From H.245 tunneling to separate connection?

Chris Wayman Purvis cwp at ISDN-COMMS.CO.UK
Tue Aug 17 09:13:03 EDT 1999

More realistically:
Call transfer scenarios can happen where "transfer" functionality is provided
by a routing gatekeeper, meaning that the transferred endpoint A (the one
involved in both a pre-transfer call to B and a post-transfer call to C) does
not notice any change in terms of a new call coming up (this is permitted by
H.450.2 in circumstances where A does not speak H.450).  It will however see
(and take part in) fresh H.245 negotiations.
Now suppose A and B both support tunnelling and C doesn't, so the initial call
from A to be used tunnelling.  Post-transfer, either the call needs to switch
over to non-tunnelled H.245, or the gatekeeper gains a whole load of extra work
it really didn't want.


Pekka Pessi wrote:
> Paul Long <Plong at SMITHMICRO.COM> writes:
> >Why would an EP ever want to switch from H.245 tunneling to a separate H.245
> >connection? What possible use could there be in such a thing?
>         The H.245 might be handled by a different box than the Q.931?  I
>         think Paul Sijben from Lucent presented a scenario, where Q.931 was
>         handled by a MGC and H.245 by MG.  (He also presented quite many
>         reasons why nobody would really implement such a scenario.)  Another
>         possibility would be a distributed MC, where the Q.931 is handled by
>         one box and H.245 by other ones.
>                                         Pekka Pessi

Dr Chris Purvis -- Development Manager
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