[SR-Users] Is ACK required in a re-invite?

[Alex Balashov]

On 08/15/2016 06:33 PM, Jay Li wrote:

> Thanks for the quick response. I don't have much experience with SIP.
> I just wonder if you've seen PSTN providers not send an ACK back to
> a re-invite? With your professional experience, is this common?
> Thanks.

Certainly, not sending end-to-end ACKs for 2xx responses is a problem 
that occurs, both for initial and in-dialog invites (reinvites).

However, it indicates that something is misconfigured or improperly 
implemented somewhere, and is a serious issue that needs to be addressed.

-- 
Alex Balashov | Principal | Evariste Systems LLC
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