Low-Level Features of the Internet

Find out how long it takes to "ping" the google.com server:

In[1]:=

PingTime["google.com",20]

Out[1]=

{

32.654

20.932

19.726

10.546

9.956

24.983

21.365

36.147

29.7

9.427

8.539

9.964

19.52

19.957

12.509

18.686

18.732

20.246

10.804

16.74

}

Now try it for the Chinese site baidu.cn:

In[2]:=

PingTime["baidu.cn",20]

Out[2]=

{

236.716

243.129

233.692

232.796

236.375

233.295

232.114

264.368

237.222

236.817

251.83

278.436

236.59

242.432

245.903

235.127

235.661

250.695

241.528

238.32

}

Make a histogram of ping times:

In[3]:=

Histogram[PingTime["baidu.cn",50]]

Out[3]=

Get the distance from here to Beijing, divided by the speed of light:

In[4]:=

GeoDistanceHere,

Beijing

CITY



Out[4]=

6599.89

mi/

Convert to standard units:

In[5]:=

UnitConvert[%]

Out[5]=

0.0354295

The result is 35 ms (35 milliseconds), which is only 10% of the actual ping time to baidu. (Signals in optical fibers go 50% slower than the speed of light in a vacuum, but the transmission time is not the main effect; it's mostly time spent in relays and repeaters.)

Look up the IP addresses for baidu.cn:

In[6]:=

HostLookup["baidu.cn"]

Out[6]=

{IPAddress[220.181.38.148],IPAddress[220.181.38.251],IPAddress[39.156.66.10]}

Note that some sites don't allow pinging:

In[7]:=

PingTime["hku.hk"]

PingTime

:No ping echo received from host hku.hk within the specified timeout.

Out[7]=

Failure



Message:

No ping echo received from host

hku.hk

within the specified timeout.

Tag:

Timeout



Low-Level Interactions
(3)

Read from a URL:

In[1]:=

URLRead["https://www.google.com"]

Out[1]=

HTTPResponse

Status: OK

Content type: text/html; charset=ISO-8859-1



Here's the first 20 lines of the actual body that's returned:

In[2]:=

Snippet[%["Body"],20]

Out[2]=

<!doctype html><html itemscope="" itemtype="http://schema.org/WebPage"lang="en"><head><meta content="Search the world's information, includingwebpages, images, videos and more. Google has many special features to help youfind exactly what you're looking for." name="description"><meta content="noodp"name="robots"><meta content="text/html; charset=UTF-8"http-equiv="Content-Type"><metacontent="/images/branding/googleg/1x/googleg_standard_color_128dp.png"itemprop="image"><title>Google</title><scriptnonce="X_fb5cDET5QZmCbcD6xC9w">(function(){var_g={kEI:'lypmZdHCOfOdptQP-sK5qAg',kEXPI:'0,1365468,206,4804,2316,383,1129371,1920,1195806,380764,16115,28684,22430,1362,12317,4747,12835,4998,17075,39333,1983,2891,3926,213,7615,606,29843,46171,781,1244,1,16916,2652,4,32894,26723,2980,1457,22616,6624,7593,1,42154,2,16395,342,23024,6700,951,30170,4569,6258,17110,6308,1249,33067,2,2,1,10956,15676,8155,23351,873,19632,8,1922,9779,38677,3782,20198,20137,14,82,2932,13582,3692,109,2412,24816,5403,3030,15816,1804,7734,15103,2995,575,8862,11813,1635,8839,14023,499,11252,21746,5209428,44,667,2,296,284,134,48,530,5993673,2803219,3306,141,795,30198,116,2,2,2,2,2,44,9,1,5,5,3,23940177,4044106,16673,43886,3,1599,3,503,3,1393942,338513,388821,23031936,7950,1,212,4636,8408,2879,335,1260,3554,6509,163,19415,5456,5121,5878,14281,325,8776,850,873,2,14701,1,1,2,3,1688,1283,769,27,6,5,15,313,446,7,1,8,5021,4,872,439,663,1770,1400,1068,36

Evaluate this to find the cookies being used from your Wolfram Language system:

In[3]:=

$Cookies

Publisher Information

Contributed by: Wolfram Staff

Low-Level Features of the Internet

Low-Level Interactions (3)

Related Symbols

Publisher Information

Low-Level Interactions
(3)