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Highlighted
Explorer

Slow connection, could someone help me understand this int output...

I have a router that serves the connection to the Internet for 3 different areas. Users are getting a really slow connection and I'm trying to make sense of this interface that connects to the internet. The Internet line is supposed to be capable of 30Mbits a second.

According to this output is this interface receiving 5869000 bits (5.6Mbits) of data a second and only outputting at a rate of 1221000 bits (1.2Mbit) a second? If the connection is indeed 30Mbit a second should it be outputting closer to 31457280 bit (30Mbits) a second?

GigabitEthernet0/1 is up, line protocol is up

  Hardware is __ Ethernet, address is ****.****.****

  Internet address is 192.168.1.1/24

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

     reliability 254/255, txload 1/255, rxload 1/255

  Encapsulation ARPA, loopback not set

  Keepalive set (10 sec)

  Full-duplex, 1000Mb/s, media type is T

  output flow-control is XON, input flow-control is XON

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

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

  Last clearing of "show interface" counters never

  Input queue: 51/75/11032859/0 (size/max/drops/flushes); Total output drops: 0

  Queueing strategy: fifo

  Output queue: 0/40 (size/max)

  5 minute input rate 5869000 bits/sec, 1009 packets/sec

  5 minute output rate 1221000 bits/sec, 502 packets/sec

     596933819 packets input, 2456331000 bytes, 2628 no buffer

     Received 7266 broadcasts, 0 runts, 0 giants, 1021276 throttles

     15354216 input errors, 0 CRC, 0 frame, 37417 overrun, 15316799 ignored

     0 watchdog, 0 multicast, 0 pause input

     0 input packets with dribble condition detected

     1820839956 packets output, 1477679970 bytes, 0 underruns

     0 output errors, 0 collisions, 0 interface resets

     0 unknown protocol drops

     0 unknown protocol drops

     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

6 REPLIES 6
Highlighted
Rising star

First thing, log onto this router and do a clear counters. then check 12 ore 24 hours later to see if the input errors overrun and ignored have increased. we cant tell from this how old the data is.

you might consider posting this routers config (with all confidential info removed)

Highlighted
Participant

hello Mark,

I will be more worried about reliability 254/255, txload 1/255, rxload 1/255

It suppose to be always reliability 255/255 so please check cables and replace them and try again same command.

We was having same issue with our core and changing cable fix the issue.

please rate if this helps

thanks

Highlighted
VIP Expert

Disclaimer

The   Author of this posting offers the information contained within this   posting without consideration and with the reader's understanding that   there's no implied or expressed suitability or fitness for any purpose.   Information provided is for informational purposes only and should not   be construed as rendering professional advice of any kind. Usage of  this  posting's information is solely at reader's own risk.

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Posting

Your input errors to received packets ratio is high enough it can be detrimental. This might be a contributing factor to your poor perceived performance.

Your snapshot stats also show a deep (51) input queue (generally unusual) and many input queue drops.  You might be able to reduce your input queue drops by expanding the input queue's depth, but this should be further investigated.

I see the connection is physically gig although note link supports 30 Mbps transfer rate.  What's the device?

If this is a low end router, you might also improve the situation by running g0/1 interface at 100 Mbps.

PS:

Some input queue and Ethernet interface Cisco documentation:

http://www.cisco.com/en/US/products/hw/modules/ps2643/products_tech_note09186a0080094a8c.shtml

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a0080094791.shtml#topic2

http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1904.html#wp1020879

http://www.cisco.com/en/US/products/hw/routers/ps167/products_tech_note09186a008012fb87.shtml

Highlighted
Explorer

Thank you for the responses.

Amrinder, I will definately look into the wiring being the potential cause but the same issue also occurs else where at random times so I'm not sure if that will be the issue.

Joseph, Thanks for those links, they helped me undertsand this output a lot more. I'm not sure how to determine what's at the other end of the 30Mbit connection. You mentioned about changing the interface speed to 100Mbps, would this be done by using the "bandwidth 100000" command? I read in the link you sent me that lowering the speed could help prevent packets being put in queue. Would the txrate and rxrate be more accurate by lowering the speed as well?

Thanks for the help!

Highlighted

  what do you plug your ethernet cable into?

What model is the device you are using for this link? aswitch or a router ?

Highlighted

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

You mentioned about changing the interface speed to 100Mbps, would this be done by using the "bandwidth 100000" command? I read in the link you sent me that lowering the speed could help prevent packets being put in queue. Would the txrate and rxrate be more accurate by lowering the speed as well?

No, by lowering the speed, I meant running the physical link at 100 Mbps rather than 1 Gbps.  This allows the router 10x the time to process back-to-back packets.  Since you're logical cap is 30 Mbps, it shouldn't be too adverse to total throughput.

The tx and rx rates tend to be accurate, but by default, they're a 5 minute average.  Setting the load-interval to the minimum, 30 seconds, will have them more closely track real-time performance, but on networks, with FastEthernet or faster interfaces, a lot can happen in 30 seconds.

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