Subject: Re: [MOBILE-IP] 3G RAN and IP mobility

From: "G. Ensuque" <[email-masked]>
Date: Fri, 27 Aug 1999 10:53:24 +0100

Andrew

OK, OK ... I am maybe a bit young and naive. Sorry for all the fuss...
But please, don't let the irony overshadow the main point:

I don't want the company I am working for to buy loads of ATM switches just
because an old-fashioned idea from researchers that have now changed their
focus has been adopted in the 3GPP standards, and then find out that there
is a better, cheaper, more efficient solution that is available in the same
timeframe.

Clearly, what would be great to work towards is a protocol that can replace
AAL2 switching in the RAN and integrates well with the rest of the Internet.
Cellular IP or HAWAI are major steps in that direction.

What is important is the performance issue, so could we discuss the
following requirements:

1.      The transport protocol must provide on-demand connectivity from any
RNC (~BSC) to arbitrary 'neighbour' Node Bs (~BTS) or RNCs.
2.      During handover, connectivity between the S-RNC (the RNC that does
the frame selection) and new members of an MT's active set must be
established within the delay bounds implied by the subscribed-to end-to-end
QoS (in the case of voice service, this may require association setup times
of less than e.g. 100ms).
3.      The transport protocol must provide tight synchronisation of L1 bit
frames transmitted on diversity sub-paths from the splitting point in the
downlink direction, so that radio Tx is synchronised between the Node Bs in
the active set (this may require to determine and guarantee an appropriate
delay/jitter behaviour on the diversity sub-paths). Uplink transport of bit
frames from the Node Bs to the combining point may not require such a tight
synchronisation, depending on the subscribed-to QoS for the upper layer
end-to-end service.
4.      The transport protocol must be able to meet the aggregate QoS
requirements of all MS's connected to the UTRAN.

> -----Original Message-----
> From: Andrew T. Campbell [SMTP:[email-masked]]
> Sent: 27 August 1999 13:48
> To:   [email-masked]
> Cc:   [email-masked];
> [email-masked]
> Subject:      Re: [MOBILE-IP] 3G RAN and IP mobility
>
>
> I once worked on ATM, before that x.25, before that I
> built sand castles on the beach an Blackpool. So what!
> http://comet.columbia.edu/~campbell

---

From: "Casati, Alessio (Alessio)" <[email-masked]>
Date: Fri, 27 Aug 1999 11:37:22 +0100

I think that a protocol that satisfies the requirements is
right AAL2 :)

For instance, that radio frames must be transported on links between the
RNC/SDU and the RF gear and IP on its own, without AAL2 equivalent
multiplexing functionality built on top of that, can't do much.

Anyway, this discussion is not particularly fitting in the Mobile IP
list context :).

Since access networks are (have been) defined elsewhere, here we have
to define how to support mobility among them. It's the case that for now
(and for good) we are likely not to need smarter things than
a previous FA extension to make MIP perform well.

In the future there will be certainly time to discuss about
other aspects that we don't have to cope with now.

alessio