538 | Simple Network Management Protocol (SNMP)w w w . d e l l . c o m | s u p p o r t . d e l l . c o mDeriving Interface IndicesFTOS assigns an interface number to each (configured or unconfigured) physical and logical interface.Display the interface index number using the command show interface from EXEC Privilege mode, asshown in Figure 30-26.Figure 30-26. Display the Interface Index NumberThe interface index is a binary number with bits that indicate the slot number, port number, interface type,and card type of the interface. FTOS converts this binary index number to decimal, and displays it in theoutput of the show interface command.Figure 30-27. Interface Index Binary CalculationsStarting from the least significant bit (LSB):• the first 14 bits represent the card type• the next 4 bits represent the interface type• the next 7 bits represent the port number• the next 5 bits represent the slot number• the next 1 bit is 0 for a physical interface and 1 for a logical interface• the next 1 bit is unusedFor example, the index 44634369 is 10101010010001000100000001 in binary. The binary interface indexfor TenGigabitEthernet 0/41 of an MXL Switch is shown in Figure 30-28. Notice that the physical/logicalbit and the final, unused bit are not given. The interface is physical, so this must be represented by a 0 bit,and the unused bit is always 0. These two bits are not given because they are the most significant bits, andleading zeros are often omitted.FTOS#show interface tengig 1/21TenGigabitEthernet 1/21 is up, line protocol is upHardware is Dell Force10Eth, address is 00:01:e8:0d:b7:4eCurrent address is 00:01:e8:0d:b7:4eInterface index is 72925242[output omitted]Card TypeInterface TypePort NumberSlot Number14 bits4 bits7 bits1 bitUnused5 bits1 bitP/L Flag
