Welcome!

SDN Journal Authors: Pat Romanski, David Paquette, Liz McMillan, Olivier Huynh Van, Mark Hoover

Related Topics: SDN Journal, Microservices Expo, Containers Expo Blog, @CloudExpo, Cloud Security, @BigDataExpo

SDN Journal: Blog Post

Aggregation Is Good. Aggregation Is Bad.

The vast majority of networking equipment is driven by specialized hardware

For as long as I remember networking has struggled with the balance between aggregated and individual traffic flows. Following the abilities of the technology components we use, we have been forced to aggregate, only to be allowed to de-aggregate or skip aggregation when technology caught up or surpassed the needs of today.

The vast majority of networking equipment is driven by specialized hardware. For datacenter switches, speed and port density are driving the requirements and physics and our technology capabilities create trade-offs that ultimately lead to some form of aggregation. Higher speed and more ports are traded off against memory, table space and functionality. These trade-offs will always exist, no matter what we are trying to build. Networking based in servers will have oodles of memory and table space to do very specific things for many many flows, making it extremely flexible, but those same servers cannot touch the packet processing speeds of the specialized packet processing hardware from Broadcom, Intel or Marvell, or the custom ASICs from Cisco, Juniper, or most anyone else.

funnelSo like it or not, we will want to do more than our hardware is capable of and as a result, we create aggregation points in the network where we lump a bunch of flows together into an aggregate flow and start making decisions on those. Nothing new, even good ole IP forwarding is doing so on an aggregate set of flows, it only makes decisions for all flows destined to a specific IP address.

Network tunnels are the most obvious examples of aggregation, their purpose is to hide information from intermediate networking equipment. In some cases we hide it to keep our table sizes under control, in some cases we hide it because we do not want the intermediate equipment to be able to see what we are transporting (IPSec, SSL, etc). And while sometimes the intermediate systems can see everything that is there, managing the complexity of that visibility simply becomes too expensive. This is why networks that are entirely managed and controlled per flow do not really exist at any reasonable scale, and probably never will.

For the exact same reason we aggregate, we lose the ability to act on specifics. When our tables are not large enough to track each and every flow, we can only make decisions based on what we have decided to keep in common. When talking about tunnels, the tunnel endpoints put new headers onto the original packets and intermediate systems can only act (with minor exceptions) on the information provided in these new headers. The original detail is still there and often visible to the intermediate system, but the intermediate system does not have the capacity to act on the sheer volume of that detail.

And there is the struggle. If I have more information, I can make better decisions. But when I aggregate because I cannot handle that extra information (due to sheer size or management complexity), my decisions by definition become more coarse and as a result, less accurate. But we want it all. We want the power to make decisions based on the most specific information we can, but want to aggregate for operational simplicity or because our hardware dictates. And this is where we get creative and start to turn what used to be black and white into gray.

There is nothing wrong with attempting to act on specifics for aggregate flows, but in so many cases its done as an afterthought and becomes hard to manage, control or specify. Some of the techniques we use are fairly clean, like taking the DSCP values from a packet and replicating it in the outer header of that same packet in a tunnel. Others are far more obscure like calculating some hash function on a packet header and using it as the UDP source port for the VXLAN encapsulated version of that packet. In even others, the original internals may be completely invisible to intermediate systems. STT for instance re-uses the format of TCP packets for its own purpose, but as a side effect of using it as a streaming-like protocol is that the original packet headers may not actually be in an IP packet on the wire. The STT header provides for a 64 bit Context-ID that can be used to take some bits of information from the original packet, but that STT header only appears in the first of what could be many individual packets that are re-assembled in the receiving NIC. Over the Christmas break I spent some time looking at each of the overlay formats and the tools modern day packet processors give you to act on these headers. I will share some of this in this forum next week.

Ultimately, overlay networks are creating a renewed emphasis on the choices between aggregation and individuality. Designed specifically to allow for more complex and scaled networks that hide a lot of the details from the dedicated network hardware, it comes with the price of less granular decisions by that hardware, which can certainly lead to less than optimal use of the available network.

[Today's fun fact: In the Netherlands, there is a 40% higher chance of homeowner insurance claims on the home owner's birthday. Those are some good parties.]

The post Aggregation is Good. Aggregation is Bad. appeared first on Plexxi.

Read the original blog entry...

More Stories By Marten Terpstra

Marten Terpstra is a Product Management Director at Plexxi Inc. Marten has extensive knowledge of the architecture, design, deployment and management of enterprise and carrier networks.

@CloudExpo Stories
In his general session at 18th Cloud Expo, Lee Atchison, Principal Cloud Architect and Advocate at New Relic, discussed cloud as a ‘better data center’ and how it adds new capacity (faster) and improves application availability (redundancy). The cloud is a ‘Dynamic Tool for Dynamic Apps’ and resource allocation is an integral part of your application architecture, so use only the resources you need and allocate /de-allocate resources on the fly.
Your business relies on your applications and your employees to stay in business. Whether you develop apps or manage business critical apps that help fuel your business, what happens when users experience sluggish performance? You and all technical teams across the organization – application, network, operations, among others, as well as, those outside the organization, like ISPs and third-party providers – are called in to solve the problem.
Information technology is an industry that has always experienced change, and the dramatic change sweeping across the industry today could not be truthfully described as the first time we've seen such widespread change impacting customer investments. However, the rate of the change, and the potential outcomes from today's digital transformation has the distinct potential to separate the industry into two camps: Organizations that see the change coming, embrace it, and successful leverage it; and...
SYS-CON Events announced today that Roundee / LinearHub will exhibit at the WebRTC Summit at @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LinearHub provides Roundee Service, a smart platform for enterprise video conferencing with enhanced features such as automatic recording and transcription service. Slack users can integrate Roundee to their team via Slack’s App Directory, and '/roundee' command lets your video conference ...
A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, wh...
Digital transformation is too big and important for our future success to not understand the rules that apply to it. The first three rules for winning in this age of hyper-digital transformation are: Advantages in speed, analytics and operational tempos must be captured by implementing an optimized information logistics system (OILS) Real-time operational tempos (IT, people and business processes) must be achieved Businesses that can "analyze data and act and with speed" will dominate those t...
The Jevons Paradox suggests that when technological advances increase efficiency of a resource, it results in an overall increase in consumption. Writing on the increased use of coal as a result of technological improvements, 19th-century economist William Stanley Jevons found that these improvements led to the development of new ways to utilize coal. In his session at 19th Cloud Expo, Mark Thiele, Chief Strategy Officer for Apcera, will compare the Jevons Paradox to modern-day enterprise IT, e...
There are several IoTs: the Industrial Internet, Consumer Wearables, Wearables and Healthcare, Supply Chains, and the movement toward Smart Grids, Cities, Regions, and Nations. There are competing communications standards every step of the way, a bewildering array of sensors and devices, and an entire world of competing data analytics platforms. To some this appears to be chaos. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Bradley Holt, Developer Advocate a...
More and more companies are looking to microservices as an architectural pattern for breaking apart applications into more manageable pieces so that agile teams can deliver new features quicker and more effectively. What this pattern has done more than anything to date is spark organizational transformations, setting the foundation for future application development. In practice, however, there are a number of considerations to make that go beyond simply “build, ship, and run,” which changes ho...
SYS-CON Events announced today the Kubernetes and Google Container Engine Workshop, being held November 3, 2016, in conjunction with @DevOpsSummit at 19th Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA. This workshop led by Sebastian Scheele introduces participants to Kubernetes and Google Container Engine (GKE). Through a combination of instructor-led presentations, demonstrations, and hands-on labs, students learn the key concepts and practices for deploying and maintainin...
Without a clear strategy for cost control and an architecture designed with cloud services in mind, costs and operational performance can quickly get out of control. To avoid multiple architectural redesigns requires extensive thought and planning. Boundary (now part of BMC) launched a new public-facing multi-tenant high resolution monitoring service on Amazon AWS two years ago, facing challenges and learning best practices in the early days of the new service. In his session at 19th Cloud Exp...
SYS-CON Events announced today that Bsquare has been named “Silver Sponsor” of SYS-CON's @ThingsExpo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. For more than two decades, Bsquare has helped its customers extract business value from a broad array of physical assets by making them intelligent, connecting them, and using the data they generate to optimize business processes.
SYS-CON Events announced today that ReadyTalk, a leading provider of online conferencing and webinar services, has been named Vendor Presentation Sponsor at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. ReadyTalk delivers audio and web conferencing services that inspire collaboration and enable the Future of Work for today’s increasingly digital and mobile workforce. By combining intuitive, innovative tec...
There is growing need for data-driven applications and the need for digital platforms to build these apps. In his session at 19th Cloud Expo, Muddu Sudhakar, VP and GM of Security & IoT at Splunk, will cover different PaaS solutions and Big Data platforms that are available to build applications. In addition, AI and machine learning are creating new requirements that developers need in the building of next-gen apps. The next-generation digital platforms have some of the past platform needs a...
While DevOps promises a better and tighter integration among an organization’s development and operation teams and transforms an application life cycle into a continual deployment, Chef and Azure together provides a speedy, cost-effective and highly scalable vehicle for realizing the business values of this transformation. In his session at @DevOpsSummit at 19th Cloud Expo, Yung Chou, a Technology Evangelist at Microsoft, will present a unique opportunity to witness how Chef and Azure work tog...
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
Fact is, enterprises have significant legacy voice infrastructure that’s costly to replace with pure IP solutions. How can we bring this analog infrastructure into our shiny new cloud applications? There are proven methods to bind both legacy voice applications and traditional PSTN audio into cloud-based applications and services at a carrier scale. Some of the most successful implementations leverage WebRTC, WebSockets, SIP and other open source technologies. In his session at @ThingsExpo, Da...
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, will discuss the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports. The session will include a working demo and a technical d...
Almost two-thirds of companies either have or soon will have IoT as the backbone of their business in 2016. However, IoT is far more complex than most firms expected. How can you not get trapped in the pitfalls? In his session at @ThingsExpo, Tony Shan, a renowned visionary and thought leader, will introduce a holistic method of IoTification, which is the process of IoTifying the existing technology and business models to adopt and leverage IoT. He will drill down to the components in this fra...
I'm a lonely sensor. I spend all day telling the world how I'm feeling, but none of the other sensors seem to care. I want to be connected. I want to build relationships with other sensors to be more useful for my human. I want my human to understand that when my friends next door are too hot for a while, I'll soon be flaming. And when all my friends go outside without me, I may be left behind. Don't just log my data; use the relationship graph. In his session at @ThingsExpo, Ryan Boyd, Engi...