[SIPForum-discussion] Retry mechansim

[Dale R. Worley]

sipsipsip sip <sipsipsip.123 at gmail.com> writes:
> Can anyone share me the retry behaviors for Registration and Invite request
> .
>
> Especially for 4XX & 5XX , since we dont have any specific specification
> for these request .

There aren't specifications.

Usually, when an INVITE fails, that is reported to the user as the call
failing.

With REGISTER, a common strategy is to periodically attempt to
re-REGISTER, say at intervals of slightly less than 1/3 of the
registration time that was granted with the last registration.  (IIRC,
that behavior is copied from DHCP behavior for renewing IP addresses.)
That means that the device has 3 attempts to renew its registration, and
they are widely spaced in time, which minimizes the chances that network
problems will prevent re-registration.

A number of phones that I have used have a user interface feature
whereby the user can order the phone to re-register.

Dale