HTTP Connection Management

By default, the ESBC limits system impact caused by HTTP client behavior using the httpclient-max-total-conn and httpclient-max-cpu-load parameters in the system-config. These parameters allow you to change the number of TCP connections and the amount of CPU resources consumed by traffic between the ESBC and all types of HTTP servers.

Use the following system-config parameters to adjust or disable management of the number of active HTTP clients by the ESBC:

• httpclient-max-total-conn—Specifies the maximum number of TCP connections that the http-client allows open simultaneously.

  When this traffic exceeds this value, the ESBC and the http-client begin to discard new http/https requests. When used TCP connections falls below this value, the ESBC resumes accepting HTTP client TCP connections.

  Valid Values:

  • 0—Disables the function
  • Range—0 - 2147483647
  • Default—500

  You cannot configurehttp-client in real time. You must reboot the system whenever you make a change.

• httpclient-cache-size-multiplier—Specifies the multiplier used to calculate the size of the HTTP client connection cache.

  The system maintains an HTTP connection cache pool. This is a collection of previously used connections that the system keeps alive, instead of closing after use, so that subsequent transfers targeting the same host name can use them instead of creating a new connection. The size of the HTTP connection cache is based on the number of these live connections.

  The system calculates this cache size using the formula:

  client connection cache = (number of pending transactions * httpclient-cache-size-multiplier)

  Valid Values:

  • Default: 16
  • Values: 4 - 50

  You cannot configure the http-client in real time. You must reboot the system whenever you make a change.

• http-clearDead-conn-timer—Specifies the number of seconds the system waits before it closes connections to HTTP servers that are in the half closed state.

  The system maintains connections between itself and HTTP servers that is equal to the number of connections in the cache pool multiplied by the httpclient-cache-size-multiplier value when, for example, STIR traffic stops. The system puts these connections in half-closed state after the STIR server tries to close the connections using FIN messages. By default, these connections remain in half closed state indefinitely until STIR traffic starts again. You can set the http-clearDead-conn-timer parameter to a timer value, after which the system clears these connections regardless of STIR traffic status. The value specifies the regular interval the system uses to clear these half-closed STIR server connections.

  Valid Values:

  • Default: 0 (disabled)
  • Values: 300 - 86400

You use the Http/s calls Dropped field in the show sipd errors command to monitor dropped HTTP traffic.