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Strange issue with 2960S and Dell Server SLOW throughput.

Have a strange issue. I have 23 branches, all have a pair of 2960S switches running c2960s-universalk9-mz.122-55.SE5.bin

Each branch has a Dell server with a Broadcom NetXtreme Gigabit chipset.

When the server is set to auto/auto and switch set to auto/auto, switchport negotiates to gig/full.

When we do this, throughput between hosts on the same switch and the server is a measly 300-500KBps

As soon as I hard-set the server to 100/full (not the switch side yet), the switchport comes up as 100/half. Throughput jumps  up to 3-5 MBps

When I hard-set the switch side to 100/full to match the sever, I get FULL throughput between the server and clients on the same switch.

We've tried updating to latest drivers for the network card, but no dice. This is happening at EVERY branch, so i doubt its related to cabling. 


Any Ideas?


Hall of Fame Super Gold

When I hard-set the switch

When I hard-set the switch side to 100/full to match the sever, I get FULL throughput between the server and clients on the same switch.

Set your interface to "speed auto 100".  Check and make sure the ports don't have any collision errors using the command "sh controll e <PORT>".


I've verified the interface

I've verified the interface isn't showing any errors. Here's the outputs from the switch port where the server is. This particular one I'm not hard-setting the speed/duplex on either side, I'm using it as a test to determine if we can fix the issue.

Here's show interface and show controllers for the port.


MBO-SW#sh int gi1/0/40
GigabitEthernet1/0/40 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 10bd.18f8.cca8 (bia 10bd.18f8.cca8)
  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, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:02:26, output 00:00:01, 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)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 2000 bits/sec, 3 packets/sec
     42930725 packets input, 17169447873 bytes, 0 no buffer
     Received 902207 broadcasts (565191 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 565191 multicast, 0 pause input
     0 input packets with dribble condition detected
     105822728 packets output, 50063153917 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
MBO-SW#show control
MBO-SW#show controllers e
MBO-SW#show controllers ethernet-controller ?
  FastEthernet      FastEthernet IEEE 802.3
  GigabitEthernet   GigabitEthernet IEEE 802.3z
  down-when-looped  show state related to down-when-looped detection
  phy               show PHY registers
  port-asic         Show Port-ASIC info
  stack             show stack ports information
  |                 Output modifiers

MBO-SW#show controllers ethernet-controller gi1/0/40

     Transmit GigabitEthernet1/0/40           Receive
   2818528255 Bytes                       4284551153 Bytes
     52575681 Unicast frames                42028542 Unicast frames
     38095282 Multicast frames                565192 Multicast frames
     15151917 Broadcast frames                337016 Broadcast frames
            0 Too old frames              4177828967 Unicast bytes
            0 Deferred frames               67458170 Multicast bytes
            0 MTU exceeded frames           39264016 Broadcast bytes
            0 1 collision frames                   0 Alignment errors
            0 2 collision frames                   0 FCS errors
            0 3 collision frames                   0 Oversize frames
            0 4 collision frames                   0 Undersize frames
            0 5 collision frames                   0 Collision fragments
            0 6 collision frames
            0 7 collision frames            18613376 Minimum size frames
            0 8 collision frames             7899108 65 to 127 byte frames
            0 9 collision frames             4221021 128 to 255 byte frames
            0 10 collision frames            2308750 256 to 511 byte frames
            0 11 collision frames             728974 512 to 1023 byte frames
            0 12 collision frames            9159521 1024 to 1518 byte frames
            0 13 collision frames                  0 Overrun frames
            0 14 collision frames                  0 Pause frames
            0 15 collision frames
            0 Excessive collisions                 0 Symbol error frames
            0 Late collisions                      0 Invalid frames, too large
            0 VLAN discard frames                  0 Valid frames, too large
            0 Excess defer frames                  0 Invalid frames, too small
     14359543 64 byte frames                       0 Valid frames, too small
     49259877 127 byte frames
      8472563 255 byte frames                      0 Too old frames
      3308463 511 byte frames                      0 Valid oversize frames
       465850 1023 byte frames                     0 System FCS error frames
     29956584 1518 byte frames                     0 RxPortFifoFull drop frame
            0 Too large frames
            0 Good (1 coll) frames
            0 Good (>1 coll) frames

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