Cisco Router Basics

Cisco IOS is a dedicated kernel that provides routing, switching, network interconnection, and remote communication capabilities. Most Cisco routers are running iOS, and more and more Cisco Catalyst switches are running it, including Catalyst2960 and Catalyst3560 series switches.

Some important aspects of the Cisco router iOS software are responsible for:

Run network protocols and provide functionality;

Transfer data between devices at high speed;

Improve security by controlling access and prohibiting unauthorized network use;

Provides scalability (in terms of network expansion) and redundancy, increasing the reliability of connected network resources

OSI : Open Systems Interconnection ISO: International Organization for Standardization

IOS : operation of Cisco switches and routers

OSI seven-layer model

TCP/IP four-layer model

TCP/IP five-layer model

TCP/IP 4 layer Model TCP/IP 5 layer Model OSI 7 layer model

TCP/IP composition of the agreement

Application layer HTTP, FTP, TFTP, SMTP, SNMP, DNS

Transport Layer TCP UDP

Network layer ICMP, IGMP, IP, ARP, RARP

protocol defined by the underlying network in the data link layer

Physical Layer

TCP/IP comparison of models with OSI models

Common

1 The OSI Reference Model and the TCP/IP Reference Model all use the concept of hierarchy,

2 ) can provide both link-oriented and non-linked communication service mechanisms;

Different points

1 The former is a seven-layer model, and the latter is a four-layer mechanism

2 different reliability requirements (the latter is higher)

3 The OSI model is designed prior to protocol development and is universal; TCP/IP is a protocol set and then a model, not for non-TCP/IP networks

4 The actual market application is different (the OSI model is only a theoretical model, and there is no mature product, and TCP/IP has become the "de facto International standard")

OSIseven-layer framework----Application Layer

application-level user interface
Represents the representation, security, and compression of layer data
Session layer establishment, management, abort session
Transmission layer reliability and unreliable transmission, error detection before transmission, flow control
Network layer for logical address addressing, error checking and other functions
Data Link Layer Group frame, hardware address addressing, error checking and other functions
transmission of bitstream between physical layer devices, physical interfaces, electrical properties, etc.


the correspondence between the equipment and the layer

application-tier computers
Transport Layer Firewall
Network layer Routers
Data Link Layer Switches
Physical layer Nic

WindowsARP commands in the system

arp-a: View the ARP cache table
arp-d: Clears the ARP cache
arp-s: IP MAC address binding IP with Mac

This article is from the "Wu-Dick" blog, please be sure to keep this source http://9827789.blog.51cto.com/9817789/1638397

Cisco Router Basics