Có 100+ tài liệu thuộc chủ đề "định tuyến giao thức"
tailieu.vn Xem trực tuyến Tải xuống
An administrative distance of 15 indicates which of the following?. Identify a variety of ICMP control messages used in networks today. Determine the causes for ICMP control messages. TCP/IP Error and Control Messages. 762 Chapter 17: TCP/IP Error and Control Messages. ICMP notifies the sender of the data that an error occurred in the delivery process.. Knowledge of ICMP error...
tailieu.vn Xem trực tuyến Tải xuống
In another situation, no path exists between the source and the destination that conforms to the limitations of the routing protocol. An example of the first situation arises when two routers contin- ually route a datagram back and forth. In this scenario, each router operates with the understanding that the other router should be the next hop to the destination....
tailieu.vn Xem trực tuyến Tải xuống
If a router-solicitation message is sent to a router that does not support the discovery process, the solicitation will go unanswered.. Table 17-7 provides an explanation for each field of the frame format.. Checksum The 16-bit 1s complement of the 1s complement sum of the ICMP message starting with the ICMP type. The number of the address interface from which...
tailieu.vn Xem trực tuyến Tải xuống
With a structured approach, members of the network know what each member has completed to solve a problem. Layer 1 OK?. No Fix Layer 1. Layer 2 OK?. No Fix Layer 2. Layer 3 OK?. No Fix Layer 3. Layer 4 OK?. No Fix Layer 4. Layer 5 OK?. No Fix Layer 5. Layer 6 OK?. No Fix Layer 6....
tailieu.vn Xem trực tuyến Tải xuống
If the line is down, a problem with the cabling might exist in a back-to-back connection, with one end being “administratively down.” If the interface is administratively down, it has been disabled manually in the configuration.. The show interfaces serial command also provides information to help diagnose other Layer 1 issues that are not as easy to determine.. Example 18-3...
tailieu.vn Xem trực tuyến Tải xuống
To disable a particular debug command, use the no form of the command. The traceroute command can be used to determine the status of links between routers. The show ip route and show ip protocol commands help to identify routing issues.. Telnet Standard terminal-emulation protocol in the TCP/IP protocol suite. Complete all the review questions to test your understanding of...
tailieu.vn Xem trực tuyến Tải xuống
Figure 19-3 Transport Layer Protocols. Connection-oriented means that the end stations are aware of each other and are constantly communicating about the con- nection. postal service where once you place the letter in the mail you hope that the mailing process gets the package delivered. Figure 19-4 illustrates the TCP seg- ment header format, the field definitions of which are...
tailieu.vn Xem trực tuyến Tải xuống
because both SMTP and the World Wide Web services use TCP as their transport layer protocol. A method to separate transport layer conversations must be used.. Hosts running TCP/IP associate ports at the transport layer with certain applications.. Port numbers are used to keep track of different conversations that cross the network at the same time. Port numbers are necessary...
tailieu.vn Xem trực tuyến Tải xuống
1102.book Page 839 Tuesday, May PM. 1102.book Page 840 Tuesday, May PM. Access Control Lists. Network administrators must be capable of denying unwanted access to the network while allowing appropriate access. For exam- ple, a network administrator might want to allow users access to the Internet but might not want external users Telnetting into the LAN.. An ACL is a...
tailieu.vn Xem trực tuyến Tải xuống
Figure 20-6 Wildcard Mask Bit Matching. A wildcard mask is paired with an IP address, similar to how a subnet mask is paired with an IP address. Wildcard mask bits use the numbers 1 and 0 to identify how to treat the corresponding IP address bits.. The term wildcard masking is a nickname for the ACL mask bit–. Recall that...
tailieu.vn Xem trực tuyến Tải xuống
log The message includes the access list number, whether the packet was permitted or denied. Use the ip access-list log-update command to gener- ate logging messages when the number of matches reaches a configurable threshold (instead of waiting for a 5-minute interval). See the ip access-list log- update command for more information.. Therefore, the logging facility should not be used...
tailieu.vn Xem trực tuyến Tải xuống
For security purposes, users can be denied or permitted virtual terminal access to the router, but denied access to destinations from that router. For example, an administrator can configure the ACL to allow terminal access to the router for management or troubleshooting purposes, while at the same time restricting access beyond this router.. vty access is accomplished using the Telnet...
tailieu.vn Xem trực tuyến Tải xuống
Structured Cabling. Structured cabling systems, standards, and codes. Tools of the trade. Completing this material and the associated labs in the Cisco Networking Academy Program CCNA 1 and 2 Lab Companion, Third Edition, will provide a broad introduction to all facets of structured cabling installation.. Structured Cabling Systems, Standards, and Codes. Structured cabling systems refer to telecommunications wiring built in...
tailieu.vn Xem trực tuyến Tải xuống
Structured Cabling Systems, Standards, and Codes 889. Servicing the Work Area. It is much easier to patch cable from the work area outlet to a new position in the TR than it is to remove terminated wires from connected hardware and reterminate them to another circuit. Patch cords also are used to connect networking equipment to the cross-connects in a...
tailieu.vn Xem trực tuyến Tải xuống
Both the TIA and the EIA are accredited by the American National Standards Institute (ANSI, section 6.2.7) to develop voluntary industry standards for a wide variety of telecommunications products. TIA/EIA. The various committees and subcommittees of TIA/EIA develop standards for fiber optics, user premises equipment, network equipment, wireless communications, and satellite communications.. Figure A-14 TIA/EIA Structured Cabling Standards. TIA/EIA 568-A...
tailieu.vn Xem trực tuyến Tải xuống
A device such as a switch or a router might have a bonding strap between its case and a ground circuit to ensure a good connection.. Maintain the integrity of the electrical grounding plant. Telecommunications bonds typically are used in the following ways:. It also specifies the necessary grounding and bond- ing configurations needed in the building to support this...
tailieu.vn Xem trực tuyến Tải xuống
A measuring wheel is used to estimate the length of a cable run (see Figure A-24). The wheel has a counter mounted on the side. An installer simply rolls the wheel down the intended path of the cable. When the end is reached, the counter indicates the distance.. Cleanup is one of the final but important steps in completing a...
tailieu.vn Xem trực tuyến Tải xuống
Before cutting into the wall, use a carpenter’s level to make sure the opening will be straight. Push the knife through the drywall, inside the template outline, until you have an opening large enough to accommodate the blade of either a keyhole saw or a drywall saw.. Insert the saw into the hole, and cut along the edge of the...
tailieu.vn Xem trực tuyến Tải xuống
In the rough-in phase of cable installation, excess cable was left at both ends of the cable run. It is not uncommon to have 1m (3 ft.) of ends hanging out of a wall jack at the finish of the rough-in stage. In the telecommunications room (TR), where hundreds of cables are terminated, it is not uncommon to have 2m...
tailieu.vn Xem trực tuyến Tải xuống
Two methods are used when testing: the channel test and the link test. The channel test goes truly end-to-end from the workstation or telephone to the device in the telecom- munications room (TR). The channel test measures all of the cable and patch cords, including the line cord from the jack to the user equipment and the patch cord from...