3 Replies Latest reply: Apr 8, 2010 9:18 AM by Patrick Lao RSS

    What is the function of Interface NVI0 in NAT?


      Hello everyone,


      By issuing the command ip nat inside on a fastethernet interface i got this result:


      *Mar  1 01:09:14.867: %LINEPROTO-5-UPDOWN: Line protocol on Interface NVI0, changed state to up




      router#sh interfaces


      NVI0 is up, line protocol is up
        Hardware is NVI
        Interface is unnumbered. Using address of FastEthernet0/0 (
        MTU 1514 bytes, BW 10000000 Kbit, DLY 0 usec,
           reliability 255/255, txload 1/255, rxload 1/255
        Encapsulation UNKNOWN, loopback not set
        Last input never, output never, output hang never
        Last clearing of "show interface" counters never
        Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
        5 minute input rate 0 bits/sec, 0 packets/sec
        5 minute output rate 0 bits/sec, 0 packets/sec
           0 packets input, 0 bytes, 0 no buffer
           Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
           0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
           0 packets output, 0 bytes, 0 underruns
           0 output errors, 0 collisions, 0 interface resets
           0 output buffer failures, 0 output buffers swapped out


      Just curious, what does this NVIO interface do? It's not really mentioned on the NAT theory. The links i've read so far are a bit vague on the subject.


      Maybe someone can elaborate more?


      IOS on the router C3725-ADVENTERPRISEK9-M