Transcript Basic Ingredients of Network Management

Basic component of Network
Management
Woraphon Lilakiatsakun
Basic components
• Fig 3-1
The Network devices
• It is also called “Network Element”
• NE must offer a management interface to allow
•
•
managing system to communicate with
So, NEs. have to run a process as “Management
Agent”
Management communication
– Manager - a managing application who in charge of
the management
– (Management) Agent – support the manager by
responding to its requests and notifying unexpected
events
Manager-agent communication
• Fig 3-2
Management Agent
• A management interface – handle
management communication
• A Management Information Base (MIB)conceptual data store (management
information) that contain management
view of the device being managed
• The core agent logic – translates between
the operation of the management
interface, the MIB and the actual device
Management Interface (Logical)
• Process to interact with the agent
– Support a management protocol that defines the
rules of conversation for communication between
the managed network element
• For example
– Allow an application to open (and tear down)
management session with the agent
– Allow an application to make management requests
to the NE (requests to retrieve statistical data)
– Allow NE to send unsolicited event messages to an
application
Management Information Base
(MIB) (1)
• Management operations are directed against
•
the conceptual view
– The network ports of a NE could be
represented as a table in an imaginary
database with each port having a
corresponding entry in the table
MIB is not a real database ,it works as a proxy
of the NE that affects to the actual device
– When MA modifies entry in the conceptual
table , the actual configuration of device is
also changed
Management Information Base
(MIB) (2)
Management Information Base
(MIB) (3)
• MIB related standard
• RFC 1155
– Structure and Identification of Management
Information for TCP/IP based internets
• RFC 1157
– Simple Network Management Protocol
• RFC 1213
– Management Information Base for Network
Management of TCP/IP-based internets
Management Information Base
(MIB) (4)
OID = 1.3.6.1
(internet)
OID = 1.3.6.1.4.1.2682.1
(dpsAlarmControl)
MIB – OID Tree
Core agent logic
• Translates between the operation of the
management interface, MIB, and actual device
– Translate the request to “retrieve a counter” into an
internal operation that reads out a device hardware
register.
• Additionally, it can include more management
functions (embedded management intelligence)
that offload the processing required by
management app.
– Pre-correlated raw events before sent out
– Schedule a periodic test function instead of sending
new test request each time.
An anatomy of management
agent
• Fig 3-4
Management Information
• Management information provides an
abstraction of the real-world aspects for
management purposes
– The version of installed software - to decide
which devices need to have new software
– Utilization of port - whether capacity upgrades
are necessary
– Packet counter for different interfaces –
indicate that a network is under attack (DoS)
Managed Object (1)
• We refer a chunk of management
information that expose of these realworld aspects as a managed object (MO)
– A device fan along with its operational state
– A port on a line card along with a set of
statistical data
Managed Object (2)
Managed Object (3)
• Not all aspects in the real world are modeled
– Color of devices
• Real world object that MO represents is referred
•
to as the “real resource”
Since management information in MIB represents
real resource
– When querying the MIB for MO representing a packet
counter 3 times, the value returned will be different
– When modifying information in the MIB to perform
certain updates , it will affect the real world.
Basic parts of network
management - refined
• Fig 3-6
The Management System (1)
• Tools to manage the network
– Monitor the network
– Service provisioning system
– Craft terminal
• A management system can run one or more
hosts
– Distributed across several hosts
– Scalability
– More robust
The Management System (2)
• Roles in Network
Management System
– Manager / Agent
• Sometimes, one network
element can play two
roles as figure
The Management System (3)
• Fig 3-8
Manager/agent reference diagram
The Management System (4)
• Fig 3-9
Caching MIB
The Management System (5)
• Pros for caching MIB
– avoid having to go back to the NE repeatedly
for the same information
• Cons for caching MIB
– The cache is stale
The Management Network (1)
• Networks for carrying traffic of
subscriber or end user are referred as
“production network”
• Networks for carrying management
traffic are referred as “management
network”
• Both can be physically separate
networks or they can share the same
physical network
The Management Network (2)
Connecting a craft terminal to a managed device
and use CLI to configure and troubleshoot
the network device
The Management Network (3)
• Fig 3-11
Connecting to multiple devices through a terminal server
The Management Network (4)
• Fig 3-12
Dedicated Vs Shared Management and Production networks
The Management network (5)
• Pros of a dedicated management network
• Reliability
– Congestion or network failure occurs
somewhere in the network, it makes the
devices hard to reach
• Management traffic will be impacted
• Hard to find out what it is happening
The Management network (6)
• Pros of a dedicated management network
•
(Con’t)
Interference avoidance
– Compete with production traffic –data or voice traffic
– Not high volume but bursty characteristics may
interfere high QoS services (voice ,video streaming)
• Ease of network planning
– No need to consider on management traffic
• Security
– Hard to attack and more secure
The Management network (7)
• Cons of a dedicated management network
• Cost and overhead
– Addition cost for a management network
• No reasonable alternative
– Some devices do not provide a physical connection
for another usage
– DSL router cannot be connected with two physical
links
The Management network (7)
• Cost is the huge disadvantage
• So, the management network is needed
only critical area
– Backbone of service providers or big
enterprises
• Hybrid solution
– Generally, it shares over production
networks
– Only critical segments are used as
dedicated networks
The Management Support
Organization: (1)
• In term of Network – Network Operation
•
•
Center (NOC)
Telecommunication service provide refer to
management system as Operation Support
System
The management support Org. is responsible
for making sure that the network is being run
efficiently and effectively
The Management Support
Organization (2)
• Management tasks (not limited to these)
(1)
– Monitoring the network for failures
– Diagnosing failures and communication
outages
– Planning and carrying out repairs
– Provisioning new services and
adding/removing users
The Management Support
Organization: (3)
• Management tasks (2)
– Keeping an eye on performance of the
network and taking preventive measures
– Planning network upgrade
• To increase capacity and distribution of software
patches
– Planning network topology and network
buildout
• Ensure that the network will meet future
demands
The Management Support
Organization: (4)
• Organization structure
– Network planning - analyzing network usage and
traffic patterns and planning network buildout and
service rollout
– Network operation - keeping the network running and
monitoring the network failures
– Network administration – Deploying the network and
services on it
– Customer (user) management -Interacting with the
customers
The Management Support
Organization: (5)
Needed Activities (1)
– Establishment of process and operational
policies, documentation of operational
procedures
• Help management of the network consistent
and efficient and facilitates meeting a
consistently high standard of operations
• Well-defined workflow to ensure that things
that are supposed to happen do not fall
through cracks
• Well-defined escalation procedures to ensure
responsiveness
The Management Support
Organization: (6)
Needed Activities (2)
– Collection of audit trails
• Automatically logging the activities of
operations
• make it easier to reproduce what happened
and recover from situation in which human
error
– Network documentation
• Must be accurate and up-to-date
• Important for network planning and software
upgrades
The Management Support
Organization: (7)
Needed Activities (3)
– Reliable backup and restore procedures
• Bring network back to live again in case of disaster
and emergencies
– Security emphasis
• Networks potentially most vulnerable from the
inside
• Limit the damage that can cause by one person