July 9, 2007

Presence is not an Identity feature

I realized in my "Unique Visitors" post that I skipped some background - didn't "show my work" as every math teacher I had always said.

When Google released GTalk, I remember feeling like they had missed an opportunity to correct the
Presence, Identity, Messaging and Accounts model - that they should have made "location" more than just metadata, but I don't think that's right, actually.

On the PC side of the Instant Messaging (IM) universe, Presence is exerted by an Identity, and (nowadays) often qualified by Location (for Location Based Services) and/or Network of Origin (for interoperation messaging systems), but I think Presence, especially for Comcast, is really a device feature, and Identities are transiently bound to those devices, generally with an (essentially) eternal TTL (time-to-live), though in the case of PCs, that TTL amounts to IM session length.

Identity is a kind of user virtualization construct (usually reasonably synonymous with "Credentials": username and password - at least for our purposes), while Presence advertises availability for messaging, and Messaging is generally a point-to-point session negotiation and communication pipe, though it may be one-to-many (broadcast), or many-to-many (chat). Note that Messaging and Presence need not necessarily be interdependent. Finally, Accounts are a billing relationship construct.

A typical use case in a househould is likely to involve multiple STBs (set top box or other consumer electronics device on the Comcast networks), multiple .net IDs (e-mail addresses), and multiple PCs in the house, where Presence, Identity, Message and Accounts overlap each. And of course, wireless, school/office, and multiple residences complicate the picture.

Usually, scalability for Presence is scale limited by subscription/notfication events, and by that I mean the "m X n" implied by the "Buddy List" construct, where any user may be subscribed to presence notification of any n users (effectively O(n^2) ). Messaging is bound by active simultaneous communication sessions (and type - multimedia for example) and is usually O(n).

In any case, I'm just rambling now - all of that's a roundabout way of saying that messaging is a service feature, not a product :)

18 comments:

bez said...

you're still alive? Who knew!

Sree Kotay said...

look who's talking, web boy :)

Anonymous said...

Hmmmm... You probably want to know the identity of the person currently linked to a device...

So, is the device state an attribute/metadata element linked to one's identity or is identity an attribute/metadata element linked to who's a device?

OnlinePharmacy said...

HyKYbB Your blog is great. Articles is interesting!

directory of phentermine on the net said...

T7Uu6o Thanks to author.

cheapest price for meridia said...

actually, that's brilliant. Thank you. I'm going to pass that on to a couple of people.

carroll motel said...

Please write anything else!

name said...

Hello all!

bruce springsteen devils dust tour said...

Please write anything else!

astana exits tour said...

Good job!

bests reccommended insuran said...

Thanks to author.

ringtones said...

Good job!

said...

Nice Article.

fioricet intrackbackaspx said...

EpDERc Hello all!

free ringtones for said...

Please write anything else!

Anonymous said...

runescape money runescape gold runescape money runescape gold wow power leveling wow powerleveling Warcraft Power Leveling Warcraft PowerLeveling buy runescape gold buy runescape money runescape items runescape gold runescape money runescape accounts runescape gp dofus kamas buy dofus kamas Guild Wars Gold buy Guild Wars Gold runescape accounts buy runescape accounts runescape lotro gold buy lotro gold lotro gold buy lotro gold lotro gold buy lotro gold lotro gold buy lotro gold runescape money runescape power leveling runescape money runescape gold dofus kamas cheap runescape money cheap runescape gold Hellgate Palladium Hellgate London Palladium Hellgate money Tabula Rasa gold tabula rasa money 压力开关 压力传感器 流量开关 流量计 液位计 液位开关 温湿度记录仪 风速仪 差压开关 可燃气体检测仪 过滤器 强磁水处理器 自清洗过滤器 自动反冲洗过滤器 保鲜棕榈树 棕榈树

runescape gold said...

runescape money runescape gold runescape gold runescape money buy runescape gold buy runescape money runescape money runescape gold wow power leveling wow powerleveling Warcraft Power Leveling Warcraft PowerLeveling buy runescape gold buy runescape money runescape itemsrunescape accounts runescape gp dofus kamas buy dofus kamas Guild Wars Gold buy Guild Wars Gold lotro gold buy lotro gold lotro gold buy lotro gold lotro gold buy lotro gold runescape money runescape power leveling runescape money runescape gold dofus kamas cheap runescape money cheap runescape gold Hellgate Palladium Hellgate London Palladium Hellgate money Tabula Rasa gold tabula rasa money Tabula Rasa Credit Tabula Rasa Credits Hellgate gold Hellgate London gold wow power leveling wow powerleveling Warcraft PowerLeveling Warcraft Power Leveling World of Warcraft PowerLeveling World of Warcraft Power Leveling runescape power leveling runescape powerleveling eve isk eve online isk eve isk eve online isk tibia gold Fiesta Silver Fiesta Gold




runescape money runescape gold wow power leveling


棕榈树
VI设计
画册设计
血管瘤
肝血管瘤
音乐剧
福卡
防静电地板
美国留学
留学美国
电阻器
不锈钢电阻器
频敏电阻器

睡眠呼吸机
伟康呼吸机
呼吸机
无创呼吸机
家用呼吸机
呼吸机的使用

北京消化系统疾病
北京心脑血管疾病
北京肾病
北京中医儿科
北京针灸减肥
针灸减肥
北京糖尿病
北京疼痛病
北京类风湿

筱娅 said...

Do you like playing the game where you need to use flyff penya, when you do not have flyff money, you must borrow flyff gold from friends, or you buy flyff penya. If you get cheap penya, you can continue this game.