7 Replies Latest reply: Feb 23, 2013 9:47 PM by Mahdi RSS

    Packet loss

    imatiger1

      hello,

      i have two catalyst (C1 & C2) wich are directly connected via fiber. Machine A is connected to Switch C1 and Machine B is connected to Switch C2.

      The problem is that Machine A and B detect that there is some packets drops. when i see input and output queues (show interface Gix/x) on input/output interfaces of switches C1 & C2 couters are set to 0 (there is no drop) ?

      i'm really confused !! have an idea of the root cause ?

      thanks

       

      ima

        • 1. Re: Packet loss
          Martin

          what are Machine A and B ?  PC or server?

          • 2. Re: Packet loss
            Sey

            How do A & B detect packet drops? Can you show the topology and "show interface" of the interfaces in question?

            • 3. Re: Packet loss
              Mahdi

              When your packet drops on switches shows 0, it simply means that your called machine A or B, are busy in responsing. try to see their process in windows via task manager or in linux via top command.

               

              HTH

              Mahdi

              • 4. Re: Packet loss
                imatiger1

                hello,

                 

                it is a multicast flow. end user have specific application which allow them to detect packet loss.

                 

                Drawing1.png

                 

                Please find following the output of interfaces on Switch C1. here are the same on Switch C2.

                 

                C1#sh interfaces TenGigabitEthernet 1/49

                TenGigabitEthernet1/52 is up, line protocol is up (connected)

                  Hardware is Ten Gigabit Ethernet Port, address is c89c.1d68.69ff (bia c89c.1d68.69ff)

                  Description: " To C2 "

                  Internet address is 192.168.20.1/30

                  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

                     reliability 255/255, txload 1/255, rxload 1/255

                  Encapsulation ARPA, loopback not set

                  Keepalive set (10 sec)

                  Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX

                  input flow-control is on, output flow-control is off

                  ARP type: ARPA, ARP Timeout 04:00:00

                  Last input 00:00:00, 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

                  Queueing strategy: fifo

                  Output queue: 0/40 (size/max)

                  30 second input rate 7070000 bits/sec, 7388 packets/sec

                  30 second output rate 295000 bits/sec, 374 packets/sec

                  L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

                  L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

                  IPv6 L3 in Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

                  IPv6 L3 out Switched: ucast: 0 pkt, 0 bytes - mcast: 0 pkt, 0 bytes

                     30421678188 packets input, 3780710966119 bytes, 0 no buffer

                     Received 29758993452 broadcasts (43300 IP multicasts)

                     2 runts, 0 giants, 0 throttles

                     3 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored

                     0 input packets with dribble condition detected

                     1067967422 packets output, 116887814270 bytes, 0 underruns

                     0 output errors, 0 collisions, 5 interface resets

                     0 babbles, 0 late collision, 0 deferred

                     0 lost carrier, 0 no carrier

                     0 output buffer failures, 0 output buffers swapped out

                 

                 

                C1#sh interfaces TenGigabitEthernet 1/50

                TenGigabitEthernet1/49 is up, line protocol is up (connected)

                  Hardware is Ten Gigabit Ethernet Port, address is c89c.1d68.69f0 (bia c89c.1d68.69f0)

                  Description: " To A "

                  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

                     reliability 255/255, txload 1/255, rxload 2/255

                  Encapsulation ARPA, loopback not set

                  Keepalive set (10 sec)

                  Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX

                  input flow-control is on, output flow-control is off

                  ARP type: ARPA, ARP Timeout 04:00:00

                  Last input 00:00:11, output never, output hang never

                  Last clearing of "show interface" counters never

                  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0

                  Queueing strategy: fifo

                  Output queue: 0/40 (size/max)

                  5 minute input rate 7964000 bits/sec, 2930 packets/sec

                  5 minute output rate 6358000 bits/sec, 2114 packets/sec

                     9669075070 packets input, 1653112430890 bytes, 0 no buffer

                     Received 9112272279 broadcasts (522181486 multicasts)

                     0 runts, 0 giants, 0 throttles

                     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

                     0 input packets with dribble condition detected

                     7368777064 packets output, 1287973446345 bytes, 0 underruns

                     0 output errors, 0 collisions, 0 interface resets

                     0 babbles, 0 late collision, 0 deferred

                     0 lost carrier, 0 no carrier

                     0 output buffer failures, 0 output buffers swapped out

                • 5. Re: Packet loss
                  Mahdi

                  You C1 output shows you have error !

                  Does your cabel support 10 G ? the output shows the media is 1000Mb/s but your interfaces are 10G. if you cannot change cable use speed command to change interface speed to 1G.

                   

                  HTH

                  Mahdi

                  • 6. Re: Packet loss
                    imatiger1

                    hello mahdi,

                    Errors don't concerns this case. these are old errors because i don't clear my interface counters.

                    interfaces speed are set to 1G.

                    • 7. Re: Packet loss
                      Mahdi

                      Are all of your connections work on 1G ? I mean  between your servers and switches and between switches. if they are ok and the load on your server is not high, it will be related to one of following :

                      1. Your multicast misconfiguration

                      2. Your servers interface driver

                       

                      HTH

                      Mahdi