Internet very slow

Unanswered Question
Mar 1st, 2010

4Mbps Bandwidth of Internet is provided to my company by the ISP. When I check the speed of the internet at the inside interface of the Juniper firewall I get around 3.4 Mbps. The Juniper is connected to two Catalyst 4507 Core switches, which is then connected to 3560 Access Switches. The users connected to the Access Switch only gets an internet speed of 500kbps. The drop seems to be happening at the Core Switches. How can I verify and determine what is causing this slow speed??

Thanks in Advance.

I have this problem too.
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jennyjohn Mon, 03/01/2010 - 04:39

behind the Juniper firewall I am getting good internet speed (nearly 3.4 Mbps). The Core Switches and the Access Switches stand between the user and the Juniper firewall, forcing me to believe that they are the cause.

Kevin Dorrell Mon, 03/01/2010 - 04:50

How are you measuring the speed at the access switch?.  There are many factors that can affect the throughput: PC performance, access link speed and duplex, etc..  Also, be aware that Windows displays speed in bytes per second.

Kevin Dorrell


jennyjohn Mon, 03/01/2010 - 05:00

I am using websites like to check the speed of the internet.

Kevin Dorrell Mon, 03/01/2010 - 05:22

Cool site!  Is it both directions, upload and download, that are suffering behind the access switch, or one direction only?

Also, have you checked the speed and duplex arrangements between the PCs and the access switch.  Do you use fixed duplex or auto?  If it is auto, it needs to be auto on both the switchport and the PC.  If it is fixed, then it needs to be fixed on both the switchport and the PC.

Perhaps you could port a show int for one of the PC ports on the access switch?

Kevin Dorrell


jennyjohn Mon, 03/01/2010 - 22:26

The Download speed is only affected, the upload is nearly 3.4 Mbps

The duplex and speed are all set to auto.

This is an interface on the access switch to which a PC is connected.

Fourth-Floor1#show  interfaces fastEthernet 0/13
FastEthernet0/13 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 000f.8f54.690d (bia 000f.8f54.690d)
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is 100BaseTX
  input flow-control is unsupported output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, 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
     14193289 packets input, 2342317097 bytes, 0 no buffer
     Received 23510 broadcasts (0 multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 866 multicast, 0 pause input
     0 input packets with dribble condition detected
     84208247 packets output, 1325629454 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


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