Network Management Concept

By Raul Bernardino
Introduction:
Nowadays, the network management has become very complex issues; this is starting from a single host to a millions hosts round the globe. We simple just don’t know who they are in the globe networks. Therefore, it is important to treat network management as an integral part of the network infrastructure management. Moreover, it is to enable us in monitoring and controlling the traffics. It is also enable us in maintaining all resources such as hardware, software, system configuration, and etc.

The Management Information Base (MIB) is virtual storage information of the objects that transmits through the networks. As per 2006, there were more than 200 standards of the MIB modules. The Internet Engineering Task Force (IETF) is a group of individuals that care about internet quality, influence designers, and manage the internet. They (IETF) adopted these standards and standardized this object identification with framework of the Open System Interconnection (OSI). The OSI object identifier tree can be sees in the diagram below:

Q1a:  The ‘1.2.840.113549’ standards object identifier (OIDs) is for the RSADSI.  Where the ‘1’ is for ISO assigned OIDs, ‘1.2’ is for ISO member body, ‘1.2.840’ is for USA, and ‘1.2.840.113549 is for RSADSI.

Q1b: The new Microsoft file format product in the OIDs tree is ‘1.2.840.113556.4.x’. Where ‘1’ is for ISO assigned OIDs, ‘1.2’ is for ISO member body, ‘1.2.840’ is for USA, and ‘1.2.840.113556 is for Microsoft, ‘1.2.840.113556.4’ is for Microsoft file format, and ‘1.2.840.113556.4.x’ is for new product of Microsoft file format.

Q2: The SNMP stands for Simple Network Management Protocol. The message types and functions over the SNMP protocol as it shows in the table below:

The big differences of the trap and request respond messages in SNMP as follows:

-         The trap message: the SNMP agent sent message to the SNMP manager and it is not requiring any responds from the SNMP manager, and it is including sent inform request and respond; as it shows in figure 1, 2 and diagram below:

 Figure 1 Trap Sent to SNMP Manager Successfully

 Figure 2 Inform Request Sent to SNMP Manager Successfully

However, if it is unsuccessful during trap message sent, the SNMP agent does not know the trap has reached the destination and the SNMP manager also does not receive any inform request as it shows in figure 3 below:

The agent sent several inform request from SNMP agent to the SNMP manger on the trap model until it reaches the SNMP manger; as it shows in figure 4 below:

-         While the request and the response messages are sent by the agent to manager entity, with the response coming back from the manager entity; as it shows in diagram below:

Q3: The Internet has no presentation layer. Additionally, in the table of the TCP/IP layer in which has four layers according to the IETF were defined in RFC 1122:

We can compare the TCP/IP layer with 7 OSI layers as in diagram below:

The application layer in the TCP/IP is representing application, presentation, and session layers in the OSI layer. While internet layer in the TCP/IP represents network and data-link layer in the 7 OSI layers. Other literatures especially bottom up approach split link layer in to two layers such physical and data-link layer then TCP/IP layer become five layers.  

Moreover, network topology diagram below is illustrated two Internet host computers are communicating through the local network boundaries comprised with the routers.

 The SNMP engine and application will be taking care of the differences of the machine architecture, data format, message processing, and it is including the security of data communication over the network. As it shows in diagram below:

Furthermore, the message format over Protocol data Unit (PDU) as it shows in diagram below:

Q4: Before I am going to answer the question, I have to elaborate the ASN.1. The ASN.1 stands for Abstract Syntax Notation 1 which is the ISO’s that used numbers in the internet protocol, especially in the network management. The question was how each of computers can read those transmitted data from different architecture and program as it shows in diagram below:

The issue is on data formats and storage conventions. Potential solutions as follows:

a)     The senders are learning format from the receivers.  In the real world analogy may not apply. There is still pro and cons.

b)    The receivers are learning the sender’s format. In the reality this can be a real world analogy however there is still pro and cons.

c)     Senders and receivers are translate independently each own format. It is not fitted with real world analogy.

The scenario above can be illustrated  in a diagram below:

In order to solve situation above:

1.     Translate local host format in to independent host format

2.     Translate data in to independent host format

3.     Translate independent host format to the remote host format

 As it shows in diagram below:

The ASN.1 provides several things such as:

1.     In the ISO standard X.680 is used extensively in the internet

2.     To define data type and object constructor like SMI (Structure of Management Information)

3.     BER stands for Basic Encoding Rule in which the ASN.1 will define data object to transmit. Where each transmission of the object has a type, length, and value (TLV) encoding.

The TLV has tag value and type as follows:

Tag Value   Type                              Description

1                 BOOLEAN                    Value is true or false

2                 INTEGER                      Can be arbitrary large

3                 BITSTRING                  List of one or more bits

4                 OCTET STRING                    List of one or more bytes

5                 NULL                            No value

6                 OBJECT IDENTFIER   Name, in ASN.1 standard naming tree

9                 REAL                            Floating point

Example of the BER in the TLV encoding for character string “Smith” with value 259 as it can be illustrated in a diagram below:

The answer for strings “greg” and value 277. The binary for the decimal of 277 is 00000001 00010101. The first binary value is 1 and followed by value of the byte is 21. The first byte of the stream value is 4 in which indicating type of data is OCTET STRING and the length of OCTET STRING is 4 (“greg”); followed by 2 integers (type of data and length of integer).  The result is ” 4 4 ‘g’ ‘r’ ‘e’ ‘g’ 2 2 1 21”, as it can be illustrated in a diagram below:

Reference List:

1.     Kurose, J.F. & Ross, K.W. (2010) Computer Networking: A Top-Down Approach. 5^th ed. Boston: Addison Wesley

2.     University of Liverpool/Laureate Online Education (2011) Lecture notes from Computer Networking Module Seminar8 [Online]. Available from: University of Liverpool/Laureate Online Education VLE (Accessed: 21 September 2011).

3.     Cisco IOS Software Releases 11.3: SNMP Inform Requests, [Online]. Available from: http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/snmpinfm.html (Accessed: 27 September 2011)

4.     The deference between TCP/IP and OSI layer, [Online]. Available from:  http://forums.techarena.in/technology-internet/1113879.htm (Accessed: 27 September 2011)

5.     Network Management Review question, [Online]. Available from:  http://subjects.ee.unsw.edu.au/tele4354/downloads/revCh9.pdf (Accessed: 27 September 2011)

6.     RSA data security Inc, [Online]. Available from:  http://www.alvestrand.no/objectid/1.2.840.113549.html  (Accessed: 27 September 2011)

7.     Wikipedia (N), OSI model, [Online]. Available from:  http://en.wikipedia.org/wiki/OSI_model (Accessed:  30 September 2013)

8.     Website (N), The internet engineering Task Force, [Online]. Available from: http://www.ietf.org/(Accessed:  30 September 2013)

9.     Wikipedia (N), Protocol Data Unit, [Online]. Available from: http://en.wikipedia.org/wiki/Protocol_data_unit (Accessed:  30 September 2013)