| The Record-Route header field is inserted by proxies in a request to force
future requests in the dialog to be routed through the proxy. The
SipProvider (as opposed to the application) should attach Record-Route
headers to messages explicitly when forwarding them if necessary.
The RecordRouteHeader is added to a Request by any proxy that insists on being
in the path of subsequent Requests for the same call leg. It contains
a globally reachable RequestURI that identifies the proxy server. Each proxy
server adds its Address URI to the beginning of the list.
The calling user agent client copies the RecordRouteHeaders into
RouteHeaders of subsequent Requests within the same call leg, reversing the
order, so that the first entry is closest to the user agent client. If the
Response contained a ContactHeader field, the calling user agent adds its
content as the last RouteHeader. Unless this would cause a loop, a client
must send subsequent Requests for this call leg to the Address URI in the
first RouteHeader and remove that entry.
Some proxies, such as those controlling firewalls or in an automatic call
distribution (ACD) system, need to maintain call state and thus need to
receive any BYE and ACK Requests for the call.
For Example:
Record-Route: sip:server10.jcp.org;lr,
sip:bigbox3.duke.jcp.org;lr
See Also: RouteHeader
See Also: HeaderAddress
See Also: Parameters
author:
BEA Systems, NIST
version:
1.2 |