I've long held the belief that "seamless" is a nonsense term - at best an irrelevance, and at worst a dangerous distraction. I remember Motorola announcing its adoption of the term "seamless mobility" a couple of years ago, at a point when the term was already trite. A pity, because it's generally a quite smart product & technology strategy, masked by stupid marketing guff & a lousy brand.
Up until now, "seamless" has tended to be used mostly by people talking about handing off voice calls from cellular to WiFi networks, using dual-mode phones. It's one of the features of UMA (which was designed around facilitating it) and it is often emulated/hyped/exaggerated about the various SIP and IMS/VCC based alternatives.
The idea is that the end-user should remain blissfully unaware of what the technology is connecting him or her to the network, even if that connection changes "seamlessly" mid-call.
Which is fine for the 1 time in a hundred that someone might start a phone call on WiFi & walk out the house and expect the call to just switch over without dropping. But useless (or possibly worse than useless) for many of the other use cases for dual-mode devices. "Seamless handover" is a nice-to-have - but only if it doesn't introduce problems elsewhere.
This all fits in with one of the biggest fallacies with IMS - that applications or services should be "bearer agnostic" - ie work the same, irrespective of whether they're connected over 2G, 3G, WiFi, WiMAX, ADSL or a piece of wet string. And that they should be able to switch over "in mid-flight".
This ignores the fact that at the "seam" lots of things change. Bandwidth, latency, price, maybe ownership, control, security, context and lots of other things. While the user should (in some cases like an ongoing voice call) have minimal interaction, the device itself and its resident applications need to be fully bearer-aware to enable a good user experience, especially for data applications. Moving from a low-latency to high-latency connection has a huge impact on software that has complex "hand-shaking" procedures, for example. And moving from an unlimited-data environment (eg home or office WiFi) to one that is tariffed per-MB clearly needs intervention. If I have anti-virus software, for example, I don't want it downloading 5MB of stuff unannounced, especially if I'm roaming. And I want the music application on the device to recognise I'm at home on WiFi, and default to getting MP3s from my PC hard drive, rather than defaulting to the operator music portal.
Generally, I deduct 2 "credibility points" per use of the word "seamless" in a vendor's or operators presentation or marketing material. (Almost as bad as single device / bill / number, in fact). "Ubiquitous", "Transparent", "Flexible" are all much better terms.
This isn't just me, by the way. I've heard very large operators agree that they want intelligent "bearer aware" applications on devices, not "bearer agnostic" ones. Moore's Law rules, as usual.
So it was interesting to be at a conference this morning and hear both BT and DT essentially start to redefine the term "seamless". Both speakers said that "seamless handover between bearers" was not essential - but that access to certain functions like address book or voicemail was. I agree with this - and if "seamless" is to be more generally used as a marketing-friendly way of saying "multi-access", I may reconsider my views about the credibility of its proponents.
It's still trite, though.