Concept Guide
Figure 136. Interface Index Number Assigned to FortyGigE 0/4 Port
In this example, if you start from the least signicant bit on the right:
• The rst 14 bits (00001000000010) identify a line card.
• The next 4 bits (1001) identify a 40-Gigabit Ethernet interface.
• The next 12 bits (000011000100) identify slot 0 and port 4.
• The next bit (0) identies a physical interface.
• The last bit is always 0, which means that it is unused.
NOTE: The interface index does not change if the interface reloads or fails over.
Example of Deriving the Interface Index Number
If you know the interface index, use the following commands to nd the interface number.
DellEMC ~ $ snmpwalk -v 2c -c public 10.16.206.127 .1.3.6.1.2.1.2.2.1.2 | grep 2097156
IF-MIB::ifDescr.2097156 = STRING: TenGigabitEthernet 1/1
DellEMC ~ $ snmpwalk -v 2c -c public 10.16.206.127 .1.3.6.1.2.1.31.1.1.1.1 | grep 2097156
IF-MIB::ifName.2097156 = STRING: TenGigabitEthernet 1/1
You can use the show interfaces command to view the interface index.
Dell#show interface fortyGigE 0/4
fortyGigE 0/4 is down, line protocol is down
Description: if_0/4 | if_forty
Hardware is DellForce10Eth, address is 74:86:7a:ff:6f:08
Current address is 74:86:7a:ff:6f:08
Pluggable media not present
Interface index is 2097156
[output omitted]
Monitoring BGP sessions via SNMP
This section covers the monitoring of BGP sessions using SNMP.
BGP SNMP support for non-default VRF uses a SNMP context to distinguish multiple BGP VRF instances within a single BGP process.
SNMP context is a repository of management information that can be accessed through the SNMP agent. SNMP supports multiple
contexts in a device. SNMPv3 has a context name eld in its PDU, which automatically allows the context name eld to be mapped to a
particular VRF instance without having to be mapped to a community map. SNMPv2c context has to be mapped to a community map. A
new CLI command,
snmp context, under BGP context, has been introduced to perform this function.
To map the context to a VRF instance for SNMPv2c, follow these steps:
1 Create a community and map a VRF to it. Create a context and map the context and community, to a community map.
• sho run snmp
• snmp-server community public ro
• snmp-server community public ro
Simple Network Management Protocol (SNMP)
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