Latency. FaceTime on WiFi/LTE.

“I think to myself, what a wonderful world!”

Everyday there is something new to learn!

Learn a lot form two CDN veterans this morning:
1.DNS-based global server load balancing will response to the nameserver of the resolver, the resolver’s nameserver will then query again the hostname in the the respond. If the hostname is pointing to a CDN host, then the CDN nameserver will response to the resolver’s nameserver. These two DNS resolutions are independent of each other and they can use different logics/mechanisms.

Some high-traffic websites use “intelligent” DNS-based GSLB to implement multi-CDN strategy to further improve site performance and ROI. Latency caused by an additional round of CNAME resolution is a good trade-off.

2.Jakob Nielsen, in 1993, published the “3 important limits” of response time:
-0.1 second is the limit for having the user to feel the system in reacting
-1.0 second is the limit for having the user to stay uninterrupted
-10 seconds is the limit for having the user to keep attention
http://www.useit.com/papers/responsetime.html

3.Fiona Nah’s study in 2004 found tolerable wait time (TWT) of web user was 4 second. People are losing patience and unwilling to wait.
http://www.webgiftgr.com/eblog/webgift-blog-news/psychology-web-performance.html

4.Google experienced 20% drop in traffic (and revenue) if there was a 500ms load time increase. Amazon found a 1% drop in sales resulted from a 100ms page load time delay.
http://managewp.com/page-load-speed

5.80% of response time is front-end related for landline users and 97% for mobile users! We have more latencies in 3G than xDSL/FTTB.
http://www.webperformancetoday.com/2011/04/20/desktop-vs-mobile-web-page-load-speed/

6.In the last decade there were many technology development and upgrades in datacenter and last mile. To leverage these investments, telcos should provide CDN services.

 

I did some simple tests to compare my 3G (MBA to 4S to 3G) and FTTB (MBA to AE to FTTB) services:

96ms vs 5ms…

What cause the latency in 3G? Network equipment, air interface and user equipment. From a 2009 Nokia Siemens whitepaper, we have the following “expected” roundtrip latencies:
HSPA: 41ms
HSPA+: <25ms
LTE: <20ms

Video conferencing connects people at different locations. That’s why biz people use telepresence, WebEx, Skype… Responsiveness is the major quality factor in video conferencing. When LTE becomes the most common cellular (it is a more politically correct term, thanks Apple!) technology, then we will have true mobile communication!

FaceTime on LTE (&HSPA+). One More Thing for iPhone 5?

What a wonderful world, Louis Armstrong, youtube

Advertisements

5 Comments on “Latency. FaceTime on WiFi/LTE.”

  1. Hi, I do think your web site could possibly be having browser compatibility problems.

    When I look at your blog in Safari, it looks fine however,
    if opening in Internet Explorer, it’s got some overlapping issues. I simply wanted to provide you with a quick heads up! Other than that, great blog!

    • Andre says:

      Are you talking about my blog andrecheung.wordpress.com or my demo site demo.cheungwaikin.com? My demo site is optimized for iPhone/iPad and it may looks not great on PC. I am using Mac and have not yet use PC to check browser compatibility of my blog.

      Thank you very much for your advise and support. It is glad you find my blog interesting. My blog does not have any design… my future goal is to make it looks great like yours:)

  2. Hello, after reading this remarkable post i am too cheerful to share my experience here
    with mates.

  3. I like the helpful information you provide to your
    articles. I’ll bookmark your blog and check again right here frequently. I am quite sure I will be told many new stuff right here! Good luck for the next!


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s