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Network Management,

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Generic software hides complex network data as much as possible and presents ... access to sensitive NE data ... Restart the NE's or reloading the data files ... – PowerPoint PPT presentation

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Title: Network Management,


1
  • Network Management,
  • Management Information Base (MIB)s
  • and
  • Multiprotocol Label Switching (MPLS)
  • Principles, Design and Implementation
  • Stephen B. Morris
  • Chapter 6
  • Network Management
  • Software Components
  • By
  • Stanley Zurita Mohamed Abdallatif

2
NETWORK MANAGEMENTSOFTWARE COMPONENTS
  • There are many possible solutions to NMS
    development - this chapter describes one possible
    structure
  • Server-side components
  • Network-receiving asynchronous
  • Network-receiving synchronous
  • Network-sending
  • Database access
  • Client-side components
  • Middleware components
  • Data presentation, such as XML
  • Northbound interface

3
Figure 1
4
Typical servers provide the following functions.
  • Servicing client user requests
  • Issuing provisioning operations, such as writing
    to agent MIBS(inserting table entries,
    updating/deleting existing objects)
  • Special-purpose listening operations, such as
    monitoring LSP operational state
  • Providing generic service, such as scheduling
  • Providing specific service, such as NE, firmware
    and configuration data-base back-up, restore, and
    distribution
  • Handling incoming notifications from network

5
  • Database forms the glue that ties together the
    major component
  • Clients
  • Middleware
  • Server
  • NEs

6
Thin client tend not to use database directly and
instead rely on the server to manage the database
  • Recording client-initiated operations, such as
    creating FR or ATM virtual circuits
  • Storing the detail of scheduled operations and
    associated result

7
  • Thin client can be based on standard Web browser,
    there can be many such clients, and where to
    carry out bulk of the processing is an important
    design decision. If the principal requirement for
    client software is fast execution, then as much
    as possible of the MIB and database access should
    be carried out by the client rather than the MIB.
    If the client software is required to be simple
    and intuitive to use, then it should be designed
    to be as generic as possible. Generic software
    hides complex network data as much as possible
    and presents simple visual object proving default
    values where appropriate.

8
This involves setting the MIB object values for
  • Bit rate
  • Parity
  • Number of data bits
  • Number of start bits
  • Number of stop bits, and so on

9
Fault Server
  • The purpose of the Fault Server is to process NE
    notification. It faces into the network and seeks
    to maintain parity between the NMS picture of
    network faults and the real situation in the
    network. A Fault Server will generally provide
    the following features
  • Listening for notifications
  • Determining the underlying problem (root-cause
    analysis)
  • Updating persistent repositories and any GUI
    visual indicators

10
Fault Server Database Tables
  • Node ID(the Key)
  • Description A text string embedded in the
    notification explaining the fault
  • Origin The originating NE(processor, card,
    fabric,etc..) for the fault
  • Status active, cleared, acknowledged( the user
    knows about the fault but has not cleared it)
  • Color Red for active, blue for acknowledged,
    green for clear

11
Topology Update
  • CORBA
  • J2EE
  • JAVA RMI
  • RPC
  • Database update

12
Configuration Server
  • The purpose of the configuration server is to
    execute client-initiated directives made against
    NEs. Like the Fault Server, it also faces into
    the network but operates in less open-ended way
    because it is not required to process
    asynchronous NE-originated notifications.

13
Lets assume that a client user creates an LSP
(label Switched Path) there are three types
  • Signaled
  • Best-effort
  • Unidirectional

Origin Destination Signaling Protocol Required QoS Explict Route Object
LER1 LER2 LDP BEST EFFORT NONE
14
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15
Secure User
  • Security Setting
  • No authentication and no encryption
  • Authentication and no encryption
  • Authentication and encryption

16
Trace Files
  • Software bugs
  • SNMP timeouts, such as a third-party NE that has
    a slightly slow (or heavily loaded) agent
  • Bad values in MIB operations, such as trying to
    write an illegal value to a MIB object

17
Generic Connection Table Update
  • ATM virtual connection (PVX and SPVX0
  • MPLS LSP( signaled and unsignaled)
  • FR cross connections into an MPLS core
  • SONET path

18
Topology Update
  • Change the administrative status of a connection
    from up to down
  • Creating a new LSP
  • Deleting an existing LSP

19
Configuration Server Database Tables
  • Generic connection table these contain data
    relevant to all connection types Keyes by index
    value or origination/ destination node IDs
  • Technology-specific connection tables These
    contain data relevant to specific connection
    types, such as ATM PVX and LSPs
  • Operations log tables These are for recording
    configuration change
  • Operations result log tables These are recording
    all configuration change results

20
ACCOUNTING SERVER
  • Accounting and performance software share a
    number of similarities. The Accounting Server
    faces into the network and receives data record
    periodically generated by NEs. Often, the data
    records are emitted based on a preconfigured
    time. It is also possible for an accounting
    Server to poll MIBs for specific data ultimately,
    accounting data is concerned with billing users
    for network resources consumption.

21
Mediation
  • Mediation is the process of analyzing the raw
    data generated by NEs to produce standard format
    billing details for downstream use by third-party
    applications (from organizations such as
    ACECOMM). It is not necessary to use standard
    formats if the billing application is
    proprietary. However, standard format have the
    merit of allowing different third-party
    application to be swapped in as required.

22
Aggregation
  • This is the process by which separate CDRs are
    combined. An example is an ATM PVC that spans a
    number of NEs
  • Number of IP packets transported (if the circuit
    is an LSP)
  • Number of cells transported per second (if the
    circuit is an ATM connection)
  • Number of cells dropped due to excessive input
    traffic
  • Average bandwidth used by the cell traffic
  • Number of SLA contract violations

23
Correlation
  • Correlation is the process of combining multiple
    units of aggregated data with the details of the
    ultimate bill recipient, that is, one customer.
  • Number of cells sent to or received from the SP
    network
  • Bandwidth used in transporting the data across
    the ATM link

24
Reports
  • Utilization of objects, such as LSPs
  • The average and peak numbers of IP packets
    transported by the LEP
  • The bandwidth consumed

25
Performance Server
  • The purpose of the Performance Server is to
    analyze network data in order to
  • Determine if problems exist prior to their
    affecting services
  • Maximize network utilization
  • Pre-empt the occurrence of congestion
  • Demonstrate compliance with agreed SLAs
  • Indicate when extra network investment is
    needed(capacity planning)

26
SLA Alert
  • It is very important for enterprises to avoid
    violating SLA terms because there may be
    financial penalties.SLA alert can be issued based
    on ongoing analysis of trends in an effort to
    pre-empt violations before they actually occur.

27
Source IP address 10.81.1.45
Source Port 444
Destination IP address 10.81.2.89
Destination Port 445
Link Bandwidth 10Mbps
Interpacket Delay 1ms
Ordered Delivery Yes
Packet Loss 0.0001
Jitter No
Round Trip Delay 30ms
28
  • This SLA indicates that IP traffic from
    10.81.1.45 port 444 will land in the SP network
    on a 10Mbps link destined for 10.81.2.89 port
    445. The interpacket arrival time is specified to
    be no more than 1 millisecond with no packet
    arriving out of order. A tunneling technology
    such as MPLS or L2TP could be employed to achieve
    the latter.

29
Topology Update
  • When congestion is imminent on a given link
  • When a virtual circuit is being presented with
    excessive traffic-it may be necessary to add
    extra bandwidth to the circuit

30
Performance Server Database Tables
  • Nodes
  • Interface
  • Links
  • Virtual connections
  • Each table has separate columns for relevant
    performance
  • Number of incoming and outing packets, cells, and
    frames
  • Bandwidth in use
  • SLA status

31
Security Server
  • If there is one area of network management that
    has moved to the top of the operators, agenda,
    it is security,
  • Access application SNMP, telnet, secure shell,
    Web, console( serial port)
  • Authentication Password, community string,
    Kerberos, user-based security Remote Access
    Dial-In User Service (RADIUS)
  • Privilege level Super user, Read-only, and User
  • Permitted views Specific objects and sources

32
Access Applications
  • Limited or no logging apart from that provided by
    the NE or CLI
  • Fairly open access to sensitive NE data
  • It may be error-prone, and help facilities may be
    quite limited

33
Some popular access applications are
  • SNMP
  • Telnet
  • Secure Shell
  • Web

34
Authentication Privilege Level
  • Read-only
  • User-level
  • Superuser
  • Read-only access allow only MIB get user-level
    allows gets and some sets superusers can get and
    set all appropriate

35
Permitted Views
  • Access control list
  • Permitted object views
  • An access control list contain the source IP
    addresses allowed to connect to an NE. Permitted
    object views specify a subset of MIB object
    accessible to a given NMS user

36
Discovery Server exist to keep up with the detail
of the deployed NEs Discovery keep track of
  • Nodes
  • Interface and underlying stacks
  • Links
  • Virtual connection
  • Cross connections between different technologies
  • Routing protocols
  • Routing Tables
  • Signaling protocols
  • ICMP
  • SNMP
  • Standard and proprietary signaling protocols

37
NE Software Distribution
  • FTP/TFTP
  • Proprietary download mechanisms
  • Using an NMS

38
Distributing NE in step
  • Preparing the NE for a new firmware load
  • Rerouting traffic around any nodes to which
    downloads are pending
  • Initiating the transfer
  • Handling rollback if the transfer fails
  • Verifying the transfer succeeded
  • Starting up the new NE software

39
Preparing the NE may involve
  • Bring the NE into a quiescent state
  • Closing down existing connections
  • Ensuring that no resource are in use on the NE
  • Determining the available FLASH and RAM free
    space
  • Taking a copy of the existing firmware

40
NE Configuration Database Backup and Restore
  • Some reason for backing up
  • New firmware build may upgrade the configuration,
    making rollback difficult
  • Disaster recovery
  • Creating Mirror network
  • Using a given configuration as a template

41
NMS should handle the complexities of
  • Knowing where the appropriate configuration data
    flies are located
  • Handling the transfer via FTP, TFTP, and so on
  • Restart the NEs or reloading the data files
  • Informing the operator when the operation is
    complete
  • Rerouting traffic around the nodes being restored

42
Middleware
  • Middleware is the part of an NMs that allow
    communication between the clients and servers,
    There is a broad range of software technology
    choices for achieving this, including
    RPC,JAVA,COBRA, J2EE, and Microsoft.Net

43
SUMMARY
  • The implementation of NMS software can take the
    form of sever .These are high perform software
    objects that can support interaction with both
    external clients and NEs, It is essential that
    server are resilient and designed so that they
    are unlikely to fail except in exceptional
    circumstances. They form the intermediate layer
    through which end users can securely communicate
    with NEs.

44
  • The need for generic software components is
    growing with the increasing deployment of dense,
    multiservice NEs Generic software attempts to
    abstract complex NE data as much as possible and
    present simple GUIs applicable across a broad
    range of devices.
  • On the client side, GUI views are often depicted
    as network topologies accompanied by fault
    listings, It is a major challenge for the NMS
    software to keep these views synchronized with
    the network. It is always hard to escape form
    legacy NEs, and for this reason it is often
    necessary for server components to be SNMP
    multilingual, that is able to use any of
    SNMPv1/2c/3.
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