System and Network Management

Transcription

1 - System and Network Management Network Management : ability to monitor, control and plan the resources and components of computer system and networks network management is a problem created by computer! Goal of network management : keep networks up and running Goal of Management -2 Keeping Network Running Maintaining Network performance Reducing the Cost of Ownership

2 -3 Architecture of Management Components : Manager and agent Manager : monitor and control the agents Agents: softwarte componentes residing in mangaed devices responds to requests from manager Network Management Protocol protocol used to communicated between Manager and agents -4 Manager Network Management Protocol agent agent agent

3 -5 Easy-to-implement network management tool fot TCP/IP suite of protocols : a collection of specification actual protocols definition of manage information other related components model -6 components manager, agent and protocol Manager Simple Network Management Protocol agent agent agent

4 agent -7 Software process that respons to protocol resides in networks equipments such as hub, router, bridges or workstaions Two basic roles monitoring controlling Hardware Components request agent Software Components response Components of agent -8 Protocol engine : processing request from managers receving request decoding servicing the request sending response Management Information Base (MIB) : collection of managed objects each object is a data variable standardized across system of a particular class agent Prortocol Engine request Management Information Base response

5 MIB objects -9 Each managed object has a unique identifier, called an MIB object identifier used for referencing an MIB object ALL standards agents are required to support a standard set of managed objects every MIB objects has an MIB definition that defines the managed object MIB definitions are created using Abstract Syntax Notation One (ASN.) ASN. is a machine-independence data description (initially developed for use in OSI) Only a subset of ASN. is used for Rules for writing MIB definitions using ASN. are defined in Structure of Management Information (SMI) protocol -0

6 operations - Get Request Get Next Request Get Response Set Request Trap Variable binding -2 Each variable binding consists of a variable called obkject identifier (OID) and associated value Object identifier Object value

7 MIB Tree ccitt 0 Root iso Joint-iso-ccitt 2-3 Structure for reference OID dod 6 org 3 internet directory mgmt 2 experimental 3 private 4 mib-2 enterprises vender object system interfaces 2 at 3 ip 4 icmp 5 tcp 6 udp 7 egp 8 transmission 0 snmp sysdesc ifnumber ASN. Notation -4 syscontact OBJECT-TYPE SYNTAX DisplayString (SIZE (0..255)) ACCESS read-write STATUS mandatory DESCRIPTION "The textual identification of the contact person for this managed node, together with information on how to contact this person." ::= { system 4 } syscontact OID = = iso.org.dod.internet.mgmt.mib-2.system.sycontact

8 Basic Encoding Rule -5 Each field is encoded by BER Tag Length Contents Tag : variable type Length : length of contents Contents : encoded data Encoding example -6 get request sequence of 39 bytes Version version community str E 6D bytes of community string = #! PDU type A0 B request of 25 bytes request ID D 3E id = error status error status =0 error index error index=0 variable binding 30 0E sequence of length 4 bytes 30 0C sequence of length of 2 bytes B object id of 8 bytes null of 0 bytes