... DataLinkLayer Protocols- The Frame
31
• Remember that although there are many different DataLinklayerprotocols that describe
Data Linklayer frames, each frame ... this chapter, you will be able to:
• Explain the role of DataLinklayerprotocolsindata transmission.
• Describe how the DataLinklayer prepares data for transmission on
network media.
• ... very simple.
• In point-to-point networks, if data can only flow in one direction at a time, it is
operating as a half-duplex link. If data can successfully flow across the link
from each node...
... Session
Network
Data link
Physical
zone 1
zone 2
H2:H.323 Protocolsin relation to the OSI model
G.711
G.722
G.728
G.729
G.723.1.1
Presentation
H.261 ... H.323 RAS signaling
zone 1
zone 2
H×nh 3: kiÕn tróc t¹i Terminal H.323 cña Cisco
Video Conference Architecture
a typical H.323 Terminal
Video I/O
Equipment
Audio I/O
Equipment
User Data
Applications
System
Control
User
Interface
H.225.0
Layer
Locall
Area
Network
Intererface
recovery
Path
Delay
Video ... Data
Applications
System
Control
User
Interface
H.225.0
Layer
Locall
Area
Network
Intererface
recovery
Path
Delay
Video
codec
H261,
H263
Audio
condec
G711, G722,
G723, G728
G729
System control
1. Setup
2. Alerting
3....
... VHF Digital Link
Thuật ngữ VHF Digital Link được đề ra bởi hiệp hội thông tin di động hàng
không ICAO (AMCP) vào cuộc họp đầu tiên tháng 10 năm 1991, với những hệ thống
thông tin liên lạc số ... trên vùng lãnh thổ Việt Nam.
Luận văn “ ỨNG DỤNG CỦA VHF DATALINK MODE 4 TRONG MÔI TRƯỜNG CNS/
ATM ” nghiên cứu công nghệ kỹ thuật VHF DataLink Mode 4, một liên kết dữ liệu số
sử dụng sóng VHF ... (thoại và dữ liệu), và
VDL mode4 - (dữ liệu).
+ SSR Mode S - (dữ liệu)
+ HF Datalink – (dữ liệu).
Các dịch vụ thông tin cho phép các mạng dữ liệu điện tử hàng không, liên lạc
không/địa và địa/địa...
... remove existing records. The DataReader class will be examined to
retrieve the correct data into newly instantiated User objects in each of the Find* methods.
Listing 8–3. Database Interaction ... UserMapper(string connectionString)
{
_connectionString = connectionString;
}
private string _connectionString;
private IDbConnection _databaseConnection;
private bool ConnectToDatabase(string ... using either the
LINQ query syntax or the built -in IEnumerable extension methods (see Listing 8–5).
Listing 8–5. Access a User by Name Using Both Syntaxes
DataContext dataContext = new DataContext(connection);...
...
Editing Manager: Lynette Skinner
Editor: Mick Alberts, Jennifer Linn
Production Manager: Miracle Davis
Print Coordinators: Linda Lu Cannon (Write Stuff), Marlene Lambert (Online Training
Solutions, ...
To define how CRM is used
in the physical design.
Lead -in
In this topic, you will learn
how and when to include
CRM in your physical
design.
Module 9: The Transactional Data Access Layer ... Purchasing, as shown
in the preceding slide, incorporates several principles:
!
The Iterator design pattern is used to represent data sets.
!
There is one design class for each entity in the database....
... signaling protocols perform plays a
critical role in designing, building, maintaining, and troubleshooting a Cisco VoIP implementation. Each proto-
col also plays a direct role in implementing ... Bachelors of Science in Mechanical Engineering and a Masters of Science in Mechanical
Engineering from Bradley University in P
eoria,
IL.
Chris can be reached at chrisolsen@earthlink.net.
Copyright ... in product
selection and integration. Specifically, Cisco has predominately implemented the following five different signal-
ing protocols amongst their rapidly expanding telephony product line:
•...
...
PreRoutingQueue List of messages waiting for the advanced
queuing engine to determine the route.
Destination Queue List of messages currently being sent, or
waiting to be sent to a destination ...
f.
In the
My incoming mail server is a
drop-down box, click
IMAP
.
g.
In the
Incoming mail (POP3, IMAP or HTTP) server
box, type
your_servername.
nwtraders.msft
h.
In the
Outgoing ...
Next
.
b.
In the
E-Mail address
box, type your_username
@nwtraders.msft
and then click
Next
.
c.
In the
My incoming mail server is a
list, click
IMAP
.
d.
In the
Incoming mail (POP3,...
...
Editing Manager: Lynette Skinner
Editor: Mick Alberts, Jennifer Linn
Production Manager: Miracle Davis
Print Coordinators: Linda Lu Cannon (Write Stuff), Marlene Lambert (Online Training
Solutions, ... Nontransactional Data Access Layer
#
##
#
Introduction to the Data Access Layer
!
The Business Problem
!
Splitting the DAL
The DAL buffers the entire system from the underlying data services. ... to data services for creating, updating, or deleting is accomplished
through the DAL.
In this section, the DAL is introduced and discussed in the context of the
business problem for accessing...
... 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
... tra kết nối vật lý
– Click nút Start -> Run -> gõ lệnh cmd cửa sổ command line hiện ra -> gõ lệnh ping đến địa
chỉ IP của Default gateway mạng đơn vị mình ( Default gateway mạng 172.28.x.0 ... là 172.28.111.1
– Nếu thành công qua bước 2.
– Nếu không thành công :
+ Xem xét lại thông tin cấu hình mạng đã đúng chưa. Nếu sai thì thay đổi lại cho đúng và
thử lại bước 1.
...
... Purchasing
transactional DAL.
Module 9: The Transactional Data Access Layer 3
The Business Problem
DAL
Connected Business
Logic Layer
Disconnected Business
Logic Layer
Facade Layer
Web ...
Editing Manager: Lynette Skinner
Editor: Mick Alberts, Jennifer Linn
Production Manager: Miracle Davis
Print Coordinators: Linda Lu Cannon (Write Stuff), Marlene Lambert (Online Training
Solutions, ... define how CRM is used
in the physical design.
Lead -in
In this topic, you will learn
how and when to include
CRM in your physical
design.
28 Module 9: The Transactional Data Access Layer...
...
Recipe 1.13 Using the DataLink Properties Dialog Box
Problem
You want to display the DataLink Properties dialog
b
ox from an application so that users
can create their own database connections ... from the COM tab in Visual Studio .NET's Add Reference
Dialog.
The sample code contains a single event handler:
Data Link Dialog Button.Click
Creates and displays a DataLink Properties ... they can from the Server Explorer
window in the Visual Studio .NET IDE.
Solution
Use COM interop with the OLE DB Service Component to display the DataLink
Properties dialog box.
You'll...
... Balanced (LAPB)
Part of X.25 (ITU-T)
Subset of HDLC - ABM
Point to point link between system and packet
switching network node
Link Access Procedure, D-Channel
ISDN (ITU-D)
ABM
Always ...
i
Transmitter goes back to frame
i
and
retransmits
William Stallings
Data and Computer
Communications
Chapter 7
Data Link Control
Cyclic Redundancy Check
For a block of
k
bits transmitter ... -
Diagram
Flow Control
Ensuring the sending entity does not overwhelm
the receiving entity
Preventing buffer overflow
Transmission time
Time taken to emit all bits into medium
Propagation...
... 3.
11.2
11-1 FRAMING
11-1 FRAMING
The datalinklayer needs to pack bits into
The datalinklayer needs to pack bits into
frames
frames
, so
, so
that each frame is distinguishable from another. ... 11.40
The send window is an abstract concept
defining an imaginary box of size 2
m
− 1
with three variables: S
f
, S
n
, and S
size
.
Note
11.4
Figure 11.2 Byte stuffing and unstuffing
11.31
Algorithm ... frame is distinguishable from another. Our
postal system practices a type of framing. The simple
postal system practices a type of framing. The simple
act of inserting a letter into an envelope...
... C
Given an incoming packet with sequence # s, either
s in A – It's too old, and can be discarded
s in B – It's in the window. Check if it's been seen before
s in C – Shift the window ... the origin of the IP packet and ensure its integrity
To detect message replays using sliding window
Encapsulating security payload (ESP)
Encrypt and/or authenticate IP packets
Internet ... Remote Logins
J. Wang. Computer Network Security Theory and Practice. Springer 2009
PKIX Architecture
J. Wang. Computer Network Security Theory and Practice. Springer 2009
Key Determination and...