Electrical computers and digital processing systems: multicomput – Network computer configuring – Reconfiguring
Reexamination Certificate
2000-05-03
2001-09-04
Meky, Moustafa M. (Department: 2153)
Electrical computers and digital processing systems: multicomput
Network computer configuring
Reconfiguring
Reexamination Certificate
active
06286040
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of computer networking. More particularly, the present invention relates to a user-friendly tool or interface for setting expressions via SNMP (Simple Network Management Protocol) on an SNMP agent having an expression management information base (MIB).
2. The Background Art
SNMP (Simple Network Management Protocol) is a protocol used in managing computer networks. It provides a systematic way of monitoring and managing a computer network and has become the standard in network management. The SNMP model of a managed network consists of four types of components: (1) managed nodes, (2) management stations, (3) management information, and (4) a management protocol. The managed nodes can be hosts, routers, bridges, printers, or any other devices capable of communicating status information to the management stations. Management stations monitor and manage the devices on the network. The management information contains information on the components of the network and the management protocol is the format in which this information is communicated to the management system.
FIG. 1
is a block diagram which illustrates an example of a network utilizing the SNMP model. Management station
10
controls a plurality of nodes
12
a
,
12
b
,
12
c
which in the figure include two computers
18
a
,
18
b
at nodes
12
a
,
12
b
respectively, and a printer
20
at node
12
c
. In order for an SNMP management station
10
to manage a node directly, the node must be able to run an SNMP agent, which is an SNMP management process normally encoded in software (although a hardware implementation for use with certain nodes is also possible). Almost all computers meet this requirement, as well as some bridges, routers, printers, and similar peripheral devices which are specifically designed for use in a network. In
FIG. 1
, the agents
14
a
,
14
b
running on each of the computers
20
a
,
20
b
respectively, would most likely be encoded in software whereas the agent
14
c
for the printer
20
would most likely be a hardware implementation.
Many networks contain components manufactured by several different companies. In order for the management station to communicate effectively with these varied devices, the nature of the information maintained by the agents must be rigidly specified. SNMP therefore describes the exact information each agent must maintain and the format in which it must be maintained in data structures called management information bases (MIB).
Each SNMP agent maintains a local database of variables that may describe the current and past state of the node to which it is assigned as well as provides instructions to affect the operation of the node. The management of the network is then carried out by the management stations. The management stations have one or more processes that communicate with the SNMP agents through the network by issuing commands and getting responses. One of the advantages of this design is that much of the complexity of the system is located in the management stations, rather than in the SNMP agents, allowing the agents to be as simple as possible to minimize their effect on the nodes on which they are running.
In the SNMP protocol, each SNMP agent may maintain one or more variables that describe the node's state. These variables are also called objects. Related managed objects are grouped together in a data structure called a management information base (MIB).
FIG. 2
illustrates two different examples of SNMP agents. The first agent
30
contains a management information base
32
. It is also possible to have multiple management information bases within each agent, as seen in the second agent
40
, which contains management information bases
36
and
38
. In addition, each node on the network may have different types of management information bases. Referring to
FIG. 2
, the first agent
30
contains both a MIB
32
and an expression MIB
34
. An expression MIB is a special type of MIB which is discussed below. The second agent
34
also contains an expression MIB
42
as well as management information bases
36
,
38
.
The management station communicates with the agents over the network using the SNMP protocol, which allows the management station to query the state of the agent's local objects and modify them if necessary. Therefore, the management station communicates with the management information bases of each agent. There are four SNMP operations defined in version 1 of SNMP. These are “Get”, “Get-next”, “Set”, and “Trap”. “Get” retrieves an object instance from the agent. “Get-next” retrieves the next object instance from a table or list within an agent. “Set” sets object instances within an agent and “Trap” informs asynchronously the network management station of some event.
SNMP messages contain two parts: a message header and a protocol data unit. The message header comprises a version number and a community name. The community name serves to define an access environment for a set of network management stations using the community name. Additionally, since devices that do not know the proper community name are precluded from SNMP operations, network managers may also use the community name as a weak form of authentication.
The data portion of an SNMP message contains the specified SNMP operation (“Get”, “Get-next”, “Set”, or “Trap”) as well as associated data.
FIG. 3
depicts the format for the data, or protocol data unit, portion. The format for a “Get”, “Get-next”, or “Set” command
50
includes four fields. The first is a request-ID field
52
, which associates requests with responses. The next is an error status field
54
, which indicates an error and an error type. The next is an error index field
56
, which associates the error with a particular variable in the variable bindings. The last is a variable bindings field
58
, which comprises the data. Each variable binding associates a particular variable with its current value (except in “Get” and “get-next” requests, where the value is ignored).
The format for a “Trap” command
66
includes six fields. The first is an enterprise field
62
, which identifies the type of the object generating the trap. The next is an agent address field
64
, which provides the address of the object generating the trap. The next is a generic trap type field
66
, which provides the generic trap type. The next field is a specific trap type code
68
, which provides the specific trap type. The next field is a time stamp field
70
, which provides the amount of time that has elapsed between the last network reinitialization and generation of this trap. The last field is the variable bindings field
72
, which provides a list of variables containing interesting information about the trap.
Version 2 of SNMP introduced two new operations: “Inform” and “Get-bulk”. “Inform” allows one manager to send trap type information to another manager and request a response. “Get-bulk” allows a manager to retrieve efficiently large blocks of data, such as multiple rows in a table, which would otherwise require the transmission of many small blocks of data. The message format for the data portion of SNMP version 2 commands is depicted in FIG.
4
. For “Get”, “Get-next”, “Inform”, “Set”, and “Trap” functions, the format
80
comprises five fields. The first field is a PDU type field
82
, which identifies the PDU type (get, get-next, etc.). The second field is a request ID field
84
, which associates requests with responses. The third field is an error status field
86
, which indicates an error and an error type. The fourth field is an error index field
88
, which associates the error with a particular variable in the variable bindings. The fifth field is a variable bindings field
90
, which associates particular variables with their current values (except for the get and get-next requests, which ignore this value).
For the “Get-bulk” operation, the format
92
includes five fields. The first and second fields are
Durham Sandra
Kavasseri Ramanathan
Cisco Technology Inc.
Meky Moustafa M.
Ritchie David B.
Thelen Reid & Priest LLP
LandOfFree
User-friendly interface for setting expressions on an SNMP... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with User-friendly interface for setting expressions on an SNMP..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and User-friendly interface for setting expressions on an SNMP... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2542645