Www.ciscopress.com Copyright 2003 CCNA 2 Chapter 17 TCP/IP Suite Error and Control Messages By Your Name. - презентация

1 Copyright 2003 CCNA 2 Chapter 17 TCP/IP Suite Error and Control Messages By Your Name

2 Copyright 2003 Objectives TCP/IP error messages TCP/IP control messages

3 Copyright 2003 ICMP

4 Copyright 2003 Error Reporting and Error Correction ICMP is an error-reporting protocol for IP. When datagram delivery errors occur, ICMP is used to report these errors back to the sender of the datagram.

5 Copyright 2003 ICMP Message Delivery ICMP messages are encapsulated as data in datagrams in the same way any other data is delivered using IP.

6 Copyright 2003 ICMP Testing

7 Copyright 2003 Ping

8 Copyright 2003 Ping with DNS

9 Copyright 2003 Detecting Long Routes Whether the actual path includes too many hops or a circular routing path exists, the packet will eventually reach the end of its life, known as its time-to-live (TTL).

10 Copyright 2003 Echo Messages ICMP message formats start with these same three fields: Type Code Checksum

11 Copyright 2003 Destination Unreachable Messages

12 Copyright 2003 TCP/IP Suite Control Messages

13 Copyright 2003 Control Messages They are used to inform hosts of conditions such as network congestion or the existence of a better gateway to a remote network.

14 Copyright 2003 Redirect/Change Requests All hosts that communicate with multiple IP networks must be configured with a default gateway. This default gateway is the address of a router port connected to the same network as the host.

15 Copyright 2003 Clock Synchronization and Transit- Time Estimation Hosts on disparate networks who are trying to communicate using software that requires time synchronization. The ICMP time-stamp request message allows a host to ask for a remote hosts current time.

16 Copyright 2003 Address Mask Requirements When a network administrator uses the process of subnetting to divide a major IP address into multiple subnets, a new subnet mask is created.

17 Copyright 2003 Router Discovery Message

18 Copyright 2003 Congestion and Flow Control Congestion can also occur when traffic from a high-speed LAN reaches a slower WAN connection.