Cisco Cisco TelePresence MCU 4510 Developer's Guide
HTTP keep-alives
Note: This feature is available from API version 2.4 onwards.
Your application can use use HTTP keep-alives to reduce the amount of TCP traffic that results from
constantly polling the device. Any client which supports HTTP keep-alives may include the following line in
the HTTP header of an API request:
constantly polling the device. Any client which supports HTTP keep-alives may include the following line in
the HTTP header of an API request:
Connection: Keep-Alive
This indicates to the device that the client supports HTTP keep-alives. The device may then choose to
maintain the TCP connection after it has responded. If the device will close the connection it returns the
following HTTP header in its response:
maintain the TCP connection after it has responded. If the device will close the connection it returns the
following HTTP header in its response:
Connection: close
If this line is not in the HTTP header of the response, the client may use the same connection for a
subsequent request.
subsequent request.
The device will not keep a connection alive if:
n
the current connection has already serviced the allowed number of requests
n
the current connection has already been open for the allowed amount of time
n
the number of open connections exceeds the allowed number if this connection is maintained
These restrictions are in place to limit the resources associated with open connections. If a connection is
terminated for either of the first two reasons, the client will probably find that the connection is maintained
after the next request.
terminated for either of the first two reasons, the client will probably find that the connection is maintained
after the next request.
Note: The client should never assume a connection will be maintained. Also, the device will close an open
connection if the client does not make any further requests within a minute. There is little benefit to keeping
unused connections open for such long periods.
connection if the client does not make any further requests within a minute. There is little benefit to keeping
unused connections open for such long periods.
Cisco TelePresence MCU API 2.10
Page 187 of 296
Related information
HTTP keep-alives