details are not provided for features introduced before release 21.2.
During LTE to WiFi
handover, if Create Bearer Request reaches ePDG before Create Session Response,
then it is dropped, as dedicated bearer is created only after session
establishment is done. In this scenario, PGW will try to Create Bearer Request
after 3 seconds, which in turn delays bearer creation.
resolves this issue by sending Create Session Response and Create Bearer
Request in one message from PGW so that ePDG can process sequentially. This
feature is nonstandard feature (non-3GPP). S2b Piggybacking support is
controlled by CLI present under call-control-profile, this is disabled by
Supported flag will be set for both initial attach and handoff sessions.
Bearer Request and Create Session Response messages will be supported as
piggybacked during session creation.
Configuring ePDG S2b
Use the below configuration to
configure Piggybacking Support. A new key word
wlan piggybacking is introduced to support this feature.