Deployment Guide

Starting from the least significant bit (LSB) in the preceding figure:
● The first 14 bits represent the card type of a physical interface or the interface number of a logical interface.
● The next 4 bits represent the interface type.
● The next 12 bits represent the slot and port numbers.
● The next bit is 0 for a physical interface and 1 for a logical interface.
● The last next is unused.
The Slot-Port Number value is derived from the slotId and portId parameters as follows: slotPortNum = ((slotId +1) *
IFM_IFINDEX_MAX_PORTS_PER_SLOT + portId).
The IFM_IFINDEX_MAX_PORTS_PER_SLOT value is 192 (10G). For backward compatibility, the
IFM_IFINDEX_MAX_PORTS_PER_SLOT value is 128 on other Dell Networking switches.
The slotId value is derived as follows: slotId = (slotPortNum / IFM_IFINDEX_MAX_PORTS_PER_SLOT) -1.
The portId value is derived as follows: portId = slotPortNum % IFM_IFINDEX_MAX_PORTS_PER_SLOT.
For example, the interface index 51528196 for the FortyGigE 0/4 port is 0000 0011 0001 0010 0100 0010 0000 0100 in binary
format as shown in the following figure.
Figure 136. Interface Index Number Assigned to FortyGigE 0/4 Port
In this example, if you start from the least significant bit on the right:
● The first 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) identifies 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.
If you know the interface index, use the following commands to find 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]
Simple Network Management Protocol (SNMP)
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