Results 1 to 7 of 7

Thread: Cable Modem Losing Connection

  1. #1
    Junior Member
    Join Date
    Aug 2003
    Location
    Canada
    Posts
    1

    Cable Modem Losing Connection

    I have recently encountered a problem with a Doxport 111 Cable Modem that indicates a loss of a cable connection. Data transfer will naturally stop, cable indicator light will blink...for about a minute or two.

    I have checked all physical connections which seem to be good. I suspect that the modem, (which is about three years old), is beginning to pack it in, although I can't be sure.

    My ISP reports they see a good connection....(yeah right).

    Oh yeah, I have the TCP/IP Protocol set manually as opposed to automatic function. When the cable modem is working I have a good connection.

    Any suggestions?

  2. #2
    Regular Member buckifan's Avatar
    Join Date
    Jan 2004
    Location
    Buckeye Nation
    Posts
    133
    I don't think the Doxport 111 has a diagnostic page but give it a try anyway.

    http://192.168.100.1/

    Before you throw it out I'd have a tech come out and check your signal levels. You might have a chewed up drop or something else that is affecting the signal.

  3. #3
    Junior Member
    Join Date
    Apr 2006
    Posts
    1
    Same exact problem with a Motorola Surfboard - Cable Co says good signal, etc and no problem. Meanwhile the modem drops it's connection several times per day. Daignostics read:
    060416132552 7-Information Synchronization LOST <705000000 Hz - ucd 1, Station Maintenance T4 Timeout or Ranging ABORT>
    060416132552 3-Critical R04.0 Received Response to Broadcast Maintenance Request, but no Unicast Maintenance opportunities received - T4 timeout
    060416125659 3-Critical R02.0 No Ranging Response received - T3 time-out
    060416121628 3-Critical R02.0 No Ranging Response received - T3 time-out

    Any suggestions on what this means? Thanks

  4. #4
    Junior Member
    Join Date
    Apr 2006
    Posts
    4
    Quote Originally Posted by 444arrow
    Same exact problem with a Motorola Surfboard - Cable Co says good signal, etc and no problem. Meanwhile the modem drops it's connection several times per day. Daignostics read:
    060416132552 7-Information Synchronization LOST <705000000 Hz - ucd 1, Station Maintenance T4 Timeout or Ranging ABORT>
    060416132552 3-Critical R04.0 Received Response to Broadcast Maintenance Request, but no Unicast Maintenance opportunities received - T4 timeout
    060416125659 3-Critical R02.0 No Ranging Response received - T3 time-out
    060416121628 3-Critical R02.0 No Ranging Response received - T3 time-out

    Any suggestions on what this means? Thanks
    Post SNR levels under "signal" and up and down stream levels. Do you have a cable channel 109-110? That is very close to your downstream carrier, if the channel is weak (noisy) then your problem is ingress in that range.

  5. #5
    Junior Member
    Join Date
    Mar 2006
    Posts
    39
    also check for a splitter that is not up to 1000 mhz. you mave have on in your attic/crawl/basement that the cable guys missed.

  6. #6
    The Mad Scientist! Rocky_Grim's Avatar
    Join Date
    Feb 2003
    Location
    New Castle PA
    Posts
    351
    Check out the cable modem troubleshooting guide in my sig.

  7. #7
    Junior Member
    Join Date
    May 2006
    Posts
    1
    I'm getting the same problem with my Thomson TCM290
    Diagnostic data:
    Forward Path:
    Signal Acquired at 128.999 MHz
    SNR: 32.8 dB
    Received Signal Strength: -6.2 dBmV
    Micro-Reflections: 24 dBc
    Modulation: 256 QAM
    Return Path:
    Connection: Acquired
    Frequency: 23 MHz
    Power Level: 48.0 dBmV
    Channel ID: 3
    Modulation: QPSK
    What the tcp/ip analyzer told me
    TCP options string = 020405b40103030401010402
    MTU = 1500
    MTU is fully optimized for broadband.
    MSS = 1460
    Maximum useful data in each packet = 1460, which equals MSS.
    Default TCP Receive Window (RWIN) = 896000
    RWIN Scaling (RFC1323) = 4 bits (scale factor of 8)
    Unscaled TCP Receive Window = 56000

    For optimum performance, consider changing RWIN to a multiple of MSS.
    Other RWIN values that might work well with your current MTU/MSS:
    513920 (MSS x 44 * scale factor of 8)
    256960 (MSS x 44 * scale factor of 4)
    128480 (MSS x 44 * scale factor of 2)
    64240 (MSS x 44)
    bandwidth * delay product (Note this is not a speed test):

    Your TCP Window limits you to: 35840 kbps (4480 KBytes/s) @ 200ms
    Your TCP Window limits you to: 14336 kbps (1792 KBytes/s) @ 500ms
    MTU Discovery (RFC1191) = ON
    Time to live left = 54 hops
    TTL value is ok.
    Timestamps (RFC1323) = OFF
    Selective Acknowledgements (RFC2018) = ON
    IP type of service field (RFC1349) = 00000000 (0)
    Also I found THIS on Cisco's website
    If the upstream utilization is too high, or too many modems are connected to the same upstream, it is possible that some modems will not get the required bandwidth or transmit opportunities to fulfill their periodic ranging requirements, also resulting in a T4 timeout.
    Could the problem be in wrong bandwidth allocation on the ISP side? Maybe we should complain to them about it.

Similar Threads

  1. Cable Modem keeps dropping connection
    By Breakout in forum General Broadband Forum
    Replies: 17
    Last Post: 12-26-03, 10:23 PM
  2. Cable modem connection at 512kb/sec and i get 10kb/sec upload speeds.why?
    By peramioths26 in forum General Broadband Forum
    Replies: 7
    Last Post: 09-16-01, 03:21 PM
  3. Beld And Linksys And Toshiba Cable Modem
    By CampRyenWater in forum Networking Forum
    Replies: 0
    Last Post: 07-16-01, 04:56 PM
  4. Cable Modem and Ethernet card forget connection
    By MichaelConklin in forum General Broadband Forum
    Replies: 11
    Last Post: 02-09-01, 11:54 PM
  5. Switching cable modem connection
    By milwaukeeguy in forum General Broadband Forum
    Replies: 4
    Last Post: 12-08-00, 10:17 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •