Ví dụ về việc sử dụng State server trong Tiếng anh và bản dịch của chúng sang Tiếng việt
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Each state server has requests waiting to be processed.
You can now test andrun any web applications you have with the running state server.
State servers 1 and 2 issue broadcasts requesting a session transfer.
Various programming techniquesare used to implement different aspects of the state server.
Peer state servers also act as a security layer that protects session data on the network.
Two web servers connect across the public internet to access a state server.
Requests on state server 3 that were not processed will wait until the transfer is complete.
Thirdly, an issue that many developersare unaware about is that the web server and state server communicate in plain text.
However the peer to peer state server can be configured to transmit encrypted data between peers.
NET web developers have three built in options to store session state, namely, in-process memory,SQL Server and State Server.
The state server is unaware that the web server has discarded those requests and still proceeds to process them.
Firstly, several web servers typically depend on one state server for session state which introduces a critical single point of failure.
Peer state servers also mutually authenticate each other while connecting, to ensure that the other party is an authorized peer.
This effectively thwarts network eavesdropping attacks if web server andassociated state servers are installed on the same computer or on a trusted network.
The state server is written in C 2.0, but targets the NET 3.5 framework so as to take advantage of the ReaderWriterLockSlim class.
This may not be a threat if all servers are running in an internal network butit is certainly cause for concern when web servers and state servers are spread across the internet.
You can start the state server on the computer and it will link up with the other state server(s) on the network.
The transfer process is relatively slow and since all requests have towait to be processed one at a time by each state server, requests start to time out and the web server starts discarding requests.
The peer to peer state server is fully backward compatible with the Microsoft provided state server and comes with all the benefits mentioned earlier.
This goes on and on and the servers keep transferring the session amongst themselves while most of the requests wait,because even when a session is transferred, the state server is only able to process a few requests before it is transferred to another state server.
All these techniques employed by the state server can only adversely affect the web application of the offending user.
The Peer to Peer State Server works exactly as illustrated above, except when the state server doesn't have the requested session state, in which case it requests the session state from the network before responding, as illustrated below.
Furthermore, if a load balancer erroneously or intentionally redirects a user to adifferent web server attached to a separate state server, the user's session state will be requested from the state server that served the user's previous request.
Data transfers between the web server and the state server remain unencrypted but eavesdropping attacks can be eliminated by keeping web servers and linked state servers in trusted networks or on the same computer.
If the new web server communicates with a different state server, the user's original session state will not be found and the web application may not work properly.
To make matters worse, if a state server receives a GetTransferMessage message after it has recently transferred the session, it rebroadcasts the message(as explained earlier), which leads to even more GetTransferMessage broadcasts on the network, more back-and-forth transfers and prolonged resource starvation.
If the requested session state isnot transferred within a set time period, the state server assumes the session state does not exist on the network and proceeds to process the web server request without the session state. .
While it may beimpossible to stop any group of users from flooding the state server with requests, the state server guards against contentious sessions with the following principle: any degradation of service due to a contentious session should mainly affect the user of that session, and achieves this goal with the following mechanisms.
For example, consider a network of three state servers as shown below, each state server on each machine would have the configuration shown below.
A broadcast that originated from state server 1 reaches state server 2 andthe session is transferred to state server 1.