Introduction to SNMPmohiqbal.staff.gunadarma.ac.id/Downloads/files/35177/mohiqbal+-+9+SNMP.pdf2....
68
Introduction to SNMP Dr. Mohammad Iqbal Thanks to : Yen-Cheng Chen http://www.im.tj.mcu.edu.tw/~ycchen/
Transcript of Introduction to SNMPmohiqbal.staff.gunadarma.ac.id/Downloads/files/35177/mohiqbal+-+9+SNMP.pdf2....
Introduction to SNMP
Dr. Mohammad Iqbal Thanks to : Yen-Cheng Chen
http://www.im.tj.mcu.edu.tw/~ycchen/
Contents
1. Basic Concepts
2. Management Information Base
3. Simple Network Management Protocol
4. SNMP Application Examples4. SNMP Application Examples
5. Reference
Appendix: ASN.1 Concept
1. Basic Concepts
FDDI
ManagementStation
ManagementStation
....
...
PC UNIX
NMNMNMNM
3
InternetInternet
RMONDevice
UNIX....
UNIX PC
Firewall/ Router ....
...
PollingPolling NotificationNotification
PC
SNMP Standard
Internet SNMPv1, SNMPv2, SNMPv3
ISO/ITU-T X.700 Series: CMIP/S (Common Management Information Protocol /
4
CMIP/S (Common Management Information Protocol / Service)
ITU-T M.3000 Series: TMN (Telecommunication Management Networks)
SNMP Concepts
SNMP: Simple Network Management Protocol
De facto standards of network management for TCP/IP networks (Internet)networks (Internet)
IAB recommends all IP & TCP implementations should be network manageable.
That is, all TCP/IP network devices should support SNMP.
IAB: Internet Activities Board
SNMP Architectural Model
Key Components One or more Management Stations
• Perform management applications, i.e, Monitor & Control.
Multiple Network Elements Multiple Network Elements• hosts, routers, gateways, ..., which each contain an Agent.
Network Management Protocol• Exchange network management information.
SNMP Architectural Model (cont.)
SNMP SNMPSNMP
Manager Agent Agent
ManagementStation Host Router
Network Elements (NEs)
Network
Network
網路介面
SNMP
UDP
IP
網路介面
SNMP
UDP
IP
網路介面
SNMP
UDP
IP
. . .Network
ManagementProtocol
SNMP
Management Components
Manager
Agent
Network Management Protocol
8
Network Management Protocol
Management Information Base (MIB)
Management Components
Management Station (Manager) Network management applications. Provide an interface which the human network manager can
monitor and control the network.
Agent
9
Agent Network devices should be equipped with agent software so
that they can be managed from a management station. Responds to requests for information from managers. Responds to requests for actions from managers. May asynchronously provide managers with important but
unsolicited information.
Management Components (cont.)
Network Management Protocol
Communication protocol between managers and agents
NM protocol provides a standard way to exchange
management information between managers and agents.
10
management information between managers and agents.
Management Information Base (MIB)
A collection of Managed Objects.
The resources to be managed are represented as objects,
called Managed Objects (MOs).
Management Information Base (MIB)
Each resource to be managed is represented by an object, called managed object (MO).
The MIB is a structured collection of MOs.
Essentially, each MO is a data AgentAgent
Managed Resources
MIBMIB Essentially, each MO is a data
variable. Each agent in an NE maintains an
MIB.
Monitor: by reading the values of MOs in the MIB.
Control: by modifying the values of MOs in the MIB.
網路介面
SNMP
UDP
IP
AgentAgent
NE: Network Element
SNMP Services
Four Services Get, Set, GetNext, Trap
Five SNMP PDUs GetRequest, SetRequest, GetNextRequest, GetResponse, Trap
Manager Agent(s)
Get, Set, GetNext Request
Get Response
Trap
PDU: Protocol Data Unit
SNMP Services
Get Request
Get ResponseManager Agent
GetNext Request
Get ResponseManager Agent
Get
GetNext
Get
GetNext
13
Get ResponseManager Agent
Set Request
Get ResponseManager Agent
Trap RequestManager Agent
GetNext
Set
Trap
GetNext
Set
Trap
SNMP Services (cont.)
Get Request: Retrieve the values of objects in the MIB of an agent.
Get-Next Request: Retrieve the values of the next objects in the MIB of an agent. Retrieve the values of the next objects in the MIB of an agent.
Set Request: Update the values of objects in the MIB of an agent.
Trap Request Report extraordinary events to the manager.
Get-Next Request
MIB Tree :In SNMP, Only leaf objects have values.
＊
:Non-Leaf Object
:Leaf Object1 2 3
4 5 6
Default UDP Ports for SNMP
SNMP
Manager
ManagementStation
Network Elements (NEs)
SNMP
Agent
網路介面
SNMP
UDP
IP
網路介面
SNMP
UDP
IP
162 Any 161 Any
SNMP Standards
SNMP Protocol (Std 15) RFC1157: Simple Network Management Protocol.
Structure of Management Information (SMI) (Std 16) RFC1155: Structure and Identification of Management
Information for TCP/IP-based Internets.Information for TCP/IP-based Internets.
RFC1212: Concise MIB Definitions.
MIB-II (Std 17) RFC1213: Management Information Base for Network
Management of TCP/IP-based Internets: MIB-II.
http://www.isi.edu/rfc-editor/rfc.html
2. Management Information Base
Structure of Management Information (SMI) Set of rules on how managed objects should be defined.
Objects are defined using Abstract Syntax Notation One ASN.1 (ITU-T X.208 / ISO 8824)
MIB MIB The collection of all defined objects
Contains hierarchically organized variables corresponding to managed objects.
MIB-II, RMON MIB, Bridge MIB, Repeater MIB, X.25 MIB, FDDI MIB, Token Ring MIB, ...
Object Identifier Object Identifier (OID):
Global identifier for a particular object type.
An OID consists of a sequence of integers, which specify the position of the object in the global object identifier tree.
root
ccitt iso joint-iso-ccitt0 1 2
0 3
directory
std regauthority
memberbody
org0
1 2 3
dod
internet
6
1
12 3 4
mgmt experimental private
MIB II
system1
interface2
at3
IP4
ICMP5
TCP6
UDP7
EGP8
Trans.10
SNMP11
1 1enterprises
1.3.6.1.2.1.2 1.3.6.1.4.1
1.3.6.1.2.1
MIB II
interface
enterprises
Private MIB Registration
Companies can register their private MIB extensions in the global MIB tree by contacting the Internet Assigned Numbers Authority (IANA).
20
Authority (IANA).
http://www.iana.org/http://www.iana.org/
Currently assigned enterprise subtrees
ftp://ftp.isi.edu/inftp://ftp.isi.edu/in--notes/iana/assignments/enterprisenotes/iana/assignments/enterprise--numbersnumbers
SMI (RFC1155)RFC1155-SMI DEFINITIONS ::= BEGINEXPORTS -- EVERYTHING
internet, directory, mgmt, experimental, private,enterprises, OBJECT-TYPE, ObjectName, ObjectSyntax, SimpleSyntax,ApplicationSyntax, NetworkAddress, IpAddress, ApplicationSyntax, NetworkAddress, IpAddress, Counter, Gauge, TimeTicks, Opaque;
internet OBJECT IDENTIFIER ::= { iso org(3) dod(6) 1 }directory OBJECT IDENTIFIER ::= { internet 1 }mgmt OBJECT IDENTIFIER ::= { internet 2 }experimental OBJECT IDENTIFIER ::= { internet 3 }private OBJECT IDENTIFIER ::= { internet 4 }enterprises OBJECT IDENTIFIER ::= { private 1 }
SMI (cont.)OBJECT-TYPE MACRO ::=
BEGINTYPE NOTATION ::=
"SYNTAX" type (TYPE ObjectSyntax)"ACCESS" Access"STATUS" Status
VALUE NOTATION ::= value (VALUE ObjectName)
ASN.1 Macro
VALUE NOTATION ::= value (VALUE ObjectName)Access ::= "read-only"
| "read-write"| "write-only"| "not-accessible"
Status ::= "mandatory" | "optional"| "obsolete"
END
ObjectName ::= OBJECT IDENTIFIER
OBJECT-TYPE Example
sysDesc OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
ACCESS read-only
23
ACCESS read-only
STATUS mandary
::= { system 1}
ObjectName ::= OBJECT IDENTIFIER
ObjectSyntax ::=CHOICE {
simple SimpleSyntax,application-wide
ApplicationSyntax}
SimpleSyntax ::=CHOICE {
number INTEGER,
NetworkAddress ::=CHOICE {
internet IpAddress}IpAddress ::=
[APPLICATION 0]IMPLICIT OCTET STRING (SIZE (4))
Counter ::=[APPLICATION 1]IMPLICIT INTEGER (0..4294967295)
Gauge ::=
SMI (cont.)
number INTEGER,string OCTET STRING,object OBJECT IDENTIFIER,empty NULL} }
ApplicationSyntax ::=CHOICE {
address NetworkAddress,counter Counter,gauge Gauge,ticks TimeTicks,arbitrary Opaque}
Gauge ::=[APPLICATION 2]IMPLICIT INTEGER (0..4294967295)
TimeTicks ::=[APPLICATION 3]IMPLICIT INTEGER (0..4294967295)
Opaque ::=[APPLICATION 4] IMPLICIT OCTET STRING
END
Object Syntax Summary
Simple Syntax Integer
Octet String
Object Identifier
Application Syntax Network Address
Counter
Gauge
25
Object Identifier
Null
Gauge
Time Ticks
Opaque
Concise MIB Definition (RFC 1212)
OBJECT-TYPE MACRO ::=
BEGIN
TYPE NOTATION ::=
"SYNTAX" type(ObjectSyntax)
"ACCESS" Access
"STATUS" Status
DescrPart
ReferPart
DescrPart ::=
"DESCRIPTION" value (description DisplayString)
| empty
ReferPart ::=
"REFERENCE" value (reference DisplayString)
| empty
IndexPart ::=
"INDEX" "{" IndexTypes "}" | emptyReferPart
IndexPart
DefValPart
VALUE NOTATION ::=
value (VALUE ObjectName)
"INDEX" "{" IndexTypes "}" | empty
IndexTypes ::=
IndexType | IndexTypes "," IndexType
IndexType ::=
value (indexobject ObjectName) | type (indextype)
DefValPart ::=
"DEFVAL" "{" value (defvalue ObjectSyntax) "}"
| empty
END
Examples: MIB II (RFC 1213)mib-2 OBJECT IDENTIFIER ::= { mgmt 1 }system OBJECT IDENTIFIER ::= { mib-2 1 }interfaces OBJECT IDENTIFIER ::= { mib-2 2 }at OBJECT IDENTIFIER ::= { mib-2 3 }ip OBJECT IDENTIFIER ::= { mib-2 4 }icmp OBJECT IDENTIFIER ::= { mib-2 5 }
tcp OBJECT IDENTIFIER ::= { mib-2 6 }udp OBJECT IDENTIFIER ::= { mib-2 7 }egp OBJECT IDENTIFIER ::= { mib-2 8 }-- cmot OBJECT IDENTIFIER ::= { mib-2 9 }
transmission OBJECT IDENTIFIER ::= { mib-2 10 }snmp OBJECT IDENTIFIER ::= { mib-2 11 }
ifEntry OBJECT-TYPEifTable OBJECT-TYPESYNTAX IfEntryACCESS not-accessibleSTATUS mandatoryDESCRIPTION
"An interface entry containing objects at the subnetwork layer and below for a particular interface."
INDEX { ifIndex }::= { ifTable 1 }
SYNTAX SEQUENCE OF IfEntryACCESS not-accessibleSTATUS mandatory
DESCRIPTION"A list of interface entries. The number of entries is givenby the value of ifNumber."
::= { interfaces 2 }
Identification of Managed Objects
Use Object Identifier (OID)
OID = Object Type OID . Instance Identifier
Object Type OID:
28
Object Type OID: Each Object type has a unique OID
Instance Identifier: Identify instances of object type
E.g .mib-2.interface.ifTable.ifEntry.ifDescr.2
Two Kinds of Managed Objects
Type-Specific Objects: sysDescr OBJECT-TYPE
SYNTAX DisplayString (SIZE(0..255))
::= {system 1}
OID: mib-2.system.1.0
29
OID: mib-2.system.1.0
Columnar Objects OID:
mib-2.interface.ifTable.ifEntry.ifDescr.2mib-2.interface.ifTable.ifEntry.ifDescr.6mib-2.interface.ifTable.ifEntry.ifType.2mib-2.interface.ifTable.ifEntry.ifType.6
Columnar Objects
ifTable OBJECT-TYPESYNTAX SEQUENCE OF IfEntry…::= { interface 2 }
IfEntry ::= SEQUENCE {ifIndex INTEGER,ifDescr DisplayString,ifType INTEGER,…
30
…}
ifEntry OBJECT-TYPESYNTAX IfEntry…INDEX {ifIndex }::= { ifTable 1}
ifDescr OBJECT-TYPESYNTAX DisplayString (SIZE(0..255))ACCESS read-onlySTATUS madatory
...::= {ifEntry 2}
Columnar Objects
ifIndex ifDescr ifType . . .
1 le0 6 . . .
6 llc0 1 . . .
.ifTable.ifEntry.1 (1.3.6.1.2.1.2.2.1.1)
.ifTable.ifEntry.2 (1.3.6.1.2.1.2.2.1.2)
.ifTable.ifEntry.3 (1.3.6.1.2.1.2.2.1.3)
31
6 llc0 1 . . .
7 lo0 24 . . .
9 le1 6 . . .
1.3.6.1.2.1.2.2.1.3.71.3.6.1.2.1.2.2.1.2.6
Index in MIB II ifEntry {ifIndex} atEntry {atNetIfIndex, atNetAddress}
ipAddrEntry {ipAdEntAddr }
ipRouteEntry {ipRouteDest}
ipNetToMediaEntry {ipNetToMediaIfIndex,
32
ipNetToMediaEntry {ipNetToMediaIfIndex,
ipNetToMediaNetAddress}
tcpConnEntry
{tcpConnLocalAddress, tcpConnLocalPort,
tcpConnRemoteAddress, tcpConnRemotePort}
udpEntry {udpLocalAddress, udpLocalPort}
egpNeighEntry {egpNeighAddr}
Index Example
To get the state of the TCP connection:10.144.18.118:1200 ===> 10.144.14.40:1600
Use snmp_get_req. to get the “tcpConnState”
33
Use snmp_get_req. to get the “tcpConnState” of the tcpConnTable in MIB II.
tcpConnState ==> .1.3.6.1.2.1.6.13.1.1
.1.3.6.1.2.1.6.13.1.1.10.144.18.118.1200.10.144.14.40.1600
MIB II
System Group Provide general information about the managed system.
Interfaces Group Contains generic information about the physical interfaces.
Address-Translation Group Contains information about the mapping between network addresses and Contains information about the mapping between network addresses and
physical addresses for each physical interface.
IP Group Contains information about the implementation and operation of IP at the
managed system.
ICMP Group Contains information about the implementation and operation of ICMP at the
managed system.
MIB-II (cont.) TCP Group
Contains information about the implementation and operation of TCP at the managed system.
UDP Group Contains information about the implementation and operation of UDP at the
managed system.
EGP Group Contains information about the implementation and operation of EGP at the Contains information about the implementation and operation of EGP at the
managed system.
Transmission Group Provides details about the underlying transmission media for each interface.
SNMP Group Provides the statistics of SNMP operations at the managed system.
IETF MIBs
1213 MIB-II
1316 Character Stream
1317 RS-232-like Hardware
1471 PPP 1471 PPP
1513 RMON for Token Ring
1757 RMON
2021 RMON-II
.....
3. SNMP
SNMP Message Version Identifier
Community Name
Protocol Data Unit
Message ::=SEQUENCE {
version INTEGER {version-1(0)},community OCTET STRING,data ANY
}
The length of SNMP messages should not exceed 484 octets.
Version Community SNMP PDU
SNMP Authentication
Community
Relationship between an Agent and Managers.
Community Name
Used to validate the SNMP messages.
SNMP Password.
Default ‘Get’ community name: “public”.
Authentication Failure
Agent sends “Authentication Failure Trap” to Manager.
SNMP PDUPDU ::= SEQUENCE {
request-id INTEGER,error-status INTEGER {
noError(0),tooBig(1),noSuchName(2),badValue(3),readOnly(4)
GetRquest :GetNextRequest :
GetResponse :
[0] PDU[1] PDU[2] PDU
Five SNMP PDUs:
readOnly(4)genErr(5)},
error-index INTEGER,variable-bindings
SEQUENCE OF {name ObjectName,value ObjectSyntax
}}
GetResponse :SetRequest :
Trap :
[2] PDU[3] PDU[4] Trap-PDU
PDU: Protocol Data Unit
SNMP PDU (cont.)
PDU type request-id 0 0 variable-bindings
GetRequest, GetNextRequest, SetRequest
GetResponse
PDU type request-id error-status error-index variable-bindings
GetResponse
variable-bindings
name value name value name value. . .
Trap-PDUTrap-PDU ::= [4]
IMPLICIT SEQUENCE {enterprise OBJECT IDENTIFIER,agent-addr NetworkAddress,
generic-trap INTEGER {coldStart(0),warmStart(1),linkDown(2),linkUp(3),
Enterprise:Type of Object generating trap.
Agent Address:Address of object generating trap.
Generic Trap:Generic trap type.
Specific Trap:Enterprise specific trap.
linkUp(3),authenticationFailure(4),egpNeighborLoss(5),enterpriseSpecific(6)},
specific-trap INTEGER,time-stamp TimeTicks,variable-bindings VarBindList
}
Enterprise specific trap.
Time Stamp:Time elapsed between the last initialization of the network entity andthe generation of the trap.
Variable Bindings“Interesting” information
PDU type enterprise agent-addr generic-trap variable-bindingsspecific-traptime-stamp
How does a Manager do?
Translates Internal Data to
ASN.1 Format
Sends RequestPDU to Agent
NMApplication
Agent
Translates ASN.1Package to Internal
Data Format
Received ResponsePDU from Agent
NMApplication
Agent
Manager
How does an Agent do?
Received SNMP Request PDU from Manager
Translates ASN.1Structure to
Internal Data
Maps MIB Variables to
Internal Variables
FromManager
Sends SNMP Response PDU
to Manager
Translates ResponsePDU to ASN.1
Format
Implement SNMP Request to Set orGet MIB Value
ToManager
Agent
Main Loop of Agent Agent waits for an incoming datagram in Port 161
Reads the datagram from UDP and notes the transport address of the sending entity.
Increments the QUANTUM to keep track of the logical request-id being processed by agent
De-serializes the datagram into an ASN.1 structure. If error De-serializes the datagram into an ASN.1 structure. If error occurs, log error and discard packet.
The ASN.1 structure is translated into SNMP message. If error occurs, log error and discard packet.
Check on VERSION-NUMBER field. If error occurs, log error and discard packet.
Main Loop of Agent (cont.)
Community name is looked up.
If community is unknown to agent, agent send AUTHENTICATION trap to Manager station in Port 162; log error and discard packet.
Agent loops through list of variables in the request.
If no prototype is found, return a GET-RESPONE with error noSuchName and discard package.
Once prototype is fund, operation is checked against community profile. If mismatch occurs, return get-respone with error noSuchName or readOnly and discard package.
Otherwise, agent invokes access routine to perform the desired operation.
What's New in SNMPv2
No more Trap PDU, 3 New PDUs:
getBulkReq, InformReq, SNMPv2-Trap
Added Security
18 Error Status Values 18 Error Status Values
SNMPv2 SMI / SNMPv2 MIB
M-to-M Communications
Table Operations
...
4. SNMP Application Examples SNMP Commands
snmpget [options] node variable [...]• query a node using SNMP Get request
snmpnext [options] node variable [...]• query a node using SNMP GetNext request
snmpwalk [options] node variable snmpwalk [options] node variable • query a node repeatedly using SNMP GetNext/GetBulk requests
snmptrap [-d] [-p port] [-c community] node enterprise agent-addr generic-trap specific-trap time-stamp variable type value [variable type value...]
• issue an SNMP Version 1 Trap
options:[-d] [-t timeout] [-r retries] [-p port] [-c community] [-v version]
Example for snmpget>>snmpget -d 10.144.18.118 .1.3.6.1.2.1.1.1.0Transmitted 41 bytes to camry (10.144.18.118) port 161:
Initial Timeout: 0.80 seconds
0: 30 27 02 01 00 04 06 70 75 62 6c 69 63 a0 1a 02 0'.....public...
16: 02 18 bc 02 01 00 02 01 00 30 0e 30 0c 06 08 2b .........0.0...+
32: 06 01 02 01 01 01 00 05 00 -- -- -- -- -- -- -- ................
0: SNMP MESSAGE (0x30): 39 bytes
2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)
5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public"
13: GET-REQUEST-PDU (0xa0): 26 bytes
15: INTEGER REQUEST-ID (0x2) 2 bytes: 6332
19: INTEGER ERROR-STATUS (0x2) 1 bytes: noError(0)
22: INTEGER ERROR-INDEX (0x2) 1 bytes: 0
25: SEQUENCE VARBIND-LIST (0x30): 14 bytes
27: SEQUENCE VARBIND (0x30): 12 bytes
29: OBJ-ID (0x6) 8 bytes: .1.3.6.1.2.1.1.1.0
39: NULL (0x5) 0 bytes
Example for snmpget (cont.)Received 69 bytes from camry (10.144.18.118) port 161:
0: 30 43 02 01 00 04 06 70 75 62 6c 69 63 a2 36 02 0C.....public.6.16: 02 18 bc 02 01 00 02 01 00 30 2a 30 28 06 08 2b .........0*0(..+32: 06 01 02 01 01 01 00 04 1c 53 75 6e 20 53 4e 4d .........Sun SNM48: 50 20 41 67 65 6e 74 2c 20 53 55 4e 57 2c 55 6c P Agent, SUNW,Ul64: 74 72 61 2d 31 -- -- -- -- -- -- -- -- -- -- -- tra-1...........0: SNMP MESSAGE (0x30): 67 bytes2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public"
13: RESPONSE-PDU (0xa2): 54 bytes15: INTEGER REQUEST-ID (0x2) 2 bytes: 633219: INTEGER ERROR-STATUS (0x2) 1 bytes: noError(0)22: INTEGER ERROR-INDEX (0x2) 1 bytes: 025: SEQUENCE VARBIND-LIST (0x30): 42 bytes27: SEQUENCE VARBIND (0x30): 40 bytes29: OBJ-ID (0x6) 8 bytes: .1.3.6.1.2.1.1.1.039: OCTET-STR (0x4) 28 bytes: "Sun SNMP Agent, SUNW,Ultra-1"
system.sysDescr.0 : DISPLAY STRING- (ascii): Sun SNMP Agent, SUNW,Ultra-1
Example of snmpwalk
snmpwalk 10.144.18.118 .1.3.6.1.2.1.1system.sysDescr.0 : DISPLAY STRING- (ascii): Sun SNMP Agent, SUNW,Ultra-1
system.sysObjectID.0 : OBJECT
IDENTIFIER: .iso.org.dod.internet.private.enterprises.42.2.1.1
system.sysUpTime.0 : Timeticks: (198219958) 22 days, 22:36:39.58system.sysUpTime.0 : Timeticks: (198219958) 22 days, 22:36:39.58
system.sysContact.0 : DISPLAY STRING- (ascii): [email protected]
system.sysName.0 : DISPLAY STRING- (ascii): camry
system.sysLocation.0 : DISPLAY STRING- (ascii): Information Technology
Laboratory 3F
system.sysServices.0 : INTEGER: 72 (01001000)B
Example of snmptrap snmptrap -d manager .1.3.6.1.4.1.612.1.1 10.144.18.116 6 99999
0 .1.3.6.1.1 octetstringascii "Trap test"Transmitted 64 bytes to manager (10.144.18.100) port 162:
0: 30 3e 02 01 00 04 06 70 75 62 6c 69 63 a4 31 06 0>.....public.1.16: 09 2b 06 01 04 01 84 64 01 01 40 04 0a 90 12 74 [email protected]: 02 01 06 02 03 01 86 9f 43 01 00 30 13 30 11 06 ........C..0.0..48: 04 2b 06 01 01 04 09 54 72 61 70 20 74 65 73 74 .+.....Trap test0: SNMP MESSAGE (0x30): 62 bytes2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public"2: INTEGER VERSION (0x2) 1 bytes: 0 (SNMPv1)5: OCTET-STR COMMUNITY (0x4) 6 bytes: "public"
13: V1-TRAP-PDU (0xa4): 49 bytes15: OBJ-ID ENTERPRISE (0x6) 9 bytes: .1.3.6.1.4.1.612.1.126: IPADDRESS AGENT-ADDR (0x40) 4 bytes: 10.144.18.116 (manager2)32: INTEGER GENERIC-TRAP (0x2) 1 bytes: 635: INTEGER SPECIFIC-TRAP (0x2) 3 bytes: 9999940: TIMETICKS TIME-STAMP (0x43) 1 bytes: 0 (0x0)43: SEQUENCE VARBIND-LIST (0x30): 19 bytes45: SEQUENCE VARBIND (0x30): 17 bytes47: OBJ-ID (0x6) 4 bytes: .1.3.6.1.153: OCTET-STR (0x4) 9 bytes: "Trap test"
Get System Information
Get “System Group” of MIB II
Use get_request or get_next_requestsysDescr .1.3.6.1.2.1.1.1.0
sysObjectID .1.3.6.1.2.1.1.2.0
52
sysObjectID .1.3.6.1.2.1.1.2.0
sysUptime .1.3.6.1.2.1.1.3.0
sysContact .1.3.6.1.2.1.1.4.0
sysName .1.3.6.1.2.1.1.5.0
sysLocation .1.3.6.1.2.1.1.6.0
Get Interface Information
Get “Interface Group” of MIB II
Repeatedly Use “get_next_request”
Note: We don’t know the ifIndex values in
53
ifTable.First get the next object of .ifTable.ifEntry.0
Then repeatedly “get_next”
Until the whole subtree is visited.
54
Traffic Monitoring
Get “ifInOctets” and “ifOutOctets” of MIB II Interface Group
t1: C1 t2: C2
55
(C2 - C1 ) 8
(t2 - t1) Bandwidth 100%Utilization (%) =
56
6. Reference
The Simple Book, marshall T.Rose, Prentice-Hall Inc.
SNMP, SNMPv2 and RMON: The Practical Guide to Network Management, Willeam Stallings
SMI; http://ds.internic.net/rfc/rfc1155.txt
Concise MIB Format; http://ds.internic.net/rfc/rfc1212.txt Concise MIB Format; http://ds.internic.net/rfc/rfc1212.txt
SNMP; http://ds.internic.net/rfc/rfc1157.txt
MIB II; http://ds.internic.net/rfc/rfc1213.txt
Trap Format; http://ds.internic.net/rfc/rfc1215.txt
ASN.1 and BER; ITU-T X.208, X.209
Development of SNMP Standards
SNMPv2 SNMPv3
RMON I
58
RMON II
SNMPv3
An Architecture for Describing Internet Management Frameworks
Local Processing Model for version 3 of the Simple Network Management Protocol (SNMPv3)
Message Processing and Control Model for version 3 of the Simple Network Management Protocol (SNMP)
59
of the Simple Network Management Protocol (SNMP)
User-based Security Model for version 3 of the Simple Network Management Protocol (SNMPv3)
View-based Access Control Model (VACM) for version 3 of the Simple Network Management Protocol (SNMP)
User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)
RMON I & II
APPLICATION Presentation
Session RMON2
RMON 2
Transport
60
Network Data Link
(MAC)RMON
1
Ethernet
TokenRing
FDDI
Frame Relay,HDLC, PPD,SDLL, X.25,
CIRPPhysical
V-series
T1 E1G703
Appendix: ASN.1 Concepts
ASN.1: Abstract Syntax Notation One
ISO/ITU-T Standards: ISO 8824/ITU-T X.208
Abstract Syntax: Use a syntax to define data/data structure independent of Use a syntax to define data/data structure independent of
machine-oriented structures and restrictions.
Use in SNMP Define SNMP PDU format
Define management information (MIB)
ASN.1 Reserved Words
All reserved words MUST be upper case BOOLEAN INTEGER BIT STRING
OCTET NULL OF SEQUENCE
SET IMPLICIT CHOICE ANY
EVTERNAL OBJECT END IDENTIFIER
OPTIONAL DEFAULT TRUE COMPONTS
FALSE BEGIN
What are defined using ASN.1
Types: data structures
e.g. Counter, Gauge, IpAddess, ...
Values: instances (variables) of a type
63
instances (variables) of a type
e.g. sysContact, ifTable, ifSpeed, ...
Macros: used to change the actual grammar of ASN.1
e.g. OBJECT-TYPE, ACCESS, ...
Modules
Module: A collection of ASN.1 descriptions
Module Structure<module name> DEFINITION ::= BEGIN
<module body>
END
ExampleEmptyModule
DEFINITION ::= BEGIN
END
Tags and Types
Tags Every type defined with ASN.1 is assigned a tag
Tag = Class + Number
• Class: (Bit 8,7 in BER tag) – Universal 0 0
– Application 0 1
– Context-specific 1 0
– Private 1 1
• Number: non-negative Integer
BER: Basic Encoding Rules
Tags and Types (cont.) Universal Tag ASN.1 Type
1 BOOLEAN
2 INTEGER
3 BIT STRING
4 OCTET STRING
5 NULL
6 OBJECT IDENTIFIER
Universal Tag ASN.1 Type
18 NumericString
19 PrintableString
20 TeletexString
21 VediotextString
22 IA5String6 OBJECT IDENTIFIER
7 ObjectDescriptor
8 EXTERNAL
9 REAL
10 ENUMERATED
12-15 Reserved
16 SEQUENCE, SEQUENCE OF
17 SET, SET OF
23 UTCTime
24 GeneralizeTime
25 GraphicString
26 VisssibleString
27 GeneralString
28 CharacterString
29-... Reserved
Values in ASN.1
General format of a value assignment <valuereference> <type> ::= <value>
Examples: BOOLEAN BOOLEAN
• Married ::= BOOLEAN
• currentStatus Married ::= FALSE
INTEGER• Color ::= INTEGER{red (0), blue (1), yellow (2)}
• defaultColor Color ::= 1
• defaultColor Color ::= blue
Basic Encode Rules BER
A transfer syntax notation
ISO/ITU-T Standards: ISO 8825/ITU-T X.209
Values from any abstract syntax defined using ASN.1 can be encoded with BERbe encoded with BER
BER uses Tag, Length, Value (TLV) encoding• Tag: “identifier”, Length: length of content, Value: “contents”
Each value may itself be made up of one or more TLV-encoded values
T TL TL V V
V
L
![Smi cop8[1]](https://static.fdocuments.in/doc/165x107/54959009b47959146b8b4599/smi-cop81.jpg)
