2019-09-21
Suppose you click on a page while browsing a hyperlink, URL for the "https://www.kicker.com.cn/index.html", and the URL corresponding IP address is not cached on your computer; file index .html cited 8 small images. Domain name resolution process, without waiting for a time of DNS resolution request and response denoted RTTd, HTTP requests the first round trip time transmission process referred to as Web objects RTTh. please answer the following question:
1) Your browser URL resolves to the IP address corresponding to the minimum time is how much? The maximum time is how much?
2) If the browser is not configured in parallel TCP connections, based on HTTP1.0 get the full URL link to a Web page content (including a reference image, the same below) How long (not including time domain analysis, the same below)?
3) If the browser is configured to 5 concurrent TCP connections, based on HTTP1.0 obtain the URL link to the full contents of the Web page How long?
4) If the browser is not configured in parallel TCP connections, to obtain the complete URL link to a Web page based on a non-flow mode HTTP1.1 how long it takes? How long HTTP1.1 flow model to obtain the URL link to the full contents of a Web page based on?
my answer
answer:
1) browser URL resolves to the IP address corresponding to the minimum time is:
In the case of the host no cache, the local cache DNS server IP address of the domain name, the shortest time is RTTD .
Maximum time is:
Hosts is not cached in the case and use a recursive query, the local local DNS server will request to the DNS Root DNS server,
Then Root DNS server DNS server request to the top-level domain TLD, then the top-level domain TLD DNS server request to the authoritative name servers,
After the authoritative name servers to find the IP address of the DNS request is a request to return to the original road layer by layer, the maximum time for the (+. 1. 4). 5 = * RTTD RTTD .
2) If the browser is not arranged parallel TCP connection, HTTP1.0 is based on (a non-persistent connection, a TCP connection allows the transmission of up to one object, a total of 1 + 8 html content image, a total of nine open tcp connection, it more than nine times the RTT time.)
Get the URL link to a Web page full content How long (not including time domain analysis) as follows:
2 * (a TCP connection establishment time + (a small image transfer time html content transmission times of the time required +8))
= 2*（RTTh+RTTh+8*RTTh） = 18*RTTh。
3) If the browser is configured to five concurrent TCP connections, HTTP1.0 is based on (a non-persistent connection, each TCP connection allows the transmission of up to one object)
Get the URL link to the complete contents of Web pages required time:
(RTTh + establish a TCP connection to obtain the contents of the html file RTTh) + 2 * wheel 8 images acquired address information RTTH = 2RTTh + 2 * 2 = th rTth 6RTTh .
4）
If the browser is not configured in parallel TCP connections, to obtain the complete URL link to a Web page based on HTTP1.1 non-flow mode requires time:
1RTTh (TCP persistent connections) + 1RTTh (1 Ci html content acquisition) + 8RTTh (8 image transfer time) = 10RTTh .
HTTP1.1 flow model to obtain the complete URL link to a Web page based on the time required to:
1RTTh (TCP persistent connections) + 1RTTh (1 Ci html content acquisition) + 1RTTh (8 image transfer time) = 3RTTh .
Answer: No