Transcript Business Data Communications 4e

Chapter 19:
Network Management
Business Data Communications,
4e
Network Management
Requirements
 Fault Management
 Accounting Management
 Configuration and Name Management
 Performance Management
 Security Management
Business Data Communications,
4e
2
Fault Management
 A fault is an abnormal condition that
requires management attention (or
action) to repair
 Fault is usually indicated by failure to
operate correctly or by excessive errors
 Users expect quick and reliable
resolution
Business Data Communications,
4e
3
Accounting Management
 Reasons for accounting management:




Internal chargebacks on network use
User(s) may be abusing access privileges and
burdening the network at the expense of other
users
Users may be making inefficient use of the
network
The network manager is in a better position to
plan for network growth if user activity is known in
sufficient detail.
Business Data Communications,
4e
4
Configuration Management
 Concerned with:


initializing a network and grace-fully
shutting down part or all of the network
maintaining, adding, and updating the
relationships among components and the
status of components themselves during
network operation
Business Data Communications,
4e
5
Performance Management
 Issues of concern to the network manager include:





What is the level of capacity utilization?
Is there excessive traffic?
Has throughput been reduced to unacceptable levels?
Are there bottlenecks?
Is response time increasing?
 Network managers need performance statistics to
help them plan, manage, and maintain large
networks
Business Data Communications,
4e
6
Security Management
 Concerned with




generating, distributing, and storing
encryption keys
monitoring and controlling access to
networks
access to all or part of the network
management information
collection, storage, and examination of
audit records and security logs
Business Data Communications,
4e
7
Network Management
Systems
 Collection of tools for network monitoring and
control, integrated in these ways:


A single user-friendly operator interface for
performing most or all network management tasks
A minimal amount of separate equipment
 consists of incremental hardware and
software additions implemented among
existing network components
Business Data Communications,
4e
8
Network Management System Architecture
Business Data Communications,
4e
9
Components of the NMS
 All nodes run the Network Management
Entity (NME) software
 Network control host or manager runs
the Network Management Application
(NMA)
 Other nodes are considered agents
Business Data Communications,
4e
10
Network Monitoring Systems
Business Data Communications,
4e
11
Simple Network Management
Protocol (SNMP)
 Designed in the mid-1980's as an answer to the communication
problems between different types of networks.
 Consists of a simply composed set of network communication
specifications that cover all the basics of network management
in a method that poses little stress on an existing network.
 Each SNMP device (router, gateway, server) has an agent that
collects information about itself and the message it processes,
and stores that information in a database called the
management information base (MIB) .
Business Data Communications,
4e
12
Role of SNMP
 Transmission of a
message
 Receipt of a
message
 Variable bindings
Business Data Communications,
4e
13
SNMP
 The network management software has access to these
MIBs. A network manager can use this software to send
control messages to individual devices or groups of
devices asking them to report the information stored in
their MIB.
 Network information is exchanged through the
messages called protocol data units (PDU's). The PDU
can be looked at as an object that contains variables
that have both titles and values.
Business Data Communications,
4e
14
SNMP
 Five types of PDU's employed to monitor a network:
two deal with reading terminal data,
 two deal with setting terminal data,
 and one, the trap, is used for monitoring network events
such as terminal start-ups or shut-downs.
 To see if a terminal is attached to the network, a user uses
SNMP to send out a read PDU to that terminal.



If the terminal was attached to the network, the user would receive
back the PDU, it's value being "yes, the terminal is attached".
If the terminal was shut off, the user would receive a packet
informing them of the shutdown.
Business Data Communications,
4e
15
SNMPv2
 Released in 1992, revised in 1996
 Addressed functional deficiencies in
SNMP
 Accommodates decentralized network
management
 Improves efficiency of data transfer
Business Data Communications,
4e
16
SNMPv3
 Released in 1998, addressed security
deficiencies in SNMP and SNMPv2
 Does not provide a complete SNMP capability;
defines an overall SNMP architecture and a
set of security capabilities for use with
SNMPv2
 Provides three important services:
authentication, privacy, and access control
Business Data Communications,
4e
17
Common Management
Interface Protocol (CMIP)
 CMIP was designed to build on SNMP by making up
for SNMP's shortcomings and becoming a bigger,
more detailed network manager. Its basic design is
similar to SNMP, whereby PDU's are employed as
variables to monitor a network. CMIP however
contains 11 types of PDU's.
 The biggest feature of the CMIP protocol is that its
variables not only relay information to and from the
terminal (as in SNMP), but they can also be used to
perform tasks that would be impossible under SNMP.
 Problem: Too wonderful to be implemented.
Business Data Communications,
4e
18
Remote Monitoring (RMON)
 A standard that provides managers with real-time
network and application data for LANs.
 The major benefits of RMON:






Powerful Monitoring and Analysis
Historical Trending of the Local Segment
Traditional Protocol Decode Functions
Centralized Monitoring of Remote Sites
Multi-vendor Interoperability
Event Creation on Reaching Predefined Thresholds
 RMON is supported by SNMP
 Newer version is RMON2
Business Data Communications,
4e
19
How RMON Works
 Enables MIB information to be stored
on the device itself or on distributed
RMON probes that store MIB
information closer to the devices that
generate it.
 No transmission from MIB to the central
server until requesting the data.
 RMON reduces network traffic.
Business Data Communications,
4e
20
*RMON and RMON2
Business Data Communications,
4e
21
*Multi-Router Traffic Grapher
(MRTG)
 MRTG is a tool to monitor the traffic load on
network-links.
 MRTG generates HTML pages containing GIF
images which provide a LIVE visual
representation of this traffic.
 MRTG is based on Perl and C and works
under UNIX and Windows NT.
 MRTG is being successfully used on many
sites around the net. (MRTG-Site-Map).
Business Data Communications,
4e
22
*LANWatch32
 Precision Guesswork's LANWatch32 Network Analyzer
for Windows 95/NT is a software solution targeting
the complex task of network analysis.
 Decodes over 60 network protocols, including: TCP,
UDP, IP, IPv6, NFS, NFS (version 3), NetWare, SNA,
AppleTalk, VINES, ARP, and NetBIOS.
 Media Supported



Ethernet (802.3) 10 Mb/100 Mb
Token Ring (802.5)
Serial Line
Business Data Communications,
4e
23
*Demonstration
 http://www.rad.com/networks/1998/sn
mp/snmp.html
Business Data Communications,
4e
24