Acknowledgments are also used in su

Acknowledgments are also used in subsequent communications to ensure that data was properly delivered. For every data unit a node sends, its connection-oriented protocol expects an
acknowledgment from the recipient. For example, after a client’s TCP protocol issued an
HTTP request, it would expect to receive an acknowledgment from the Web server proving
that the data arrived. If data isn’t acknowledged within a given time period, the client’s
protocol assumes the data was lost and retransmits it.
To ensure data integrity further, connection-oriented protocols such as TCP use a checksum. A
checksumis a unique character string that allows the receiving node to determine if an arriving
data unit exactly matches the data unit sent by the source. Checksums are added to data at the
source and verified at the destination. If at the destination a checksum doesn’t match what
the source predicted, the destination’s Transport layer protocols ask the source to retransmit the
data. As you will learn, protocols at other layers of the OSI model also use checksums.
Not all Transport layer protocols are concerned with reliability. Those that do not establish a
connection before transmitting and make no effort to ensure that data is delivered free of errors
are calledconnectionlessprotocols. A connectionless protocol’s lack of sophistication makes it
more efficient than a connection-oriented protocol and renders it useful in situations in which
data must be transferred quickly, such as live audio or video transmissions over the Internet. In
these cases, connection-oriented protocols—with their acknowledgments, checksums, and flow
control mechanisms—would add overhead to the transmission and potentially bog it down. In
a video transmission, for example, this could result in pictures that are incomplete or aren’t
updated quickly enough to coincide with the audio.
In addition to ensuring reliable data delivery, Transport layer protocols break large data units
received from the Session layer into multiple smaller units, calledsegments. This process is known
as segmentation. On certain types of networks, segmentation increases data transmission
efficiency. In some cases, segmentation is necessary for data units to match a network’s MTU
(maximum transmission unit), the largest data unit it will carry. Every network type specifies a
default MTU (though its size can be modified to some extent by a network administrator). For
example, by default, Ethernet networks cannot accept packets with data payloads larger than 1500
bytes. Suppose an application wants to send a 6000-byte unit of data. Before this data unit can be
issued to an Ethernet network, it must be segmented into units no larger than 1500 bytes. To learn
anetwork’s MTU size (and thereby determine whether it needs to segment packets), Transport layer
protocols perform a discovery routine upon establishing a connection with the network. Thereafter,
the protocols will segment each data unit as necessary until closing the connection.
Segmentation is similar to the process of breaking down words into recognizable syllables
that a child uses when learning to read. Reassemblyis the process of reconstructing the
segmented data units. To continue the reading analogy, when a child understands the separate syllables, he can combine them into a word—that is, he can reassemble the parts into a
whole. To learn how reassembly works, suppose that you asked this question in history class:
“Ms. Jones? How did poor farming techniques contribute to the Dust Bowl?”but that the
words arrived at Ms. Jones’s ear as “poor farming techniques Ms. Jones? how did to the
Dust Bowl? contribute.”On a network, the Transport layer recognizes this kind of disorder
and rearranges the data pieces so that they make sense.
Sequencingis a method of identifying segments that belong to the same group of subdivided
data. Sequencing also indicates where a unit of data begins, as well as the order in which groups
of data were issued and, therefore, should be interpreted. While establishing a connection, the

Kết quả (Việt) 1:

Acknowledgments cũng được sử dụng trong truyền thông tiếp theo để đảm bảo rằng dữ liệu được chuyển giao đúng cách. Cho mỗi đơn vị dữ liệu một nút gửi, của nó giao thức kết nối theo định hướng hy vọng mộtsự thừa nhận từ người nhận. Ví dụ, sau khi một khách hàng của giao thức TCP ban hành mộtYêu cầu HTTP, nó sẽ hy vọng sẽ nhận được một sự thừa nhận từ các máy chủ Web chứng minhrằng các dữ liệu đến. Nếu dữ liệu không phải là thừa nhận trong một thời gian nhất định khoảng thời gian, khách hàng củagiao thức thừa nhận các dữ liệu bị mất và retransmits nó.Để đảm bảo tính toàn vẹn dữ liệu hơn nữa, kết nối theo định hướng giao thức như TCP sử dụng một kiểm tra. Achecksumis một chuỗi nhân vật duy nhất cho phép các nút nhận để xác định xem một đếnđơn vị dữ liệu chính xác phù hợp với các đơn vị dữ liệu được gửi bởi nguồn. Khả được bổ sung vào dữ liệu tại cácnguồn và xác nhận tại các điểm đến. Nếu tại các điểm đến một checksum không khớp với những gìnguồn dự đoán, các điểm đến vận tải lớp giao thức yêu cầu nguồn retransmit nhữngdữ liệu. Như bạn sẽ tìm hiểu, giao thức tại các lớp khác của mô hình OSI cũng sử dụng khả.Không phải tất cả vận tải lớp giao thức có liên quan với độ tin cậy. Những người không thiết lập mộtCác kết nối trước khi truyền và làm cho không có nỗ lực để đảm bảo rằng dữ liệu được phân phối miễn phí của lỗilà calledconnectionlessprotocols. Một giao thức connectionless thiếu tinh tế làm cho nóhiệu quả hơn so với một giao thức kết nối theo định hướng và làm cho nó hữu ích trong các tình huống trong đódata must be transferred quickly, such as live audio or video transmissions over the Internet. Inthese cases, connection-oriented protocols—with their acknowledgments, checksums, and flowcontrol mechanisms—would add overhead to the transmission and potentially bog it down. Ina video transmission, for example, this could result in pictures that are incomplete or aren’tupdated quickly enough to coincide with the audio.In addition to ensuring reliable data delivery, Transport layer protocols break large data unitsreceived from the Session layer into multiple smaller units, calledsegments. This process is knownas segmentation. On certain types of networks, segmentation increases data transmissionefficiency. In some cases, segmentation is necessary for data units to match a network’s MTU(maximum transmission unit), the largest data unit it will carry. Every network type specifies adefault MTU (though its size can be modified to some extent by a network administrator). Forexample, by default, Ethernet networks cannot accept packets with data payloads larger than 1500bytes. Suppose an application wants to send a 6000-byte unit of data. Before this data unit can beissued to an Ethernet network, it must be segmented into units no larger than 1500 bytes. To learnanetwork’s MTU size (and thereby determine whether it needs to segment packets), Transport layerprotocols perform a discovery routine upon establishing a connection with the network. Thereafter,the protocols will segment each data unit as necessary until closing the connection.Segmentation is similar to the process of breaking down words into recognizable syllablesthat a child uses when learning to read. Reassemblyis the process of reconstructing thesegmented data units. To continue the reading analogy, when a child understands the separate syllables, he can combine them into a word—that is, he can reassemble the parts into awhole. To learn how reassembly works, suppose that you asked this question in history class:“Ms. Jones? How did poor farming techniques contribute to the Dust Bowl?”but that thewords arrived at Ms. Jones’s ear as “poor farming techniques Ms. Jones? how did to theDust Bowl? contribute.”On a network, the Transport layer recognizes this kind of disorderand rearranges the data pieces so that they make sense.Sequencingis a method of identifying segments that belong to the same group of subdivideddata. Sequencing also indicates where a unit of data begins, as well as the order in which groupsof data were issued and, therefore, should be interpreted. While establishing a connection, the