the data link layer

... Data Link Layer Protocols- The Frame 31 • Remember that although there are many different Data Link layer protocols that describe Data Link layer frames, each frame ... able to: • Explain the role of Data Link layer protocols in data transmission. • Describe how the Data Link layer prepares data for transmission on network media. • Describe the different types ... between the nodes of a network independent of their physical layout. – These logical signal paths are defined by Data Link layer protocols. • The Data Link layer "sees" the logical...

Ngày tải lên: 22/12/2013, 13:17

Ngày tải lên: 26/01/2014, 10:20

... satisfy the requirements of the Create Requisition use case. In the class, include the necessary methods to obtain the next database ID. The class should also cache database IDs from the database ... outcome of the transaction. Operation of CRM The first step in the operation of the CRM is the client component’s creation of the CRM Worker. The client component then begins using the CRM Worker. ... that focus on the DAL: Module 8, The Nontransactional Data Access Layer and Module 9, The Transactional Data Access Layer. ” The DAL is an application’s means of access to data services....

Ngày tải lên: 05/11/2013, 12:15

... Nontransactional Data Access Layer 43 Security ! Connecting to the Database ! Creating Security Roles Like the other layers, the DAL also requires secure access. Connecting to the Database The ... about the architecture of OLE DB. 2 Module 8: The Nontransactional Data Access Layer # ## # Introduction to the Data Access Layer ! The Business Problem ! Splitting the DAL The DAL ... the database. Also, the cursor does not track changes to the underlying data. This is useful if you need an unchanging snapshot of the data. 30 Module 8: The Nontransactional Data Access Layer...

Ngày tải lên: 21/12/2013, 06:17

Ngày tải lên: 17/01/2014, 09:20

Ngày tải lên: 21/06/2014, 22:20

... sent at t 0 collides with other frames sent in [t 0 -1,t 0 +1] 5: DataLink Layer 5-2 Chapter 5: The Data Link Layer Our goals: ❒ understand principles behind data link layer services: ❍ error ... node ❒ adapter is semi- autonomous ❒ link & physical layers sending node frame rcving node datagram frame adapter adapter link layer protocol 5: DataLink Layer 5-36 Link Layer ❒ 5.1 Introduction and ... channel: multiple access ❍ link layer addressing ❍ reliable data transfer, flow control: done! ❒ instantiation and implementation of various link layer technologies 5: DataLink Layer 5-49 Star topology ❒ Bus...

Ngày tải lên: 12/09/2012, 15:06

... + HF – (thoại tương tự) + VHF Data link: VDL Mode2 – (dữ liệu), VDL mode3 - (thoại và dữ liệu), và VDL mode4 - (dữ liệu). + SSR Mode S - (dữ liệu) + HF Data link – (dữ liệu). Các dịch vụ thông ... trên vùng lãnh thổ Việt Nam. Luận văn “ ỨNG DỤNG CỦA VHF DATA LINK MODE 4 TRONG MÔI TRƯỜNG CNS/ ATM ” nghiên cứu công nghệ kỹ thuật VHF Data Link Mode 4, một liên kết dữ liệu số sử dụng sóng VHF ... phát theo các bậc 25W phụ thuộc vào ứng dụng mà máy phát đáp sử dụng. Mặc dù là trạm mặt đất, nhưng các trạm vẫn quảng bá vị trí của trạm theo những khoảng thời gian đều đặn. Để đạt được theo...

Ngày tải lên: 22/11/2012, 09:13

Ngày tải lên: 23/08/2013, 10:37

Ngày tải lên: 05/09/2013, 08:40

... perform the CRUD operations required by the clients of the model—most likely to be the ViewModel. The objective of the DAL code is to protect the object schema from changes to the database ... returned. The FindAll method, on the other hand, returns every user in the database without discrimination. CHAPTER 8 ■ DATA ACCESS LAYER 177 Figure 8–7. The LINQ-to-SQL mapping of the e-commerce ... all of the address data in the Customer table. The objects may be retrieved with a composition relationship, but the database itself ignores that and stores the data in a single table. The final...

Ngày tải lên: 03/10/2013, 01:20

... The weakest link If you consider the entire structured cabling Channel, from the PC to the switch, the weakest link is the modular plug. This is the point that has the potential for the lowest performance. ... a small space, they are crossed over each other and split, and then they are put in parallel with flat plates. Often, mechanical crimps are used to hold the cable in the plug. These crimps can ... stranded cable. And just where are these patch cords located? They are the closest parts of the structured cabling system to the active components. They are placed where the outbound signals strengths...

Ngày tải lên: 26/10/2013, 19:15

... in the database until it is needed. For example, you must decide whether to hold the unit price of an item in the cart or retrieve this directly from the database when the user proceeds to the ... in the back end. The disadvantages are:  The database resources required in storing state information  The computing cost that is incurred by frequently moving data from the client to the ... the ASP.NET session is stored externally from the worker process, the state data can be accessed by another worker process. These worker processes could be running on another processor on the...

Ngày tải lên: 10/12/2013, 16:16

... process the request when the call returns:  The return value of the method call does not reflect the success or failure of the call on the server. Therefore, there is no way to inform the caller ... for the functioning of OPP is the OrderForm object. This provides the link between the e-commerce site and the objects running in the pipeline. As users browse the site and make changes to their ... redirect the user again when the user has been successfully authenticated. 2. After the Passport site successfully authenticates a user, the user is re-directed back to the merchant’s site with the...

Ngày tải lên: 10/12/2013, 16:16

Ngày tải lên: 10/12/2013, 19:15

... to fill a DataSet, the column names used in the DataSet default to the column names defined in the data source. A DataAdapter has a collection of DataTableMapping objects in its DataTableMappingCollection ... DataSet changes back to the data source. In the solution, the Categories table retrieved by the query is mapped to a table in the DataSet called tblmapCategories with the following code: DataTableMapping ... tables created within the DataSet to match the table names in the data source or to map the tables returned from a batch query to DataTable objects that already exist within the DataSet. Each table...

Ngày tải lên: 14/12/2013, 18:16

... trường hợp về sự cố mạng có thể do phần cứng hay phần mềm: Phần cứng (Lớp Physical, Data Link) : Đèn liên kết (Link ) của card mạng không sáng Kiểm tra đầu nối card mạng và đầu cáp nối trên HUB/SWITCH ...

Ngày tải lên: 23/12/2013, 03:17

... Choosing the data connection 7. Click the Next button to continue. 8. You now log in to the database by specifying the password for the database user. You used the sa user when creating the database ... that the top part of the form shows the details for the row from the Customers table where the CustomerID is ALFKI; the bottom part of the form contains a DataGrid control that displays the ... select the database tables or views you want to use in your form. The area on the bottom left of the dialog box shows the tables and views you can access using your form. The area on the bottom...

Ngày tải lên: 24/12/2013, 01:17

... column in a DataSet object, the value for that column is displayed in the control through the Text property in the DataBindings group. The Text property in the DataBindings group sets the text ... set the data binding for a control, you select the control in the form designer and expand the DataBindings properties in the Properties window. You'll see these properties in the Data ... display the new form, as shown in Figure 6.26 . Notice that the top part of the form shows the details for the row from the Customers table where the CustomerID is ALFKI; the bottom part of the...

Ngày tải lên: 24/12/2013, 01:17