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Communication State Transitions

Well, if the bandwidth is so much greater when connected than otherwise, why do we even bother? Well, we want mobility and as they put in [24]:

"...with an increasing degree of mobility, the bandwidth of a connection, and as a consequence the amount of data which can be transferred in adequate time, decrease."

Figure 2.1: Different states
States

Furthermore, disconnected operation may be the result of a network or communication media failure that makes it impossible for the client to stay in contact with the server--an unvoluntary disconnection. The transitions between communication states are shown in Figure 2.1. The transitions between connected and weakly connected are not so common; normally the user of the mobile computer makes a voluntary disconnection before traveling from one place (domain) to another, and then reconnects on arrival. The use of mobile computers is discussed in Section 2.3. As mentioned earlier, (see page [*]) the mobile clients should experience no degradation of consistency when fully connected, and thus consistency should be restored upon reentering connected mode of operation.


next up previous contents index
Next: Mobility Up: Means of Communication Previous: Disconnected   Contents   Index

michael@garfield.dk
2000-10-13