So far, we have discussed the lower layers of the ISO model with SSL, TCP, and Ethernet capabilities. The last piece of this puzzle is the application layer. This is where HTTP/2 and SPDY come in.
Now, HTTP 1.1 is the de facto standard of the Web, it has been around for 11 years and is not optimized for today's Internet.
Over the years, Google has done a lot of work trying to improve this web protocol. The company got as far as creating its own protocol, which was called SPDY. This protocol uses prioritizing and connection multiplexing, which allows the communication flow to go a lot faster. It also has the transmission headers sent using GZIP or deflate, and since the headers are sent in a binary format instead of a readable text like HTTP 1.1 does, it allows for a far better compression ratio.
You can read more about the SPDY protocol at https://www.chromium.org/spdy/spdy-protocol/spdy-protocol-draft3.
On the other hand, we have the HTTP/2 protocol, which has been developed with the IEFT group and is in essence based on the SPDY/4 protocol. This will in the future replace SPDY on Google's platform.
The HTTP/2 protocol has the same characteristics as SPDY, and NetScaler supports both. Most web browsers today already support SPDY and HTTP/2, and the same goes for most web servers.
The way to enable SPDY and HTTP/2 is to create an HTML profile and bind it to a vServer. However, HTTP/2 is not supported on VPX and will therefore fall back to SPDY.
If a client connects to a vServer that has HTTP/2 and SPDY profile enabled, the communication will try in the following order:
- HTTP/2
- SPDY
- HTTP 1.1
The HTTP profiles can be found under System | Profiles | HTTP Profiles.
Here, we can make the change, as shown in the following screenshot, to enable HTTP/2 and SPDY. Choose ENABLED under the SPDY parameter. This will enable SPDY v2 and v3 and allow the client to negotiate between the two, then add the checkmark on HTTP/2, as shown in the following screenshot:
