You can use the BIG-IP® Local Traffic Manager™ SPDY (pronounced "speedy") profile to minimize latency of HTTP requests by multiplexing streams and compressing headers. When you assign a SPDY profile to an HTTP virtual server, the HTTP virtual server informs clients that a SPDY virtual server is available to respond to SPDY requests.
When a client sends an HTTP request, the HTTP virtual server, with an assigned iRule, manages the request as a standard HTTP request. It receives the request on port 80, and sends the request to the appropriate server. When the BIG-IP provides the request to the origin web server, the virtual server's assigned iRule inserts an HTTP header into the request (to inform the client that a SPDY virtual server is available to handle SPDY requests), compresses and caches it, and sends the response to the client.
A client that is enabled to use the SPDY protocol sends a SPDY request to the BIG-IP system, the SPDY virtual server receives the request on port 443, converts the SPDY request into an HTTP request, and sends the request to the appropriate server. When the server provides a response, the BIG-IP system converts the HTTP response into a SPDY response, compresses and caches it, and sends the response to the client.
By using the SPDY profile, the BIG-IP Local Traffic Manager system provides the following functionality for SPDY requests.
This table provides descriptions of the SPDY profile settings.
|Name||Type the name of the SPDY profile.|
|Parent Profile||spdy||Specifies the profile that you want to use as the parent profile. Your new profile inherits all settings and values from the parent profile specified.|
|Concurrent Streams Per Connection||10||Specifies how many concurrent requests are allowed to be outstanding on a single SPDY connection.|
|Connection Idle Timeout||300||Specifies how many seconds a SPDY connection is left open idly before it is closed.|
|Activation Mode||NPN||Specifies how a connection is established as a SPDY connection. The value NPN specifies that the Transport Layer Security (TLS) Next Protocol Negotiation (NPN) extension determines whether the SPDY protocol is used. Clients that use TLS, but only support HTTP will work as if SPDY is not present. The value Always specifies that all connections must be SPDY connections, and that clients only supporting HTTP are not able to send requests. Selecting Always in the Activation Mode list is primarily intended for troubleshooting.|
|Insert Header||Disabled||Specifies whether an HTTP header that indicates the use of SPDY is inserted into the request sent to the origin web server.|
|Insert Header Name||X-SPDY||Specifies the name of the HTTP header controlled by the Insert Header Name setting.|
|Protocol Versions||All Versions Enabled||Used only with an Activation Mode selection of NPN, specifies the protocol and protocol version (http1.1, spdy2, spdy3, or All Version Enabled) used in the SPDY profile. The order of the protocols in the Selected Versions Enabled list ranges from most preferred (first) to least preferred (last). Adding http1.1 to the Enabled list allows HTTP1.1 traffic to pass. If http1.1 is not added to the Enabled list, clients that do not support http1.1 are blocked. Clients typically use the first supported protocol. At least one SPDY version must be included in the Enabled list.|
|Priority Handling||Strict||Specifies how the SPDY profile handles priorities of concurrent streams within the same connection. Selecting Strict processes higher priority streams to completion before processing lower priority streams. Selecting Fair enables higher priority streams to use more bandwith than lower priority streams, without completely blocking the lower priority streams.|
|Receive Window||32||Specifies the receive window, which is SPDY protocol functionality that controls flow, in KB. The receive window allows the SPDY protocol to stall individual upload streams when needed. This functionality is only available in SPDY3.|
|Frame Size||2048||Specifies the size of the data frames, in bytes, that the SPDY protocol sends to the client. Larger frame sizes improve network utilization, but can affect concurrency.|
|Write Size||16384||Specifies the total size of combined data frames, in bytes, that the SPDY protocol sends in a single write function. This setting controls the size of the TLS records when the SPDY protocol is used over Secure Sockets Layer (SSL). A large write size causes the SPDY protocol to buffer more data and improves network utilization.|