Configuring Network Management-Specific Interface Index; About The Network Management-Specific Interface Index; Switching The Format Of An Nm-Specific Ifindex - HP A3100-8 v2 EI Configuration Manual

Configuring network management-specific
interface index

About the network management-specific interface index

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 formats:
16-bit NM-specific ifindex—A 16-bit NM-specific ifindex value contains 16 bits and ranges from 1
•
to 65534. The NM-specific ifindex value of each interface is allocated dynamically and increased
sequentially. The 16-bit NM-specific ifindex is an index value without any syntax explanation, and
only uniquely identifies an interface.
32-bit NM-specific ifindex—A 32-bit NM-specific ifindex value contains 32 bits, as shown in
•
33. The value is composed of the following parts: Chassis ID, Slot ID, interface type, and interface
offset.
Figure 33 32-bit NM-specific ifindex
• Offset—This field is 16 bits in length and distinguishes different interfaces of the same type on the
same interface board.
• Interface type—This field is 7 bits in length and is the enumerated value corresponding to the
interface type. It supports up to 128 different interface types and supports more than 80 interface
types.
• Slot ID—Number of the physical slot in which the interface resides, with the length of 5 bits.
Chassis ID—This field is 4 bits in length. For a distributed IRF fabric, this field indicates the member
•
ID of the device to which the interface belongs. For other devices, this field has no meanings and
the value is 0.

Switching the format of an NM-specific ifindex

An NM-specific ifindex adopts the default format (16-bit format). When either of the following scenarios
appears, you need to switch the format of the NM-specific ifindex using the following guidelines:
• If the NMS requires a 32-bit NM-specific ifindex, switch the format of the NM-specific ifindex to
32-bit format, which carries interface information, such as the number of the slot in which the
interface resides. If the NMS only supports 16-bit NM-specific ifindex values, the NMS cannot
recognize 32-bit NM-specific ifindex values. Make sure that the NM-specific ifindex values on the
device are 16-bit.
If the network protocol operating on the device does not support 32-bit NM-specific ifindex values,
•
make sure that NM-specific ifindex values on the device are 16-bit. For example, each packet of
NetStream version 5 or version 8 only reserves 16 bits for the ifindex, and the NM-specific ifindexes
must be in the 16-bit format. Each packet of NetStream version 9 reserves 32 bits for the ifindex, and
the NM-specific ifindexes can be in either 16-bit format or 32-bit format.
Follow these steps to switch the format of an NM-specific ifindex:
86
Figure