Technical data

Brocade ServerIron ADX Advanced Server Load Balancing Guide 87

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Content-aware cache switching

Bypassing embedded protocols

In network environments where non-HTTP protocols such as FTP and RTSP are masquerading over

port HTTP, ServerIron ADX enables network administrators to bypass such embedded traffic to the

Internet rather than forwarding it to cache servers.

Once this feature is enabled, the ServerIron ADX categorizes port 80 traffic as either true HTTP

traffic or non-HTTP traffic:

• If the traffic is identified as HTTP traffic, then subsequent packets are processed normally

using transparent cache switching (TCS).

• If the traffic is identified as non-HTTP traffic masquerading over port 80, then subsequent

packets are bypassed to the Internet.

Use the bypass-embedded-protocols CLI command, to enable the ServerIron ADX to classify

incoming traffic as either HTTP or non-HTTP traffic. Once enabled, the embedded protocol traffic is

bypassed to the Internet server instead of to the cache servers.

Enter a command such as the following under the ServerIron ADX cache group configuration level:

ServerIronADX(config-tc-1)#bypass-embedded-protocols

Syntax: [no] bypass-embedded-protocols

The no option disables the bypass embedded protocols feature. There are no other operands for

this command.

HTTP 1.1 support for cache switching

Beginning with release 12.4.00, HTTP keep-alive mode is enabled by default for content-aware

cache switching. This has been added to fully support HTTP 1.1 for TCS CSW. Unlike the operation

in previous releases of ServerIron ADX, the client request is not downgraded to HTTP 1.0 and the

connection header is unmodified. The client will send subsequent requests over the same TCP

connection if the server supports HTTP keep-alive. The ServerIron ADX software will maintain the

HTTP state machine to track HTTP request and response transactions. Every HTTP request will be

analyzed and forwarded according to the CSW configuration. When CSW makes a decision to

switch from one server to another server, it will send a TCP reset to the previously chosen server

and establish a TCP connection to the newly selected server

Disabling HTTP keep-alive mode

HTTP keep-alive mode is the default mode for TCS CSW. You can disable keep-alive to return the

ServerIron ADX to HTTP 1.0 mode which was supported in releases prior to 12.4.00, as shown in

the following example.

ServerIronADX(config)#server cache-group 1

ServerIronADX(config-tc-1)#no-keep-alive

Syntax: [no] no-keep-alive

Use the no parameter to re-enable HTTP keep-alive if you have disabled it.