Terry Slattery
Terry Slattery, is a senior network engineer with decades of experience in the internetworking industry. Prior to joining Chesapeake NetCraftsmen as...
Read Full Bio >>

Terry Slattery | November 15, 2017 |


Verify Intended Network Functionality Using Veriflow

Verify Intended Network Functionality Using Veriflow What kinds of problems would you be able to avoid by managing your network according to your intent?

What kinds of problems would you be able to avoid by managing your network according to your intent?

Here's the problem: You're responsible for a network and would like an automatic way to verify that it's functioning correctly. Validation is important for business applications as well as for voice and collaboration, especially with regard to security and redundancy.

Traditional network management systems rarely contain the types of checks needed to discern correct operation. Sure, they check interface up/down, memory/CPU utilization, interface utilization/congestion. But these are device-centric checks, not system-level checks. Some advanced management systems check multi-device functions like Hot Standby Routing Protocol (HSRP) or Spanning Tree Protocol (STP), but that doesn't necessarily mean that they also check that the network is performing correctly or that redundant paths are operational.

When I say "performing correctly," I mean that business applications are able to communicate with one another to implement business processes and to provide desired resiliency for various failures. Preventing and restricting communications is just as important, but network management systems rarely provide such functionality. Should the air conditioning system really be communicating with the voice and collaboration systems? That's not something most network management systems would be capable of detecting -- or taking action on to remediate.

One Solution
Veriflow offers one possible solution, as CEO James Brear explained at last month's Networking Field Day 16 (NFD16).

You may have recently read about intent-based networking (IBN) here on No Jitter or elsewhere (see my post, "Intent-Based Networking: Buzzword or Real?). IBN systems verify that the network is correctly implementing its design intent, including connectivity, link operation, security policies, routing policies, and redundancy. Managing by intent is a good way to find hidden problems, as well as to verify functionality after changes.

In a Veriflow-commissioned survey, Dimensional Research found organizations that run validation checks (some don't) primarily used several mechanisms to verify their networks (multiple responses allowed):

  • Manual process (69%)
  • Network management system (57%)
  • Scripts (47%)
  • Commercial products (12%)

Validating network functionality requires:

  1. Data from the network about how the network is functioning
  2. Rules and policy definitions that check the data against the desired functionality

Veriflow automates the collection of network data with minimal configuration required. On the other hand, functional validation requires entering rules that define the checks to be performed. Veriflow's application programming interfaces (APIs) allow network managers to automate any aspect of the system as applicable to their needs or to extend the system's analysis with external data processing.

The Details
Veriflow includes a topology mapping function with basic Layer 2 and Layer 3 layout. As with any topology mapping tool, you'll have to manually edit the diagrams to make them look good or to match them up with your concept of the topology. The network discovery mechanism also works in Amazon Web Services (with support planned for Microsoft Azure and Google Cloud Platform).

Basic analysis rules provide information on devices that are added and removed from the network, something that most network management systems can perform. It can also do firewall rule analysis by looking at the forwarding plane state information and tracking flows across the network. So, it can validate whether two endpoints or subnets can communicate with one another.

In the NFD demonstration, Veriflow showed an example of an incorrectly configured firewall -- it was supposed to have redundant paths to two core routers, but in fact had only one active connection. As such, when the operational path went down, an outage would have resulted. The topology map showed the existing connectivity, making the absence of a redundant path obvious. Think about how useful that would be for checking the resiliency of a voice/video system or critical business application.

A recent addition to the product uses configuration data it pulls from network devices to perform "pre-flight" analysis of connectivity based on proposed configuration changes. Being able to verify proposed configurations before deploying them in a live, production network will help reduce configuration errors.

The data collection system is separate from the analysis and rules engine. Data collection agents run either on or near the network devices, while the analysis engine sits in the cloud or, for organizations that can't export data to a cloud analysis system, it runs on on-premises servers.

With APIs, Veriflow offers the ability to extend the product's functionality.

Real-World Application
How would I apply Veriflow in a real network? I would start with the network discovery and topology mapping. Having accurate topology maps is always a good thing -- a good topology map will tell you whether the network is actually connected the way you think it is, but never had the time to verify.

I would then review my network documentation and enter simple rules that verify the infrastructure links. For example, Switch A, Gig0/1 should connect to Switch B, Gig0/48. Veriflow can then generate alerts whenever there is a problem with a connection, including basic cabling errors. This is where a separate source of truth database (i.e., NSoT or NetBox) can be handy as a repository for connectivity and addressing information. While I would start with the infrastructure links (router and switch interconnects), I would quickly add critical server interfaces for business application servers and UC infrastructure.

Next I would start adding connectivity rules for business applications, voice, video, and collaboration. A quick review of IT trouble tickets should provide enough information to identify rules to add. Examining security policies and application connectivity requirements would be the next step.

Veriflow looks to be a quick install with relatively easy configuration and rapid results. A proof-of-concept test should be easy to perform. The greater challenge for most organizations will be to identify the network design intent and create the corresponding Veriflow connectivity rules.

I'm starting to see several networking tools that provide system-level functionality. Veriflow is one that can be applied to a variety of network topologies, such as leaf-spine and three-tier (core, distribution, access) models. I'm looking forward to more of these tools and exploring how to integrate them with one another.

Disclosure and caveat: While the NFD presenters indirectly paid for my travel and lodging to attend NFD16, I didn't receive any compensation nor have the vendors been promised any favored treatment in articles or reviews. I've not yet had an opportunity to drive Veriflow in a real network, so the above information is from the NFD16 presentation and a follow-up presentation at NetCraftsmen.

Learn more about Systems Management & Network Design at Enterprise Connect 2018, March 12 to 15, in Orlando, Fla. Register now using the code NOJITTER to save an additional $200 off the Advance Rate or get a free Expo Plus pass.

Related content:


October 24, 2018

With disparate workplaces and ever-expanding volumes of information to manage, the challenges for collaborating effectively are only intensifying. Many critical applications are not integrated, and

October 10, 2018

Businesses are growing across international borders quicker than ever, but scaling operations to follow suit can be a harder, longer process.

This webinar focuses on scaling your next-generat

September 26, 2018

Join Kevin Kieller, Microsoft UC&C expert, along with Ribbon Communications and Polycom, for an update on Microsoft Ignite, and a focus on critical things you need to know about your voice deployme

March 12, 2018
An effective E-911 implementation doesn't just happen; it takes a solid strategy. Tune in for tips from IT expert Irwin Lazar, of Nemertes Research.
March 9, 2018
IT consultant Steve Leaden lays out the whys and how-tos of getting the green light for your convergence strategy.
March 7, 2018
In advance of his speech tech tutorial at EC18, communications analyst Jon Arnold explores what voice means in a post-PBX world.
February 28, 2018
Voice engagement isn't about a simple phone call any longer, but rather a conversational experience that crosses from one channel to the next, as Daniel Hong, a VP and research director with Forrester....
February 16, 2018
What trends and technologies should you be up on for your contact center? Sheila McGee-Smith, Contact Center & Customer Experience track chair for Enterprise Connect 2018, gives us the lowdown.
February 9, 2018
Melanie Turek, VP of connected work research at Frost & Sullivan, walks us through key components -- and sticking points -- of customer-oriented digital transformation projects.
February 2, 2018
UC consultant Marty Parker has crunched lots of numbers evaluating UC options; tune in for what he's learned and tips for your own analysis.
January 26, 2018
Don't miss out on the fun! Organizer Alan Quayle shares details of his pre-Enterprise Connect hackathon, TADHack-mini '18, showcasing programmable communications.
December 20, 2017
Kevin Kieller, partner with enableUC, provides advice on how to move forward with your Skype for Business and Teams deployments.
December 20, 2017
Zeus Kerravala, principal analyst with ZK Research, shares his perspective on artificial intelligence and the future of team collaboration.
December 20, 2017
Delanda Coleman, Microsoft senior marketing manager, explains the Teams vision and shares use case examples.
November 30, 2017
With a ruling on the FCC's proposed order to dismantle the Open Internet Order expected this month, communications technology attorney Martha Buyer walks us through what's at stake.
October 23, 2017
Wondering which Office 365 collaboration tool to use when? Get quick pointers from CBT Nuggets instructor Simona Millham.
September 22, 2017
In this podcast, we explore the future of work with Robert Brown, AVP of the Cognizant Center for the Future of Work, who helps us answer the question, "What do we do when machines do everything?"
September 8, 2017
Greg Collins, a technology analyst and strategist with Exact Ventures, delivers a status report on 5G implementation plans and tells enterprises why they shouldn't wait to move ahead on potential use ....
August 25, 2017
Find out what business considerations are driving the SIP trunking market today, and learn a bit about how satisfied enterprises are with their providers. We talk with John Malone, president of The Ea....
August 16, 2017
World Vision U.S. is finding lots of goodness in RingCentral's cloud communications service, but as Randy Boyd, infrastructure architect at the global humanitarian nonprofit, tells us, he and his team....
August 11, 2017
Alicia Gee, director of unified communications at Sutter Physician Services, oversees the technical team supporting a 1,000-agent contact center running on Genesys PureConnect. She catches us up on th....
August 4, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, has lately been working on integrating enterprise communications into Internet of Things ecosystems. He shares examples and off....
July 27, 2017
Industry watcher Elka Popova, a Frost & Sullivan program director, shares her perspective on this acquisition, discussing Mitel's market positioning, why the move makes sense, and more.
July 14, 2017
Lantre Barr, founder and CEO of Blacc Spot Media, urges any enterprise that's been on the fence about integrating real-time communications into business workflows to jump off and get started. Tune and....
June 28, 2017
Communications expert Tsahi Levent-Levi, author of the popular blog, keeps a running tally and comprehensive overview of communications platform-as-a-service offerings in his "Choosing a W....
June 9, 2017
If you think telecom expense management applies to nothing more than business phone lines, think again. Hyoun Park, founder and principal investigator with technology advisory Amalgam Insights, tells ....
June 2, 2017
Enterprises strategizing on mobility today, including for internal collaboration, don't have the luxury of learning as they go. Tony Rizzo, enterprise mobility specialist with Blue Hill Research, expl....
May 24, 2017
Mark Winther, head of IDC's global telecom consulting practice, gives us his take on how CPaaS providers evolve beyond the basic building blocks and address maturing enterprise needs.
May 18, 2017
Diane Myers, senior research director at IHS Markit, walks us through her 2017 UC-as-a-service report... and shares what might be to come in 2018.
April 28, 2017
Change isn't easy, but it is necessary. Tune in for advice and perspective from Zeus Kerravala, co-author of a "Digital Transformation for Dummies" special edition.
April 20, 2017
Robin Gareiss, president of Nemertes Research, shares insight gleaned from the firm's 12th annual UCC Total Cost of Operations study.
March 23, 2017
Tim Banting, of Current Analysis, gives us a peek into what the next three years will bring in advance of his Enterprise Connect session exploring the question: Will there be a new model for enterpris....
March 15, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, discusses the evolving role of the all-important session border controller.
March 9, 2017
Organizer Alan Quayle gives us the lowdown on programmable communications and all you need to know about participating in this pre-Enterprise Connect hackathon.
March 3, 2017
From protecting against new vulnerabilities to keeping security assessments up to date, security consultant Mark Collier shares tips on how best to protect your UC systems.
February 24, 2017
UC analyst Blair Pleasant sorts through the myriad cloud architectural models underlying UCaaS and CCaaS offerings, and explains why knowing the differences matter.
February 17, 2017
From the most basics of basics to the hidden gotchas, UC consultant Melissa Swartz helps demystify the complex world of SIP trunking.
February 7, 2017
UC&C consultant Kevin Kieller, a partner at enableUC, shares pointers for making the right architectural choices for your Skype for Business deployment.
February 1, 2017
Elka Popova, a Frost & Sullivan program director, shares a status report on the UCaaS market today and offers her perspective on what large enterprises need before committing to UC in the cloud.
January 26, 2017
Andrew Davis, co-founder of Wainhouse Research and chair of the Video track at Enterprise Connect 2017, sorts through the myriad cloud video service options and shares how to tell if your choice is en....
January 23, 2017
Sheila McGee-Smith, Contact Center/Customer Experience track chair for Enterprise Connect 2017, tells us what we need to know about the role cloud software is playing in contact centers today.