CODEWITHSUNDEEP
performancehttpbrowser
calicode
calicode

Reputation: 237

Do modern browsers still limit parallel downloads?

In this Yahoo article from 2007, the authors argue that static assets should be split across different hostnames because browsers follow a suggestion from the HTTP/1.1 spec to limit parallel downloads to two per hostname.

My question is, do modern browsers still follow this limit? Using firebug, I noticed that my browser is downloading many more than 2 files in parallel.

Upvotes: 18

Views: 5621

Answers (3)

Michael Eliot
Michael Eliot

Reputation: 1196

For anyone wandering into this nearly 13 years later, this is a restriction in http/1, but isn't in http/2 and http/3. You can read a good article why here, and a discussion on the differences here.

The TL;DR is that http/1 worked by creating separate TCP connections for separate requests. This could easily flood a webserver with tcp connections, and thus was capped. http/2 and http/3 don't work this way, and thus don't need the restriction.

http/2 and http/3 do allow for limits by the server (not the browser), but it's usually very high (100s).

Upvotes: 0

sra
sra

Reputation: 23983

Microsoft till IE 7 is limited to two IE 8 and 9 to six. Firefox is limited to six. There is a fix out from ms to modify all to ten: http://support.microsoft.com/kb/282402

you can asume that all modern browsers have a default limit of six

Update

Here's a good source for comparing actual browser and their MaxConnextions

Upvotes: 18

a3nm
a3nm

Reputation: 8884

Yes, there is still a limit. With Firefox, you can go to about:config and look at the value of network.http.max-connections and network.http.max-connections-per-server.

Upvotes: 6

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