4

Will all requests processing over HTTP/1.1 if part of content supports HTTP/2? For example, My web server supports only HTTP/1.1, I've made integration with CDN that supports HTTP/2 by default. When I will open a page from my site first request/response will be over HTTP/1.1, but next requests could be processed over HTTP/2 because those requests will go to CDN.

Sergey Vaskov
  • 43
  • 1
  • 3
  • I'm not sure I understand your setup. Normally the CDN should be acting as a proxy and users should not connect to the actual server, only to the CDN proxies. Could you provide some more detail? (Anyhow, I don't think there will be a problem, browsers negotiate the protocol per connection) – Schwern Feb 01 '17 at 07:23
  • @Schwern About setup - Yes, the CDN works as a proxy, but usually for static content, site's pages loading from the customer's servers. Therefore we could get some index page from one server and content placed on this page from another server. About negotiation - yea, I know it, but I wasn't sure and asked :) It's not a common situation and docs didn't explain the situations like this. – Sergey Vaskov Feb 01 '17 at 08:00

2 Answers2

4

You will have no problems, because browsers support both HTTP/1.1 towards your site and HTTP/2 towards the CDN.

Browsers can speak different protocols to different domains, and are able to "merge" the content they receive from those different domains into a single page.

See also: What happens when a browser that supports SPDY receives an HTTP2 (H2) response?.

Community
  • 1
  • 1
sbordet
  • 16,856
  • 1
  • 50
  • 45
  • Thank you for the answer! :) – Sergey Vaskov Feb 01 '17 at 10:30
  • do you know if the content downloaded from the CDN takes advantage of the parallel download p er channels or does it attempt to download the assets using the 6 parallel connection strategy used by most http/1.1 browsers? – Bob9630 Apr 07 '18 at 00:41
  • If the download from the CDN uses HTTP/2, it will benefit of the multiplexing feature of HTTP/2, and so it will _not_ be limited to 6 parallel downloads. – sbordet Apr 07 '18 at 08:12
2

HTTP2:

  • Is extending, not replacing, the previous HTTP 1.1 standards
  • It just modifies how the data is formatted (framed) and transported between the client and server
  • Does not modify the previous application semantics in any way. existing applications can be delivered without modification. (HTTP methods, status codes, URIs, and header fields, remain in place)

So you will be ok. By the way in Chrome > Network > "Protocol column" you can see the protocol used in the transaction.

enter image description here

Juanma Menendez
  • 17,253
  • 7
  • 59
  • 56