The user enters the following information to describe the SNMP manager IP, SNMP write-access, and the SNMP MIB object. The SNMP write-access and SNMP MIB object fields allow the service provider to set arbitrary SNMP attributes on the modem. For the Cisco uBR924 cable modem, these two fields are typically used to enable SNMP management of the Cisco uBR924 cable modem because SNMP management is disabled by default. The user can enable SNMP management by filling in the IP address for the SNMP manager. The Cisco DOCSIS CPE Configurator then prepares the proper MIB objects to enable SNMP access.
This is the IP address of the SNMP manager. The modem uses this address to report a problem with the cable network. (For information on IP addressing, see the RFC 1918 specification.)
Example:
192.65.178.5
This field makes it possible to disable SNMP write-access to individual MIB objects. Each instance of this object controls access to all of the writable MIB objects whose object ID (OID) prefixes match. This object can be repeated to disable access to any number of MIB objects. Each instance should contain the appropriate OID prefix plus one byte for the control flag. The control flag can take values:
To enable write-access (1)
To disable write-access (0)
Any OID prefix can be used. The Null OID 0.0 can be used to control access to all MIB objects. (The OID 1.3.6.1 has the same effect.) When multiple instances of this object are present and overlap, the longest (most specific) prefix has precedence.
Example:
1.3.6.1.2.1.69.1.6.4.1 (enables write-access to docsDevFilterIP) <Return>
1.3.6.1.2.1.69.1.6.4.1.17 (disables write-access to docsDevFilterIpTos)
In this example, everything in the docsDevFilterIP group is enabled up to (and excluding) the docsDevFilterIpTos group.
This allows arbitrary SNMP MIB objects to be set using the TFTP registration process. The VarBinds are entered as basic OID strings or ASCII values. These OID strings or ASCII values are converted to ASN.1 basic encoding rules by the Cisco DOCSIS CPE Configurator, just as it would be if part of an SNMP set request. The modem treats this object as if it were part of an SNMP set request with the following caveats:
The SNMP set request MUST treat the request as fully authorized (it cannot refuse the request for lack of privilege).
SNMP write-access control provisions do not apply.
No SNMP response is generated by the modem. This object can be repeated with different VarBinds to set a number of MIB objects. All such sets must be treated as if simultaneous.
Each VarBind MUST be limited to 255 bytes in length and each entry MUST be separated by <Return>.
Example:
Object ID: 1.3.6.1.2.1.10.127.1.1.3.1.2
Type: Integer
Value: 4
The user can specify the OID for the SNMP variable that is being set. Each OID has its "type" defined. The "type" will include one of these variables: Integer, Counter, Gauge, IP address, or Octet string. This "type" is defined in the MIBs files provided by the modem manufacturer. These DOCSIS-standard MIBs define what SNMP variables (OIDs) can be set.
For OID mapping of SNMP MIBs, see DOCSIS MIBs Table (Cisco IOS 12.0 T) for Cisco IOS Release 12.0 T or DOCSIS MIBs Table (Cisco IOS 12.1 T) for Cisco IOS Release 12.1 T.
To set up SNMP community strings, see SNMP Community String FAQs or to set up SNMP LLC and IP filters, see SNMP Filter FAQs.
DOCSIS MIBs Table (Cisco IOS 12.0 T)