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Thread: Who is your ISP?

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  1. #1
    Join Date
    Feb 2010
    Posts
    235

    Default Re: Who is your ISP?

    Motorola SB5100 cable modem. Works fine.
    Address 192.168.100.1 yields displays from modem. One is signal conditions. Watching this over time will tell you if things go marginal due to a flakey coax or system problems on their side. Also compare to neighbors'.

    My good norms are
    downstream signal strength -8 dBm plus or minus 6. More negative is bad.
    upstream signal 40dBm plus or minus 5. More positive is bad. This is the one to watch closely. If it gets into the 50s, you've got a flakey coax somewhere, or they do. Their cable system head-end controls the upstream signal strength - it asks for a stronger signal if their end is a weak signal. The downstream is uncontrolled- just affected by your coax/splitters and their offered signal.

    The upstream is low frequency. The downstream is high. So a break or poor connection in the center conductor of the coax somewhere will affect the upstream more than the downstream.

    There should be one 2-way splitter between your cable modem and the main coax entering the house. And that should be ahead of any whole-house amps you have.

    A well trained (few are) tech from the cable co. should know all this and check it all. Even if they have to be pushed and prodded to crawl in the attic or under the house. Replace coax while there, just in case.
    Last edited by stevech; 04-30-2010 at 09:28 PM.

  2. #2
    Join Date
    Feb 2007
    Location
    Kitsap County, WA.
    Posts
    734

    Default Re: Who is your ISP?

    Quote Originally Posted by stevech View Post
    Motorola SB5100 cable modem. Works fine.

    My good norms are
    downstream signal strength -8 dBm plus or minus 6. More negative is bad.
    upstream signal 40dBm plus or minus 5. More positive is bad.
    OdBmV is a better goal for downstream technically but your downstream SNR is also a pretty important number...

    I always tell my clients to do three ping tests for me when troubleshooting...

    ping the modem c:>ping -n 100 192.168.100.1 wiggle all your ethernet connections. Should be 1-2ms

    Ping the modems gateway. c:>ping -n 50 <ISP Gateway> wiggle your rf connections and watch the screen... See if the wiggling affects anything...10-20ms avg. depending on system load. Anymore your area may be oversold...

    Ping something far out there... use -n 50 there also and post em all.
    20-80ms avg. in the nation.

    If your signal levels are causing you issues, you will have packet loss between your modem and the gateway. But it doesn't matter if your not getting the packet loss. Your ISP is supposed to keep you within DOCSIS specs.

    Look here for recommended signal levels. http://www.dslreports.com/faq/5862 Notice the difference between DOCSIS standards and the recommended levels. My ISP was tighter until they needed to cut costs...

    Look for issues throughout temperature swings that might affect your levels.

    Keep in mind that the RF is generated from the nodes on the poles or shelters in you neighborhood. Brought there via fiber. Unless you live next to the cable co offices...

    Last edited by chpalmer; 04-30-2010 at 10:26 PM.
    I Void Warranties.

  3. #3

    Default Re: Who is your ISP?

    Quote Originally Posted by stevech View Post
    Motorola SB5100 cable modem. Works fine.
    Address 192.168.100.1 yields displays from modem. One is signal conditions. Watching this over time will tell you if things go marginal due to a flakey coax or system problems on their side. Also compare to neighbors'.
    My signals are always -6 dBmV down, 39 dBmV up and 37-39 SNR. I doubt my signal is the problem. So far since I moved the ATA behind DD-WRT, there have been no problems. It makes no sense to me, but I'll update if we see any more anomalies.

    Edit: To add, my pings to modem are 3.5ms solid, 8.5ms to the modem gateway and 25ms to Google's DNS servers.
    Last edited by energyx; 05-01-2010 at 07:12 AM.

  4. #4
    Join Date
    Feb 2007
    Location
    Kitsap County, WA.
    Posts
    734

    Default Re: Who is your ISP?

    Edit: To add, my pings to modem are 3.5ms solid, 8.5ms to the modem gateway and 25ms to Google's DNS servers.
    Nothing wrong with that at all. Id be a little concerned with the 3.5ms to your modem if I was a gamer... Rule out the router by going direct and testing if ping times matter. Your modem just may be slower to respond to pings. But the 8.5ms to your ISP is something to be jealous of. This would mean that if you truly have 3.5ms of latency to your modem then your gateway is only 5ms away...

    If you have intermittent problems, watch it throughout the day.

    When you went from your ata at the modem to the DD-WRT at the modem, you would have been assigned a new public IP address. Probably on a new gateway at your ISP. The other gateway could of had issues.

    When my ISP was in its infancy, they had everything running from Windows boxes at the headend. The load balancing sucked and a small number of us were getting pretty good at using cloned MAC addresses from other computers on our own networks into our routers to get our gateway ip to change. We would actually get on DSLR and share the gateway info we were having success with. Not to say for sure this is your issue but you never know...


    Pinging 192.168.100.1 with 32 bytes of data:

    Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
    Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
    Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
    Reply from 192.168.100.1: bytes=32 time=1ms TTL=63
    I Void Warranties.

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