring and operational tools in use for their Linux systems in the data center can now be used for the campus network also. Some of the new features added to Cumulus Linux:

• BGP, OSPF, and multicast for L3
• Spanning Tree Protocol (STP) for L2
• Time Domain Reflectometer (TDR) for L1
• Port security
• VXLAN and BGP-EVPN for campus fabric
• TACACS, LDAP, and RADIUS for authentication
• 802.1X interfaces with change of authorization (CoA)
• Network Command Line Utility (UCLI), CLI with tab complete and commit/rollback
• SNMPv2c/v3
• Multigigabit
• Power over Ethernet (PoE)

Cumulus also offers visibility into the network fabric in real-time with its NetQ analytics and telemetry server. This all in one tool simplifies troubleshooting, heightens visibility, and enriches existing monitoring and operational strategies. NetQ comes with a GUI, a CLI and RESTful API that allows you to retrieve data in real-time or in the past. Additionally, NetQ can be installed on your Linux servers to extend your overall visibility. The Cumulus NetQ agent is simply installed on a bare-metal Linux host or even inside a Linux VM.

Within the data center, Cumulus works best in a Clos (spine and leaf) or fat-tree topology. This is different from the traditional three-tiered hierarchical model used in the campus that contains 3 distinct layers, core, distribution, and access. For larger deployments, we will usually see these 3 layers but in smaller ones, we may see core and distribution collapsed into one layer. There are not really any hard and fast rules once your network suits the use case. Below the image, there are a few helpful considerations to use during the planning phase.

THINGS YOU SHOULD CONSIDER WHEN CREATING A MODERN CAMPUS AREA NETWORK

• Existing Infrastructure – Cat6 cables allow for speeds up to 10Gbps and Cat5e up to 1Gbps. Features like 802.3bz allow Cat5e to reach 2.5Gbps and Cat6 5Gbps.
• Scalability – Making a concession in the design phase for future scalability can often pay dividends. Allowing room to grow is essential.
• Budget – The budget will always drive decision making. Do not let this stop you from building a highly redundant network.
• Security – This needs to be looked at early in the process. Security best practices and regulatory compliance can create design problems when segmenting the network.
• Management and operations – How easy is it to manage the network devices? Can changes be made easily and quickly? Is it easy to monitor the devices and how easy is it to troubleshoot when things do go wrong? These are some of the questions that should be asked in the early stages of planning.

This was a quick first look at campus networks from Cumulus. In an upcoming blog, I will take a closer look at the hardware involved from Edgecore Networks and others. We will also take a more focused look at the three-tiered architecture and the possibilities when it comes to the network design.

For more information on products and services related to Open Networking come check out our website at www.epsglobal.com. Next in the Open Networking Series, we will be taking a deeper dive into the world data center fabrics.

Slán go fóill,

Barry