Accessing the WAN, CCNA Exploration Companion Guide in Java Creation 3 of 9 barcode in Java Accessing the WAN, CCNA Exploration Companion Guide

Accessing the WAN, CCNA Exploration Companion Guide using tomcat toassign code 39 full ascii on web,windows application iPhone In Figure 2- Code 39 Extended for Java 2, notice that the bits of the parallel connection do not arrive at the same time due to clock skew.. Figure 2-2. Byte Clock Skew Parallel Communication b1 b2 b3 b4 b5 b6 b7 b8 Bytes Received Byte Parallel wir es are physically bundled in a parallel cable, and signals can imprint themselves on each other, making the cable more susceptible to crosstalk. The possibility of crosstalk across the wires requires more processing, especially at higher frequencies. The serial buses on computers and routers compensate for crosstalk before transmitting the bits.

Because serial cables have fewer wires, less crosstalk occurs, and network devices transmit serial communications at higher, more efficient frequencies. In Figure 2-3, bits 1, 2, 7, and 8 are experiencing some crosstalk, but bits 5 and 6 are not. Bits 3 and 4 have encountered too much crosstalk and therefore are dropped.

. Figure 2-3. Byte Crosstalk Parallel Com munication b1 b2 Bytes Received b3 b4 b5 b6 b7 b8 At higher frequencies, crosstalk causes bytes to be dropped. Byte. In most case bar code 39 for Java s, serial communications are considerably cheaper to implement. Serial communications use fewer wires, cheaper cables, and fewer connector pins..

2: PPP Serial Communication Standards All long-hau l communications and most computer networks use serial connections, because the cost of cable and synchronization difficulties makes parallel connections impractical. The most significant advantage is simpler wiring. Also, serial cables can be longer than parallel cables, because much less interaction (crosstalk) occurs among the conductors in the cable.

In this chapter, we will confine our consideration of serial communications to those connecting LANs to WANs. Figure 2-4 is a simple representation of serial communication. The sending router encapsulates the data using PPP.

The encapsulated PPP frame is sent on a physical medium to the WAN. There are various ways to traverse the WAN, but the receiving router uses the same communications protocol to unencapsulate the frame when it arrives..

Figure 2-4 Serial Communication WAN 011111100110 1110 Frame Being Sent Physical Medium 011 Frame Being Received Data to Be Encapsulated Unencapsulated Data to Be Data Encapsulated There are ma Code 3/9 for Java ny different serial communication standards, each one using a different signaling method. Three key serial communication standards affect LAN-to-WAN connections:. RS-232: Most serial ports on PCs conform to the RS-232C standard or the newer RS422 and RS-423 standards. Although the standard defines a nine-pin connector and a 25-pin connector, the nine-pin connector is more commonly implemented. A serial port is a general-purpose interface that can be used for almost any type of device, including modems, mice, and printers.

Many network devices use RJ-45 connectors that also conform to the RS-232 standard. Figure 2-5 shows an RS-232 connector. V.

35: Typically used for modem-to-multiplexer communication, this ITU standard for high-speed, synchronous data exchange combines the bandwidth of several telephone. Accessing the WAN, CCNA Exploration Companion Guide circuits. In the United States, V.35 is the interface standard used by most routers and DSUs that connect to T1 carriers.

V.35 cables are high-speed serial assemblies designed to support higher data rates and connectivity between DTEs and DCEs over digital lines. You ll read more about DTEs and DCEs later in this section.

. HSSI: A High jar 3 of 9 -Speed Serial Interface (HSSI) supports transmission rates of up to 52 Mbps. Engineers use HSSI to connect routers on LANs with WANs over high-speed lines such as T3 lines. Engineers also use HSSI to provide high-speed connectivity between LANs, using Token Ring or Ethernet.

HSSI is a DTE/DCE interface developed by Cisco Systems and T3plus Networking to address the need for high-speed communication over WAN links.. Nine-Pin RS-232 Connector Pin 1 Data C tomcat Code-39 arrier Detect (DCD) (Not Used). Figure 2-5. Pin 2 Receiv j2ee Code 3 of 9 e Data (RD) Pin 3 Transmit Data (TD) Pin 4 Data Terminal Ready (DTR) (Not Used). Pin 5 Ground Pin 8 Clear tomcat barcode code39 to Send (CTS) Pin 6 Data Set Ready (DSR) (Not Used) Pin 7 Request to Send (RTS). Pin 9 Ringin g Indicator (RI) (Not Used). As well as u jdk Code 3/9 sing different signaling methods, each of these standards uses different types of cables and connectors. Each standard plays a different role in a LAN-to-WAN topology. This course does not examine the details of V.

35 and HSSI pinning schemes. However, a quick look at a nine-pin RS-232 connector used to connect a PC to a modem helps illustrate the concept, as shown in Figure 2-5. A later section looks at V.

35 and HSSI cables.. Pin 1: Data Carrier Detect (DCD) indicates that the carrier for the transmit data is ON. Pin 2: The receive pin (RD) carries data from the serial device to the computer..

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