Switching the nm-specific interface index format, Configuration guidelines – H3C Technologies H3C WX5500E Series Access Controllers User Manual
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Step
Command
Remarks
8.
Set the DSCP value
for SNMP responses.
snmp-agent packet response dscp
dscp-value
Optional.
By default, the DSCP value for SNMP
responses is 0.
Switching the NM-specific interface index format
A network management (NM)-specific ifindex identifies an interface and is provided by the SNMP
managed device to the NMS. A network management-specific ifindex takes one of the following two
formats:
•
16-bit NM-specific ifindex—The system dynamically assigns 16-bit NM-specific ifindex values to
uniquely identify its interfaces. The 16-bit NM-specific ifindex value starts from 1 and increments by
1.
•
32-bit NM-specific ifindex—A 32-bit NM-specific ifindex value comprises an Offset, Interface Type,
Slot ID, and Chassis ID, as shown in
.
Figure 23 32-bit NM-specific ifindex
{
Offset—This field is 16 bits long and distinguishes different interfaces of the same type on the
same interface card.
{
Interface type—This field is 7 bits long and contains the enumerated value specific to the
interface type. It supports up to 128 different interface types and supports more than 80
interface types at present.
{
Slot ID—This field is 5 bits long and contains the number of the physical slot that holds the
interface.
Configuration guidelines
•
Use the 32-bit NM-specific ifindex format if the NMS requires the format to get information such as
the slot that contains a specific interface. If the network protocol operating on the NMS does not
support 32-bit NM-specific ifindex values, make sure NM-specific ifindex values on the device are
16-bit. By default, the device adopts the 16-bit NM-specific ifindex format.
•
If the device runs the version 5 or version 8 of NetStream, you must use the 16-bit format, because
the two NetStream versions reserve only 16 bits for the ifindex. NetStream version 9 reserves 32 bits
for the ifindex, so you can use either 16-bit or 32-bit NM-specific ifindex format.
•
An NM-specific ifindex format change invalidates the NM-specific ifindex dependent settings, and
these settings cannot become valid until you switch the format back. To use these settings in the new
format, you must re-configure them. For example, if an RMON alarm group or private alarm group
has alarm variables in the format OID/variable-name.NM-specific-ifindex, you must reconfigure
these variables after an NM-specific ifindex format change.
Slot ID
Interface Type
0
22
15
Offset
Chassis ID
27
31