Session and GUID

admin — Mon, 31 Aug 2009 22:56:04 +0000

What is session? Definitely it is a period of time. In case of web, we can define session as period of time when an Internet user interacts with a particular web page or web application. The session is identified by GUID (Globally Unique Identifier). GUID is a special type of 128 bit identifier. That is it can identify 2 to the power 128 unique Internet user. The world does not have too many Internet user as the GUID can generate as many ids. So according to Pigeon Hole Principle, there is at least 0 id that is possessed by two unique users.

What will happen if the number of Internet user reaches or crosses the number 2 to the power 128? Well in this case according to Pigeon Hole Principle, more than one user can have the same id. But we have a lot of computer geeks and engineers. We already have 64 bit processor. Our genius computer scientist will raise the GUID to 256 bit from 128 bit. It is a very easy task to generate 256 bit id using our current processor let alone our future processor. I think it will take some centuries to reach 2 to the power 128 Internet user let alone 2 to the power 256. The number of current Internet user is about 1,668,870,408 . I get this data from InternetWorldStat.com.

2 to the power 128 equals to 340,282,366,920,938,463,463,374,607,431,768,211,456. I don’t know how many centuries will pass to reach this number. So till then the GUID will provide us a unique 128 bit id for each unique Internet user.

Life and Living » Globally Unique Identifier

Session and GUID