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Application Performance Management

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APM Authors: Stackify Blog, Andreas Grabner, Carmen Gonzalez, Liz McMillan, Mehdi Daoudi

Related Topics: Continuous Integration, Application Performance Management (APM), DevOps Journal


How to Optimize TCP | @DevOpsSummit @Catchpoint #DX #DevOps #WebPerf

The aim of the modern web is to provide consumers with an excellent user experience by loading web content quickly & seamlessly

Optimize TCP to Speed Through the Digital Freeway
By Dhanush Suhas

TCP (Transmission Control Protocol) is a common and reliable transmission protocol on the Internet. TCP was introduced in the 70s by Stanford University for US Defense to establish connectivity between distributed systems to maintain a backup of defense information. At the time, TCP was introduced to communicate amongst a selected set of devices for a smaller dataset over shorter distances.

As the Internet evolved, however, the number of applications and users, and the types of data accessed and stored also evolved. The original intent of TCP was to communicate data in the form of text across computers; today’s data transfer is more complex including high pixel images, audio files, and video delivery.

The aim of the modern web is to provide consumers with an excellent user experience by loading web content quickly and seamlessly. This can be achieved by faster transmission of content over the Internet. TCP has evolved over the years and the protocol enhancements have made it possible to transmit several types of data content with optimal performance for all users.

In this article, we talk about three protocol enhancements made to TCP to have content delivered at a better rate:

  • Multipath TCP
  • TCP Connection and Session reuse
  • TCP Slow Start

To appreciate the benefits of these optimizations, it’s necessary to understand the design and some of the drawbacks of the older version.

TCP Connection
For data to be communicated reliably and in the right sequence between two systems, TCP must initially establish a connection between them. Once the connection is established, TCP determines how to break down the data that needs to be sent over the network.

TCP was initially designed to establish communication after a successful three-way handshake between the client and server (See Diagram below). Along with the three-way handshake, the client and server also exchange security information in the form of certificates. These certificates authorize the client to set up a secure communication, consuming additional network time during reconnection tries in cases of connection breakdowns.

Drawback #1: Network Switching
When a mobile device streaming live content over a Wi-Fi network goes out of range, the device switches to its mobile carrier. In this scenario, TCP needs to repeat the three-way handshake and the security information exchange once again; in the process, the device drops the existing Wi-Fi connection. The multipath feature was enabled to overcome the drawback of network switching.

Multipath TCP
Multipath TCP has capabilities to enable multiple sub-flows in a single TCP session. For example, consider two separate networks – Network 1 and Network 2. The server can send data over wireless Network 1 and re-establish the connection with wireless Network 2 if Network 1 is unavailable. The network switch is done without dropping the existing connection, which eliminates the additional overhead of TCP connection time.

To understand multipath TCP better, let’s look at connection and session reuse, which is used to speed up TCP time.

Connection and Session Reuse
Once a connection is established between the client and server using the three-way handshake, the connection can be used to make multiple HTTP requests to retrieve contents from the same server. This is known as connection reuse.

During the handshake, the server shares a set of session information with the client. This includes the time the connection will be alive and SSL information containing the encryption keys. If the session ends, both the three-way handshake and the SSL negotiation need to be reestablished. Session reuse ensures the data streaming for the client is not disturbed so the web content or stream data does not have to be reloaded.

How Does Multipath TCP Work?
Let’s use an example of a smartphone with access to both a 4G connection and Wi-Fi interface. Say, the smartphone uses the 4G network to establish the connection to the server. To establish the connection:

  • The smartphone sends a SYN along with the MP_CAPABLE TCP option enabled (indicates the smartphone supports Multipath TCP)
  • The server responds back with SYN+ACK with MP_CAPABLE, after which the connection is established
  • This connection is established between the server and the Smartphone 4G carrier

Now, if the smartphone needs to send data over the Wi-Fi, then it sends a SYN with MP_JOIN TCP option. This option contains all the information required to authenticate and authorize the device and the Wi-Fi. For this, the server responds with SYN+ACK MP_JOIN and the new communication path is established.

By using the multipath TCP, the original connection established will not be closed, which does not affect the data stream and helps smartphone users have data stream consistent while moving from one wireless network to another.

Drawback #2: Flow Control
TCP controls the rate at which data is transmitted between the client and server. The internet infrastructure design is not the same across all regions, which means the amount of traffic handled at one location will not be the same as other.

Say, there are three Internet infrastructures over which the data can be transmitted from server to the client. We see A and C are completely capable of handling the rate at which the data is sent from the server, whereas B has a capacity issue. B can handle only 20Mbps of data, whereas the server sends at a rate of 30Mbps. This would lead to packet loss which in turn would result in retransmission of the lost packets. Retransmission forces the server to wait further for the acknowledgment, resulting in higher load time of the content on the wire.

TCP slow start was introduced to overcome this drawback.

TCP slow start works based on the windowing technique. This helps TCP control the rate at which data is sent over the network, and to understand the maximum capacity of data that can be sent over the wire.

TCP slow start exponentially increases the rate at which data is transmitted. Below we see the flow of data from the server to the client. Slow start initiates with one packet, on an acknowledgment from the client, it increases transmission rates by 2^n (1, 2, 4, 8 …). If any packet loss is observed over the network Slow Start retransmits only the lost packet, rather than sending all the packets in the window.

Slow start increases the window size exponentially until the maximum window size of the receiver is reached or when there’s packet loss due to congestion. In such scenarios, TCP slow start adjusts to the previous window size for which all the packets were acknowledged.

Using TCP slow start, the congestion over the network can be identified early hence reducing the packet loss and the overall retransmission of the lost packets. It also identifies the network capacity enabling the server to send data at a consistent rate over the network. This improves the TCP time which helps users experience a faster and more reliable data transfer.

Concluding with a real-world scenario on how network latency can affect the overall page load time and end user experience of a website.

In the scatterplot graph shown below, we see a lot of outlier data points for the response time or the time taken to load the base HTML page for a website in China. The base HTML page loaded the fastest with a response time of 1.17 seconds while the slowest response time was at 35 seconds as highlighted in the graph. Latency in loading the base request affects the end-user experience as it delays loading the required content on the page.

Scatterplot graph showing the distribution of data for Response Time

So, what could be causing the issue? Is it a slow server or a high network latency which has resulted in the inconsistent response to incoming requests? Catchpoint TCP and TraceRoute monitor types can help with the root cause analysis.

Catchpoint’s TCP and traceroute monitors can identify the network path chosen between the client and the server. Information about each hop in the network (Latency, IP, ISP, and etc.) can provide valuable insights into the impact of network performance on your overall response times. The TCP tests help monitor the time taken for requested content to be routed to the desired destination.

In the current digital landscape, speed and reliable data delivery are critical to a positive user experience. It’s equally pertinent to monitor the routes taken through the Internet to deliver content. This helps us isolate performance degradations caused by network failures or route inefficiencies.

The post Optimize TCP to Speed Through the Digital Freeway appeared first on Catchpoint's Blog - Web Performance Monitoring.

DXWorldEXPO LLC, the producer of the world's most influential technology conferences and trade shows has announced the conference tracks for CloudEXPO | DXWorldEXPO 2018 New York.

DXWordEXPO New York 2018, colocated with CloudEXPO New York 2018 will be held November 11-13, 2018, in New York City.

Digital Transformation (DX) is a major focus with the introduction of DXWorldEXPO within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term.

A total of 88% of Fortune 500 companies from a generation ago are now out of business. Only 12% still survive. Similar percentages are found throughout enterprises of all sizes.

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DXWordEXPO New York 2018 and Cloud Expo New York 2018 agenda present 222 rockstar faculty members, 200 sessions and 22 keynotes and general sessions in 10 distinct conference tracks.

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  • DevOpsSummit
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  • CloudEXPO - Enterprise Cloud
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DXWorldEXPO | CloudEXPO 2018 New York cover all of these tools, with the most comprehensive program and with 222 rockstar speakers throughout our industry presenting 22 Keynotes and General Sessions, 200 Breakout Sessions along 10 Tracks, as well as our signature Power Panels. Our Expo Floor brings together the world's leading companies throughout the world of Cloud Computing, DevOps, FinTech, Digital Transformation, and all they entail.

As your enterprise creates a vision and strategy that enables you to create your own unique, long-term success, learning about all the technologies involved is essential. Companies today not only form multi-cloud and hybrid cloud architectures, but create them with built-in cognitive capabilities.

Cloud-Native thinking is now the norm in financial services, manufacturing, telco, healthcare, transportation, energy, media, entertainment, retail and other consumer industries, as well as the public sector.

CloudEXPO is the world's most influential technology event where Cloud Computing was coined over a decade ago and where technology buyers and vendors meet to experience and discuss the big picture of Digital Transformation and all of the strategies, tactics, and tools they need to realize their goals.

FinTech Is Now Part of the DXWorldEXPO | CloudEXPO Program!

Financial enterprises in New York City, London, Singapore, and other world financial capitals are embracing a new generation of smart, automated FinTech that eliminates many cumbersome, slow, and expensive intermediate processes from their businesses.

Accordingly, attendees at the upcoming 22nd CloudEXPO | DXWorldEXPO November 11-13, 2018 in New York City will find fresh new content in two new tracks called:

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which will incorporate FinTech and Blockchain, as well as machine learning, artificial intelligence and deep learning in these two distinct tracks.

Register for Full Conference "Gold Pass" ▸ Here (Expo Hall ▸ Here)

Show Prospectus V041818 Here

Speaking Opportunities Here

Sponsorship and Speaking Inquiries: [email protected].

FinTech brings efficiency as well as the ability to deliver new services and a much improved customer experience throughout the global financial services industry. FinTech is a natural fit with cloud computing, as new services are quickly developed, deployed, and scaled on public, private, and hybrid clouds.

More than US$20 billion in venture capital is being invested in FinTech this year. DXWorldEXPOCloudEXPO are pleased to bring you the latest FinTech developments as an integral part of our program.

DXWorldEXPO | CloudEXPO are accepting speaking submissions for this new track, so please visit Cloud Computing Expo for the latest information or contact us at [email protected]

Register for Full Conference "Gold Pass" ▸ Here (Expo Hall ▸ Here)

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Speaking Opportunities Here

Sponsorship and Speaking Inquiries: [email protected].

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Only DXWorldEXPO | CloudEXPO bring together all this in a single location:

Attend DXWorldEXPO | CloudEXPO. Build your own custom experience. Learn about the world's latest technologies and chart your course to Digital Transformation.

22nd International DXWorldEXPO | CloudEXPO, taking place November 11-13, 2018, in New York City, will feature technical sessions from a rock star conference faculty and the leading industry players in the world.

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Speaking Opportunities Here

Sponsorship and Speaking Inquiries: [email protected].

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Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises are using some form of XaaS - software, platform, and infrastructure as a service.

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Every Global 2000 enterprise in the world is now integrating cloud computing in some form into its IT development and operations. Midsize and small businesses are also migrating to the cloud in increasing numbers.

Register for Full Conference "Gold Pass" ▸ Here (Expo Hall ▸ Here)

Show Prospectus V041818 Here

Speaking Opportunities Here

Sponsorship and Speaking Inquiries: [email protected].

Download Slide Deck: ▸ Here

Companies are each developing their unique mix of cloud technologies and services, forming multi-cloud and hybrid cloud architectures and deployments across all major industries. Cloud-driven thinking has become the norm in financial services, manufacturing, telco, healthcare, transportation, energy, media, entertainment, retail and other consumer industries, and the public sector.

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DXWorldEXPO | CloudEXPO are the single show where technology buyers and vendors can meet to experience and discus cloud computing and all that it entails. Sponsors of DXWorldEXPO | CloudEXPO will benefit from unmatched branding, profile building and lead generation opportunities through:

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Speaking Opportunities

The upcoming 22nd International DXWorldEXPO | CloudEXPO November 11-13, 2018 in New York City, NY announces that its Call For Papers for speaking opportunities is now open.

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DXWorldEXPO LLC is a Lighthouse Point, Florida-based trade show company and the creator of DXWorldEXPODigital Transformation Conference & Expo. The company produces and presents CloudEXPO, DevOpsSummitFinTechEXPO Blockchain Event, the world's most influential conferences and trade shows.

More Stories By Mehdi Daoudi

Catchpoint radically transforms the way businesses manage, monitor, and test the performance of online applications. Truly understand and improve user experience with clear visibility into complex, distributed online systems.

Founded in 2008 by four DoubleClick / Google executives with a passion for speed, reliability and overall better online experiences, Catchpoint has now become the most innovative provider of web performance testing and monitoring solutions. We are a team with expertise in designing, building, operating, scaling and monitoring highly transactional Internet services used by thousands of companies and impacting the experience of millions of users. Catchpoint is funded by top-tier venture capital firm, Battery Ventures, which has invested in category leaders such as Akamai, Omniture (Adobe Systems), Optimizely, Tealium, BazaarVoice, Marketo and many more.