Page Download Time Breakdown graph breakdown options

The Page Download Time Breakdown graph breaks down each component by DNS resolution time, connection time, time to first buffer, SSL handshaking time, receive time, FTP authentication time, client time, and error time.

These breakdowns are described below:

Name Description

DNS Resolution

Displays the amount of time needed to resolve the DNS name to an IP address, using the closest DNS server. The DNS Lookup measurement is a good indicator of problems in DNS resolution, or problems with the DNS server.

Connection

Displays the amount of time needed to establish an initial connection with the web server hosting the specified URL. The connection measurement is a good indicator of problems along the network. It also indicates whether the server is responsive to requests.

First Buffer

Displays the amount of time that passes from the initial HTTP request (usually GET) until the first buffer is successfully received back from the web server. The first buffer measurement is a good indicator of web server delay as well as network latency.

Note: Since the buffer size may be up to 8K, the first buffer might also be the time it takes to completely download the element.

SSL Handshaking

Displays the amount of time taken to establish an SSL connection (includes the client hello, server hello, client public key transfer, server certificate transfer, and other—partially optional—stages). After this point, all the communication between the client and server is encrypted.

The SSL Handshaking measurement is only applicable for HTTPS communications.

Receive

Displays the amount of time that passes until the last byte arrives from the server and the downloading is complete.

The Receive measurement is a good indicator of network quality (look at the time/size ratio to calculate receive rate).

FTP Authentication

Displays the time taken to authenticate the client. With FTP, a server must authenticate a client before it starts processing the client's commands.

The FTP Authentication measurement is only applicable for FTP protocol communications.

Client Time

Displays the average amount of time that passes while a request is delayed on the client machine due to browser think time or other client-related delays.

Error Time

Displays the average amount of time that passes from the moment an HTTP request is sent until the moment an error message (HTTP errors only) is returned.

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