5 Replies Latest reply: May 24, 2009 4:28 AM by Krzysztof Przybylski RSS

    Cisco_c7:c9:82     LOOP     Reply- Clarity

    Miizarebel CCNP/CCDP/CCNP Wireless/CWDP/CWNA

      Hello everyone,

       

      I am using wireshark to capture OSPF traffic i see the following loop reply:

       

       

      9    6.131242    Cisco_c7:c9:82    Cisco_c7:c9:82    LOOP    Reply

       

      Can somone please clarify the output above?

       

      Thanks

        • 1. Re: Cisco_c7:c9:82     LOOP     Reply- Clarity
          Krzysztof Przybylski

          Hi !

           

          You could add  more info

          for example that:

           

          - this traffic is on Ethernet interface

          - it is send every 10 sec.

           

           

          It is a normal situation, because its a keepalive

          Device is checking / testing itself

           

           

           

          - Krzysztof Przybylski

          • 2. Re: Cisco_c7:c9:82     LOOP     Reply- Clarity
            Conwyn

            Hi Miizarebel and Krzysztof

             

            Here is a ospf packet debug of two routers connect by a serial and the packets are every 10 seconds.

            Do we know what is Cisco_C7:C9:82 in the title? It looks like a LAT name generated when the hostname is > 16 characters

             

            r1#debug ip ospf packet
            OSPF packet debugging is on
            r1#
            *Mar  1 00:01:56.967: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:06.963: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:16.955: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:26.967: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:36.975: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:46.963: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            *Mar  1 00:02:56.979: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0
            r1#no debug
            *Mar  1 00:03:06.963: OSPF: rcv. v:2 t:1 l:48 rid:10.0.0.1
                  aid:0.0.0.0 chk:D79B aut:0 auk: from Serial1/0all
            All possible debugging has been turned off

             

            A later debug of ip

            r1#debug ip packet detail
            IP packet debugging is on (detailed)
            r1#
            *Mar  1 00:17:06.983: IP: s=10.0.0.1 (Serial1/0), d=224.0.0.5, len 80, rcvd 0, p
            roto=89
            *Mar  1 00:17:10.707: IP: s=10.0.0.2 (local), d=224.0.0.5 (Serial1/0), len 80, s
            ending broad/multicast, proto=89
            *Mar  1 00:17:16.959: IP: s=10.0.0.1 (Serial1/0), d=224.0.0.5, len 80, rcvd 0, p
            roto=89
            r1#no de
            *Mar  1 00:17:20.707: IP: s=10.0.0.2 (local), d=224.0.0.5 (Serial1/0), len 80, s
            ending broad/multicast, proto=89bug all
            All possible debugging has been turned off
            r1#debug ip packet dump
            IP packet debugging is on (dump)
            r1#
            *Mar  1 00:17:36.967: IP: s=10.0.0.1 (Serial1/0), d=224.0.0.5, len 80, rcvd 0
            0F401750:          0F000800 45C00050 006C0000      ....E@.P.l..
            0F401760: 0159CE23 0A000001 E0000005 02010030  .YN#....`......0
            0F401770: 0A000001 00000000 D79B0000 00000000  ........W.......
            0F401780: 00000000 FFFFFFFC 000A1201 00000028  .......|.......(
            0F401790: 00000000 00000000 0A000002 FFF60003  .............v..
            0F4017A0: 00010004 00000001                    ........
            *Mar  1 00:17:40.707: IP: s=10.0.0.2 (local), d=224.0.0.5 (Serial1/0), len 80, s
            ending broad/multicast
            0F401890:                   45C00050 00680000          E@.P.h..
            0F4018A0: 0159CE26 0A000002 E0000005 02010030  .YN&....`......0
            0F4018B0: 0A000002 00000000 D8970000 00000000  ........X.......
            0F4018C0: 00000000 FFFFFF00 000A1201 00000028  ...............(
            0F4018D0: 00000000 00000000 0A000001 FFF60003  .............v..
            0F4018E0: 00010004 00000001                    ........
            *Mar  1 00:17:46.967: IP: s=10.0.0.1 (Serial1/0), d=224.0.0.5, len 80, rcvd 0
            0F401C50:          0F000800 45C00050 006D0000      ....E@.P.m..
            0F401C60: 0159CE22 0A000001 E0000005 02010030  .YN"....`......0
            0F401C70: 0A000001 00000000 D79B0000 00000000  ........W.......
            0F401C80: 00000000 FFFFFFFC 000A1201 00000028  .......|.......(
            0F401C90: 00000000 00000000 0A000002 FFF60003  .............v..
            0F401CA0: 00010004 00000001                    ........        no debug al
            *Mar  1 00:17:50.707: IP: s=10.0.0.2 (local), d=224.0.0.5 (Serial1/0), len 80, s
            ending broad/multicast
            0F401D90:                   45C00050 00690000          E@.P.i..
            0F401DA0: 0159CE25 0A000002 E0000005 02010030  .YN%....`......0
            0F401DB0: 0A000002 00000000 D8970000 00000000  ........X.......
            0F401DC0: 00000000 FFFFFF00 000A1201 00000028  ...............(
            0F401DD0: 00000000 00000000 0A000001 FFF60003  .............v..
            0F401DE0: 00010004 00000001                    ........        l
            All possible debugging has been turned off
            r1#

            • 3. Re: Cisco_c7:c9:82     LOOP     Reply- Clarity
              Krzysztof Przybylski

              Hello Conwyn,

               

              I hope I understand you right,

              In my opinion "Cisco_C7:C9:82" (precisely C7:C9:82 part) is a MAC address of the Ethernet interface.

              And like I said before, this message is simply Ethernet Cisco keepalive.

              On serial interface there is no such thing like above loop reply 'keepalive' example.

               

               

              - Krzysztof

              • 4. Re: Cisco_c7:c9:82     LOOP     Reply- Clarity
                Conwyn

                Hi Krzysztof

                 

                My apolgies since the question referred to OSPF I assumed the wireshark reference also concerned OSPF packets. As you can see OSPF is also transmitting those packets every 10 seconds. I was thinking about the convention before I saw your post and I wondered if Wireshark had identified the manufacturer identification within the Ethernet and displayed CISCO and then the specific element of the Ethernet frame. When the thread lacks specific detail it is always a dilema whether to guess and try to answer or whether to request more information and given the different timezones of the CLN the answering of a question can take days.

                 

                Regards Conwyn

                • 5. Re: Cisco_c7:c9:82     LOOP     Reply- Clarity
                  Krzysztof Przybylski

                  You are absolutely right

                  Sometimes when problem seems very complicated, the solution is very simple

                   

                  pozdrawiam

                  greetings

                   

                  Krzysztof