How to achieve low latency with 10Gbps Ethernet

Good morning!

In a recent blog post we explained how to tweak a simple UDP application to maximize throughput. This time we are going to optimize our UDP application for latency. Fighting with latency is a great excuse to discuss modern features of multiqueue NICs. Some of the techniques covered here are also discussed in the scaling.txt kernel document.

CC BY-SA 2.0 image by Xiaojun Deng

Our experiment will be setup up as follows:

  • We will have two physical Linux hosts: the 'client' and the 'server'. They communicate with a simple UDP echo protocol.
  • Client sends a small UDP frame (32 bytes of payload) and waits for the reply, measuring the round trip time (RTT). Server echoes back the packets immediately after they are received.
  • Both hosts have 2GHz Xeon CPU's, with two sockets of 6 cores and Hyper Threading (HT) enabled - so 24 CPUs per host.
  • The client has a Solarflare 10Gb NIC, the server has an Intel 82599 10Gb NIC. Both cards have fiber connected to a 10Gb switch.
  • We're going to measure the round trip time. Since the numbers are pretty small, there is a lot of jitter when counting the averages. Instead, it Continue reading

Reading

"

Reading takes a long time, though, don’t you find? It takes such a long time to get from, say, page twenty-one to page thirty. I mean, first you’ve got page twenty-three, then page twenty-five, then page twenty-seven, then page twenty-nine, not to mention the even numbers. Then page thirty. Then you’ve got page thirty-one and page thirty-three — there’s no end to it. Luckily Animal Farm isn’t that long a novel. But novels . . . they’re all long, aren’t they. I mean, they’re all so long.

" Martin Amis, Money —

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The Upload: Your tech news briefing for Tuesday, June 30

Government personnel agency takes background check system offline for background checksHoping to avoid a third strike against it, the U.S. Office of Personnel Management has taken offline a system used for performing background checks on potential new hires. The agency discovered a security flaw in the web app, E-QIP, while auditing its IT systems after two spectacular hacks resulted in the theft of personnel records of millions of government employees and the security clearance questionnaires of many others. There is no evidence the flaw was exploited, OPM said Monday, but it will keep the system offline for up to six weeks while it checks it out.To read this article in full or to leave a comment, please click here

Push It To The Limit! Understand Wi-Fi’s Breaking Point to Design Better WLANs

This is the fourth and final blog post in the WLAN capacity planning series. Be sure to read the first, second, and third posts.

We all want high performing WLANs. In order to do that we must push Wi-Fi to its limits! 

(Cue Scarface Theme, verse 1)…

“Push it to the limit!
Walk along the perimeter edge
But don’t look up, just keep your head
And you’ll be finished

Survey to the limit!
Past the point of no bandwidth
You’ve reached the edge but still you gotta learn
How to build it

Hit the floor and double your pace
Laptop wide open like an engineer outta hell
And you crush the speed test

Going for the back of every room
Nothing gonna stop you
There’s no wall that strong
So close now, battery near the brink
So, push it!”

We walk a fine line when designing wireless networks, attempting to push as many users and bandwidth through our APs as possible, ensuring adequate capacity is available to meet demand, while not overbuilding the network. But what are the limits and how do we know we’ve hit them? Or more importantly, how do we plan Continue reading

Gartner lowers its IT spending forecast, but says activity remains high

Worldwide IT spending is expected to decline by 5.5 percent this year, with enterprises benefitting from lower prices on communications and IT services but also having to pay higher hardware prices in some parts of the world.Market research company Gartner revised its spending forecast downward on Tuesday: In April, it said IT spending in 2015 would decline 1.3 percent compared to last year.But numbers can sometimes be deceptive; IT activity is stronger than the spending indicates, according to John-David Lovelock, research vice president at Gartner. Price declines in segments like communications and IT services, and the move to cloud-based services, mask an increase in activity, he said.To read this article in full or to leave a comment, please click here

Junos Space backup location

Just a note for future reference:

Space’s local database backups are kept in /var/cache/jboss/backups  (Platform version 13.1R1)

You can retrieve these using WinSCP in SFTP mode.   For some reason there’s a shell error when using SCP. This appears to have started happening since the bash shell vuln was discovered – although I’ve never applied Juniper’s bash patch to the system.   Upgraded WinSCP to the latest, but no luck.


Junos Space backup location

Just a note for future reference:

Space’s local database backups are kept in /var/cache/jboss/backups  (Platform version 13.1R1)

You can retrieve these using WinSCP in SFTP mode.   For some reason there’s a shell error when using SCP. This appears to have started happening since the bash shell vuln was discovered – although I’ve never applied Juniper’s bash patch to the system.   Upgraded WinSCP to the latest, but no luck.


Project Calico: Is It Any Good?

At least a dozen engineers sent me emails or tweets mentioning Project Calico in the last few weeks – obviously the project is getting some real traction, so it was high time to look at what it’s all about.

TL&DR: Project Calico is yet another virtual networking implementation that’s a perfect fit for a particular use case, but falters when encountering the morass of edge cases.

Read more ...

OPM hit by class-action suit over breach of federal employee data

A federal employees union has filed a lawsuit against the U.S. Office of Personnel Management, its leadership and a contractor, alleging that their negligence led to a data breach that compromised the personal information of millions of current, former and prospective government employees and contractors.Since at least 2007, the OPM has been warned by its Office of Inspector General of significant deficiencies in its cybersecurity protocol, according to the proposed class-action suit filed Monday by the American Federation of Government Employees in the U.S. District Court for the District of Columbia.However, OPM failed to take measures to correct these issues, despite handling massive amounts of federal applicants’ private, sensitive and confidential information, it added. The data handled by the OPM included a 127-page form, called Standard Form 86, which requires applicants for security clearances to answer questions on their financial histories and investment records, children’s and relatives’ names, foreign trips and contacts with foreign nationals, past residences, and names of neighbors and close friends, according to the filing.To read this article in full or to leave a comment, please click here

Which songs stumped Shakira? Shazam will now show you

Shazam is releasing a new version of its music recognition app that lets users connect with artists they like and see what songs they’ve searched for using its service.Shazam lets people identify songs, TV shows and movies by capturing a brief snippet onto their phone, which gets matched against Shazam’s database. The new version due out Tuesday, for iOS and Android, lets users see what songs have been identified by artists using the app. Because not even musicians know every song that’s playing.To read this article in full or to leave a comment, please click here

FTC settles with developers of sneaky cryptocurrency mining app

The developers of a mobile app called Prized that secretly mined cryptocurrencies on people’s mobile phones have settled with the U.S. Federal Trade Commission after being accused of deceptive trade practices.Equiliv Investments and Ryan Ramminger, both of Ohio, settled for US$50,000, of which $44,800 will be suspended upon payment of $5,200 to New Jersey regulators, the agency said in a news release Monday. The suit was filed in U.S. District Court for the District of New Jersey last Wednesday.To read this article in full or to leave a comment, please click here

US personnel agency takes system offline after hack

Problems for the U.S. Office of Personnel Management aren’t letting up. The government agency said Monday it had suspended a system used for background checks after a security flaw was discovered in the Web-based app.The agency said there’s no evidence the system was hacked. It discovered the vulnerability during an ongoing review of its IT systems, it said, which is being carried out in the wake of at least two serious security breaches.Still, it’s a big inconvenience. The system, called E-QIP, is used by multiple agencies to carry out background checks on potential new hires, and it will be offline for four to six weeks, the OPM said.“The actions OPM has taken are not the direct result of malicious activity on this network, and there is no evidence that the vulnerability in question has been exploited,” the agency said, calling the decision to take E-QIP offline a proactive measure to ensure ‘the ongoing security of its network.”To read this article in full or to leave a comment, please click here

Microsoft hands some of the reins for its display ad business to AOL

Microsoft will be handing over its display advertising business to AOL in nine markets as part of a new partnership between the two companies that was announced Monday.Under the deal, AOL will use Bing to power search through its website, and will operate display advertising, including mobile and video ads, for Microsoft’s portfolio in Brazil, Canada, France, Germany, Italy, Japan, Spain, U.K. and the U.S. That means AOL will be powering all the display ads that run in those countries, including on MSN, Xbox, Outlook.com and Skype.To read this article in full or to leave a comment, please click here

Microsoft parental control update lets kids browse more than they should

A new version of Microsoft’s parental control product is ready for the Windows 10 launch, but users are complaining about a serious bug as well as features they don’t like.The free service, known previously as Family Safety, has been rebranded as Microsoft Family and redesigned. The changes are supposed to help families more easily control their kids’ activities on Windows and Windows Phone devices. However, parents are complaining on Microsoft’s support forum about a bug that loosens browsing restrictions.The bug affects accounts that should have their browsing limited to a handpicked “whitelist” of websites. Instead, children can browse beyond the walled garden their parents set up. Unsurprisingly, parents are upset, and they can’t return to the previous version.To read this article in full or to leave a comment, please click here

Uber grabs mapping tech, employees from Microsoft

Uber is adding to its mapping smarts by acquiring technology used by Microsoft’s Bing Maps, and has hired roughly 100 Microsoft employees who work on image collection and data analysis.Microsoft decided it will no longer collect the imagery and data for Bing Maps itself, and will instead rely on partners. Bing Maps will continue to provide driving directions and information about traffic and road conditions.The employees joining Uber constitute “a small number” of Microsoft’s larger maps team, the companies said.For Microsoft, the acquisition fits with its decision a year ago to focus on productivity services, which are at the core of its strategy, a spokeswoman said on Monday.To read this article in full or to leave a comment, please click here

MIT tests ‘software transplants’ to fix buggy code

Like visiting a junk yard to find cheap parts for an aging vehicle, researchers from the Massachusetts Institute of Technology have come up with a way to fix buggy software by inserting working code from another program.Using a system they call CodePhage, the researchers were able to fix flaws in seven common open-source programs by using, in each case, functionality taken from between two and four “donor” programs.Fixing such errors can help make code more secure, since malicious hackers often exploit flaws to gain entry to a system. CodePhage can recognize and fix common programming errors such as out of bounds access, integer overflows, and divide-by-zero errors.To read this article in full or to leave a comment, please click here

Fiber broadband can drive up your home’s value

The availability of really fast broadband in your neighborhood could increase your home’s value by more than 3 percent.High-speed fiber broadband service, with 1 Gbps download speeds, can add more than $5,400 to the value of an average U.S. home, according to a study commissioned by the Fiber to the Home Council Americas (FTTH), an advocacy group made up of fiber equipment vendors and broadband providers.That $5,400 figure is approximately equal to adding a new fireplace, half of a new bathroom or a quarter of a swimming pool, according to the study, conducted by researchers at the University of Colorado at Boulder and Carnegie Mellon University.To read this article in full or to leave a comment, please click here

PayPal tweaks terms in wake of ‘robocall’ controversy

PayPal is fine-tuning its policies after a recently announced plan to make unsolicited prerecorded calls and texts to users drew questions and concerns from customers, regulators and consumer advocates.Earlier this month, PayPal generated controversy when it proposed amendments to its terms that would allow it make unsolicited calls for marketing and other purposes. The Federal Communications Commission told PayPal that the proposed terms, which would go into effect July 1, might violate federal laws because unsolicited robocalls are only legal if a company has obtained written or oral consent from consumers.To read this article in full or to leave a comment, please click here

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