Information Technology Reference
In-Depth Information
Memory
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Standard protocols
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From the Cisco private tree, you can obtain additional information such as the following:
Small, medium, large buffers
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Primary and secondary memory
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Proprietary protocols (Enhanced Interior Gateway Routing Protocol [EIGRP]), for
example)
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Yo u can find more specific information about Cisco MIBs at
www.cisco.com/public/
SNMP Message Versions
SNMPv1 was initially defined by RFC 1157. Since then, SNMP has evolved with a second
and third version, each adding new message types. The CCDA should understand each
message type and the version associated with each.
SNMPv1
SNMPv1 is defined by RFC 1157. It is a simple request-and-response protocol. The NMS
manager issues a request, and managed devices return responses. The date types are lim-
ited to 32-bit values. SNMPv1 uses four protocol operations, with five message types to
carry out the communication:
Get request:
Retrieves the value of a specific MIB variable.
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GetNext request:
Retrieves the next instance of the MIB variable.
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Get response:
Contains the values of the requested variable.
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Set request:
This is a request from the manager to the agent to set a MIB variable. It
can be used to modify the agent's configuration.
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Trap:
Tran s mits an un s olic ited alar m condit ion.
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Figure 15-3 shows the SNMPv1 message types.
NMS
Manager
Get Request
Get Response
GetNext
Set Request
Trap
Agent
Figure 15-3
SNMPv1 Message Types
