2. CHAPTER 9: NETWORK MANAGEMENT Management Information Base Management Information Base Abstract Syntax Notation Abstract Syntax Notation Simple Network Management Protocol Simple Network Management Protocol

3. NETWORK MANAGEMENT Page 202Chapter 9CS 447 The manager endstation (running client software) contacts each agent (running server software), querying for management data.

4. STANDARD MANAGEMENT INFORMATION BASE VARIABLES Page 203Chapter 9CS 447 MIB Variable CategoryCategory MeaningMeaning sysUpTimesysUpTime Operating System Time since last reboot ifNumberifNumber Network Interfaces Number of network interfaces ifMtuifMtu Network Interfaces Max. xfer unit for particular interface ipDefaultTTLipDefaultTTLIPIP Value IP uses in time-to-live field ipInReceivesipInReceivesIPIP Number of datagrams received ipForwDatagramsipForwDatagramsIPIP Number of datagrams forwarded ipOutNoRoutesipOutNoRoutesIPIP Number of routing failures ipReasmOKsipReasmOKsIPIP Number of datagrams reassembled ipFragOKsipFragOKsIPIP Number of datagrams fragmented ipRoutingTableipRoutingTableIPIP IP Routing Table icmpInEchosicmpInEchosICMPICMP Number of ICMP Echo Requests received tcpRtoMintcpRtoMinTCPTCP Minimum retransmission time TCP allows tcpMaxConntcpMaxConnTCPTCP Maximum TCP connections allowed tcpInSegstcpInSegsTCPTCP Number of segments TCP has received udpInDatagramsudpInDatagramsUDPUDP Number of UDP datagrams received egpInMsgsegpInMsgsEGPEGP Number of EGP messages received

5. STRUCTURE OF MIB OBJECT NAMES Page 204Chapter 9CS 447 system1interfaces2 addr. trans. 3ip4icmp5udp7tcp6egp8 mib1 directory1mgmt2experimental3private4 internet1 dod6 org3 iso1itu2 joint iso/itu 3 The variables used in TCP- based management protocols use the Management Information Base standard, which uses the hierarchical namespace that is partially outlined at right. unnamed Example: The MIB object name 1.3.6.1.2.1.37.1.5.1.8 corresponds to ATM’s QoS iso(1). org(3). dod(6). internet(1). mgmt(2). mib-2(1). atmMIB(37). atmMIBObjects(1). atmTrafficDescrParamTable(5). atmTrafficDescrParamEntry(1)

6. ABSTRACT SYNTAX NOTATION (ASN.1) Page 205Chapter 9CS 447 The object definition language adopted by the OSI, ASN.1 encodes data in a standard fashion, as a three-field structure: Identifier Tag Length of Data Data For example, the integer 100 is represented as: 020164 Type 2: Integer IntegerLength: 1 Byte Length: Value in Hexadecimal Hexadecimal Another example, the ASCII string “OW!” is represented as: 04034F 57 21 Type 4: String StringLength: 3 Bytes Length: Value in Hexadecimal Hexadecimal

7. SIMPLE NETWORK MANAGEMENT PROTOCOL Page 206Chapter 9CS 447 SNMP uses ASN.1 to format communications between managers and agents, as shown at right. 0406 Type 4: String StringLength: 6 Bytes Length: Value:“public”Value:“public” 70 75 62 6C 69 630201 Type 2: Integer IntegerLength: 1 Byte Length: Version:0Version:0 003029 Type 48: Sequence SequenceLength: 41 Bytes Length: A01C getreq.getreq. Length: 28 Bytes Length: 0204 Type 2: Integer IntegerLength: 4 Bytes Length: Request ID 05 AE 56 020201 Type 2: Integer IntegerLength: 1 Byte Length: StatusStatus 000201 Type 2: Integer IntegerLength: 1 Byte Length: ErrorIndexErrorIndex 00 300C Type 48: Sequence SequenceLength: 12 Bytes Length: 0608 ObjectIDObjectIDLength: 8 Bytes Length: Data Item sysDescr (numeric object identifier 43. 6. 1. 2. 1. 1. 1. 0 2B 06 01 02 01 01 01 00 300E Type 48: Sequence SequenceLength: 14 Bytes Length: 0500 NullNull Length: 0 Bytes Length: This particular SNMP message is a request for the sysDescr data item.