CCNA全版PPT 1-05-IP.ppt

1、 2003, Cisco Systems, Inc. All rights reserved.,Module : TCP/IP,Network Layer Protocol Overview,Objectives,Name two protocols that operate at the network layer Identify three functions of the IP protocol Identify three functions of the ICMP protocol Identify a function of both ARP and RARP Identify

2、the function of DHCP Identify three fields in an IP datagram Describe the function of the protocol field in an IP datagram,Network Layer,Application,Transport,Data Link,Physical,Network,Internet Protocol (IP) Internet Control Message Protocol (ICMP) Address Resolution Protocol (ARP) Reverse Address

3、Resolution Protocol (RARP) Dynamic Host Configuration Protocol (DHCP),IP Characteristics,Packets are treated independently,Packet delivery is not guaranteed,Lost or corrupted packets are not recovered,ICMP,Application,Transport,Data Link,Physical,Network,Destination unreachable Echo (Ping) Other,ARP

4、,IP: 172.16.3.2 = ?,IP: 172.16.3.2 = Ethernet: 0800.0200.1111,Map IP,Ethernet,Local ARP,I heard thatbroadcast. That is me.Here is my MACaddress.,I need theMAC addressof 172.16.3.2,RARP,Maps Ethernet IP,Ethernet: 0800.0020.1111IP: ?,Ethernet: 0800.0020.1111IP: 172.16.3.25,I heard thatbroadcast. Your

5、IP address is172.16.3.25,What is my IPaddress?,DHCP,The DHCP server leases an address to the DHCP client.,Client,Client,Client,Server,Server,DHCP client broadcastsdiscover message,DHCP client broadcastsoffer message,DHCP client responds withrequest message,DHCP server seals the deal withacknowledgem

6、ent message,IP Datagram,Byte 1,Byte 2,Byte 3,Byte 4,Word 1 Word 2 Word 3 Word 4 Word 5 Word 6,Ver.,IHL,Service Type,Packet Length,Identification,Flag,Frag. Offset,Time to Live,Protocol,Header Checksum,Source Address,Destination Address,Options,Padding,Protocol Field,Transmission Control Protocol (TC

7、P),User Datagram Protocol (UDP),Internet Control Message Protocol,IPv6,ICMP for IPv6,EIGRP,Protocol,Protocol Field,6,17,1,58,88,41,Summary,The network layer provides a means for routing information from the source to a destination. IP is a standard that defines the manner in which the network layers

8、 of two hosts interact. ICMP is a protocol sent in response to errors in TCP/IP messages. ARP maps IP network addresses to the physical addresses.,Summary (Cont.),RARP maps physical addresses into IP addresses. DHCP automates the configuration of IP addresses on devices that use TCP/IP. IP transfers information through the network in the fo