Management Information Bases (MIBs)
The inventory in the switch system can be accessed through a MIB browser. These devices are indexed (entPhysicalIndex) using three layers:
- Module layer—includes modules located on system (e.g., cables, fan, power supply, and so forth). See the module type breakdown table for more details. 
- Device layer—a number identifying the specific device that is associated with the module (e.g., ASIC on a leaf, fan on the management board, and so forth). 
- Sensor layer—a number identifying the specific sensor that is associated with the device (e.g., fan sensors, temperature sensors, power sensors, and so forth). 
Each layer is assigned a fixed position in the SNMP index number that represent it.
The physical entities in the system (other than port modules) use the following index schema:
| Mod. Type ID | Module Index | Device Identifier | Sensor Type and Index | |||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 
| Layer 1 | Layer 2 | Layer 3 | ||||||
Spectrum-2 systems and above use the following index schema for port modules and port module sensors:
| Mod. Type ID | Port Module Identifier | Port module Sensor index TX sensors in range 1..39 RX sensors in range 41..79 | |||||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 
| Layer 1 | Layer 2 | Layer 3 | |||||||
Spectrum systems use the following index schema for port modules and port module sensors:
| Mod. Type ID | Port Module Identifier | Port Module Sensor Type 0 for TX 1 for RX | Sensor index | |||||
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 
| Layer 1 | Layer 2 | Layer 3 | ||||||
Module type breakdown:
| Number | Description | 
| 1 | Chassis | 
| 2 | Management | 
| 3 | Spine | 
| 4 | Leaf | 
| 5 | Fan | 
| 6 | Power supply | 
| 7 | BBU | 
| 8 | x86 CPU | 
| 9 | Port module | 
| Physical entities—10 digits representation | |
| 1 | Port module | 
Port module 9 digits representation is kept for backwards compatibility.
- entPhysicalIndex with value 401191311 - 9 digits representation. 
- Layer 1 is “401”—“4” indicates a leaf (see module type breakdown table) and “01” indicates leaf at index #1 (i.e., leaf 01) 
- Layer 2 is “1913”—this is the identifier for one of the QSFP-ASIC in the system 
- Layer 3 is “11”—this is the identifier for temperature sensor #1 
- The description for this physical entity (appears in entPhysicalDescr column of the MIB) would be: L01/QSFP-ASIC-1/T1 
 
- entPhysicalIndex with value 501020021 - 9 digits representation. 
- Layer 1 is “501”—“5” indicates a fan (see module type breakdown table) and “01” indicates fan at index #1 (i.e., fan 01) 
- Layer 2 is “0200”—this is the identifier for general fan in the system 
- Layer 3 is “21”—this is the identifier for fan sensor #1 
- The description for this physical entity (appears in entPhysicalDescr column of the MIB) would be: FAN1/FAN/F1 
 
- For entPhysicalIndex with value 1000012700 - 10 digits representation. 
- Layer 1 is “1”—port module (see module type breakdown table). 
- Layer 2 is “127”—port identifier 
- Layer 3 is “00”—no sensors for this port module 
 
- For entPhysicalIndex with value 1000012742 - 10 digits representation. 
- Layer 1 is “1”—port module (see module type breakdown table). 
- Layer 2 is “127”—port identifier 
- Layer 3 is “42”—sensor in the range 41..79 indicts an RX sensor