Port Interface Index

To determine the interface index (IfIndex), you can calculate it, or use the CLI command provided in this section.

As a result of channelization support, the IfIndex of each channelization–capable port increases by 4. The number is reserved for the 3 sub-ports when channelization is enabled.

5320 Series, 5420 Series, 5520 Series, and 5720 Series

For switches that include channelization-capable ports, use the following equations to determine the IfIndex of a port:

If the port does not support channelization, use (64 x slot number) +128 + (port number -1).
If the port supports channelization, use the following equations:
- for the port in question: (64 x slot number) +128
- for subsequent ports: (64 x slot number) +128 + ((port number -1) *4)
  
  This equation reserves space for the creation of the 3 sub-ports on the previous port, if or when you enable channelization.

The slot number is 1 for the 5320 Series.

The slot numbers are 1-2 for the 5420 Series.

The slot numbers are 1-2 for the 5520 Series.

The slot numbers are 1-2 for the 5720 Series.

CLI command

To determine the port interface index through the CLI, use the following command:

show interfaces gigabitEthernet

The following example shows output for this command:

Switch:1(config)#show interfaces gigabitEthernet 

==========================================================================================
                                      Port Interface
==========================================================================================
PORT                            LINK  PORT           PHYSICAL          STATUS
NUM      INDEX DESCRIPTION      TRAP  LOCK     MTU   ADDRESS           ADMIN  OPERATE
------------------------------------------------------------------------------------------
1/1      192   1000BaseTX          true  false    1950  f0:64:26:70:f8:00 up     up
1/2      193   1000BaseTX          true  false    1950  f0:64:26:70:f8:01 up     down
1/3      194   1000BaseTX          true  false    1950  f0:64:26:70:f8:02 up     down
1/4      195   1000BaseTX          true  false    1950  f0:64:26:70:f8:03 up     down
1/5      196   1000BaseTX          true  false    1950  f0:64:26:70:f8:04 up     down
1/6      197   1000BaseTX          true  false    1950  f0:64:26:70:f8:05 up     down
1/7      198   1000BaseTX          true  false    1950  f0:64:26:70:f8:06 up     down
1/8      199   1000BaseTX          true  false    1950  f0:64:26:70:f8:07 up     down
1/9      200   1000BaseTX          true  false    1950  f0:64:26:70:f8:08 up     down
1/10     201   1000BaseTX          true  false    1950  f0:64:26:70:f8:09 up     down
1/11     202   1000BaseTX          true  false    1950  f0:64:26:70:f8:0a up     down
1/12     203   1000BaseTX          true  false    1950  f0:64:26:70:f8:0b up     down
1/13     204   1000BaseTX          true  false    1950  f0:64:26:70:f8:0c up     down
--More-- (q = quit)