计算机网络管理应用技术

community: “bearread” mib: system.sysContact (1.3.6.1.2.1.1.4) system.sysName (1.3.6.1.2.1.1.5) system.sysLocation (1.3.6.1.2.1.1.6)
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Installing SNMP Agent
Select the underlined item and click “next”
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Installing SNMP Agent
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Installing SNMP Agent
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Installing SNMP Agent
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21/tcp 23/tcp 25/tcp 110/tcp
User level process/services generally use port number value >= 1024
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Socket Types
Streaming Socket Datagram Socket Raw Socket
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Installing SNMP Agent
Installing SNMP Agent
(windowXP platform)
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Installing SNMP Agent
SNMP Manager & SNMP Agent
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Installing SNMP Agent
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Installing SNMP Agent
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Socket Programming: TCP Socket
Client Socket, Server Socket, New Socket
New Socket
Accept
Com mun icat
ing
Server Socket
Connect
Client Socket Remote IP Remote Port
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Socket Programming
Socket Programming
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Socket Programming: Socket
Sockets provide an interface for programming networks at the transport layer. Socket = IP Address + Port Network communication using Sockets is very much similar to performing file I/O Socket-based communication is programming language independent.
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TCP vs. UDP
UDP (User Datagram Protocol) A protocol that sends independent packets of data, called datagrams, from one computer to another Without guarantees about arrival Example Applications: Clock Server SNMP RTP
i ce Re ve
Datagram Socket
Local IP Local Port
Send
Datagram InetAddress Data
Local IP Local Port
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Socket Programming: An Example for Java UDP Socket
//Sender byte[ ] buffSend = new byte[1024]; String strHello = “Hello baby!”; buffSend = strHello.getBytes(); InetSocketAddress addr = new InetSocketAddress(“10.10.10.22", 1978); DatagramPacket pack = new DatagramPacket (buffSend, 0, buffSend.length, addr); DatagramSocket sockSend = new DatagramSocket(); sockSend.send(pack);
JRE is needed JDK1.5 released http://java.sun.com/j2se/1.5.0/download.jsp
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Mibbrowser Demo
Load/Unload Modules Explore MIB elements Get-request Get-next Set-request Get-bulk Show in Table Show in Line
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TCP vs. UDP
TCP (Transport Control Protocol) A connection-oriented protocol Provides a reliable flow of data between two computers Example applications: HTTP FTP Telnet
Installing SNMP Agent
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MIB files: c:\windows\system32
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Mibbrowser Demo
Mibbrowser Demo
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Mibbrowser Download
Download Web site： http://www.adventnet.com 2 components included: Snmp Disign Studio (30 days trial) Mibbrowser
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SNMP PDU in RFC1157
GetRequest-PDU GetNextRequest-PDU GetResponse-PDU SetRequest-PDU ::=[0]IMPLICIT PDU ::=[1]IMPLICIT PDU ::=[2]IMPLICIT PDU ::=[3]IMPLICIT PDU
Message::=SEQUENCE{ version INTEGER{version-1(0)}, community OCTET STRING, data ANY } PDU::=CHOICE{ get-request GetRequest-PDU, get-next-request GetNextRequest-PDU, get-response GetResponse-PDU, set-request SetRequest-PDU, trap Trap-PDU}
Port is represented by a positive (16-bit) integer value Some ports have been reserved to support common/well known services:
– – – –
ftp telnet smtp pop3
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Socket Programming: Port
The TCP and UDP protocols use ports to map incoming data to a particular process running on a computer.
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Socket Programming: Port
计算机网络管理应用技术
Computer Network Management Application Technology
张沪寅
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Course Contents
Installing SNMP Agent A simple SNMP demo: Mibbrowser Basic Network knowledge Socket Programming SNMP & Basic Encoding Rules Implementation of SNMP: low level socket Implementation of SNMP: using Java APIs CiscoWorks 2000 application
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An example of receiving packets
1. QQing 2. Web pages 3. Downloading 4. SNMP packets
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Basic Network Knowledge
Basic Network Knowledge
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Байду номын сангаас
Preparation: Basic Network Knowledge
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SNMP & Basic Encoding Rules
SNMP & Basic Encoding Rules
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SNMP PDU
SNMP PDU 0—Get; 1—Get-next; 2—Get-response; 3—Set-request; 4—Trap
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SNMP PDU in RFC1157
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SNMP PDU in RFC1157
VarBinList::=SEQUENCE OF VarBin VarBin::=SEQUENCE{ name ObjectName, value ObjectSyntax }
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SNMP PDU structure
sequence
version
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Implementation of SNMP: Low Level Socket
Implementation of SNMP:
Low Level Socket
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Datagram content
Example parameter: operate:get-request get-next set-request (0xA0) (0xA1) (0xA2)
TCP/IP vs. ISO/OSI IEEE802.3 vs. Ethernet II IP packet format TCP vs. UDP
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TCP/IP layers & Applications
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IEEE802.3 & Ethernet II
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IP Packet Format
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Socket Programming: An Example for Java UDP Socket
//Receiver DatagramSocket sockRcv = new DatagramSocket(1978); byte [] buffRcv = new byte[1024]; DatagramPacket pack = new DatagramPacket(buffRcv, buffRcv.length); sockRcv.receive(pack); // blocking process buffRcv properly
Listening ...
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Socket Programming: UDP Socket
Datagram Socket, Datagram Packet, InetAddress (Address + Port)
Datagram
d Sen
InetAddress Data
Recei ve
Datagram Socket
community
operatetype
ID
Error-status
Error-index
Sequence of
Sequence of
Sequence of
null
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Basic Encoding Rules
BER: type + length + value common type codes: 30—SEQUENCE 02—INTEGER 05—NULL 04—STRING 06—OBJECT IDENTIFIER
PDU::=SEQUENCE{ request-id INTEGER, error-status INTEGER{noError(0), tooBig(1), noSuchName(2), badValue(3), readOnly(4), genError(5)}, error-index INTEGER, variable-binding VarBinList}