Results 1 to 4 of 4

Peculiar latency problem when changing dns servers

  1. #1
    Silver Member
    Join Date
    Feb 2009
    Posts
    318

    Default Peculiar latency problem when changing dns servers

    For the last 2 weeks I have had a very strange problem with latencies when I use google/reliance dns.

    Usually; say I start off with a 290ms latency to a certain server.
    After about an hour - maybe less or more; Slowly this latency will increase by about 100ms to say 370-390ms.

    When this happens there is a noticeable lag.
    Eventually there is even some packet loss.

    Then I repeatedly switch between different dns servers; or simply reconnect to the same connection and the problem goes back to square one.

    Code:
    Reply from 66.199.244.82: bytes=32 time=368ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=365ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=372ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=367ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=374ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=369ms TTL=52
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 66.199.244.82: bytes=32 time=370ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=370ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=370ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=367ms TTL=52
    Reply from 66.199.244.82: bytes=32 time=368ms TTL=52
    Request timed out.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 192.168.1.1: Destination net unreachable.
    Reply from 66.199.244.82: bytes=32 time=313ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=286ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=287ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=292ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=285ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=294ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=285ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=288ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=286ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=292ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=286ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=286ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=287ms TTL=50
    Reply from 66.199.244.82: bytes=32 time=288ms TTL=50
    In the above I try to reconnect twice and then the latency goes back to normal.

    This seems to happen throughout the day and to almost any server -
    After any variable length of time - anywhere between 15 minutes an 1 hour; latency will slowly creep up to 100-150ms above normal.

    Then I try connecting and reconnecting my internet with dialers using different DNS addresses.

    Eventually after 4-5 attempts 1 connection will be established with normal latency.

    Again after some time the problem repeats itself.

    All of this doesn't seem to have much of a correlation on whether or not I'm downloading or torrenting anything.

    I have used namebench to pick a good dns server and each time it changes. Regardless I have set up dialers for each of these servers; but the problem crops up in all of them.

    1 more thing whenever the latency goes up like this my internet browsing speed goes down significantly with webpages often getting stuck loading.

  2. #2
    Amor vincit omnia
    Join Date
    Dec 2007
    Posts
    3,141

    Default

    The problem cropping up after a certain time period often points out to be routing issue. Perhaps BSNL redirects the traffic to the desired server via a congested route.

    This is an assumption - may / may not be the effective explanation to what you are facing..
    Last edited by cool_techie_tvm; 25th October 2011 at 08:43 AM. Reason: spelin

  3. #3
    Silver Member
    Join Date
    Feb 2009
    Posts
    318

    Default

    Probably yeah, it's just that it happens ever 20 minutes or so to *all* servers in the EU and US.

    Sometimes reconnecting to bsnl repeatedly fixes the problem; but often it doesn't.

    Also the problem wasn't happening last month.

    traceroute to Product reviews and prices, software downloads, and tech news - CNET
    Code:
    Tracing route to phx1-rb-gtm1-tron-xw-lb.cnet.com [64.30.224.103]
    over a maximum of 30 hops:
      1    12 ms    11 ms    11 ms  59.93.192.1
      2    53 ms    51 ms    53 ms  218.248.255.42
      3    47 ms    47 ms    47 ms  59.163.201.153.static.chennai.vsnl.net.in [59.163.201.153]
      4    70 ms    69 ms    71 ms  172.31.16.173
      5    71 ms    71 ms    75 ms  if-0-100.tcore2.MLV-Mumbai.as6453.net [180.87.39.25]
      6   334 ms   333 ms   333 ms  if-6-2.tcore1.L78-London.as6453.net [80.231.130.5]
      7   346 ms   341 ms   343 ms  Vlan704.icore1.LDN-London.as6453.net [80.231.130.10]
      8   380 ms   379 ms   379 ms  Vlan533.icore1.LDN-London.as6453.net [195.219.83.102]
      9   380 ms   379 ms   379 ms  ae-52-52.csw2.London1.Level3.net [4.69.139.120]
     10   385 ms   379 ms   379 ms  ae-56-221.ebr2.London1.Level3.net [4.69.153.129]
     11   379 ms   379 ms   379 ms  ae-42-42.ebr1.NewYork1.Level3.net [4.69.137.70]
     12   382 ms   385 ms   383 ms  ae-10-10.ebr2.Washington12.Level3.net [4.69.148.50]
     13   382 ms   385 ms   383 ms  ae-1-100.ebr1.Washington12.Level3.net [4.69.143.213]
     14   394 ms   397 ms   397 ms  ae-6-6.ebr1.Atlanta2.Level3.net [4.69.148.105]
     15   396 ms   395 ms   397 ms  ae-63-63.ebr3.Atlanta2.Level3.net [4.69.148.241]
     16   418 ms   417 ms   417 ms  ae-7-7.ebr3.Dallas1.Level3.net [4.69.134.21]
     17   422 ms   421 ms   421 ms  ae-63-63.csw1.Dallas1.Level3.net [4.69.151.133]
     18   422 ms   421 ms   421 ms  ae-61-61.ebr1.Dallas1.Level3.net [4.69.151.126]
     19   450 ms   449 ms   449 ms  ae-1-8.bar1.Phoenix1.Level3.net [4.69.133.29]
     20   449 ms   449 ms   449 ms  ae-0-11.bar2.Phoenix1.Level3.net [4.69.148.114]
     21   460 ms   461 ms   461 ms  ae-5-5.car2.Phoenix1.Level3.net [4.69.148.121]
     22   460 ms   461 ms   461 ms  CBS-CORPORA.car2.Phoenix1.Level3.net [4.53.106.146]
     23   452 ms   451 ms   451 ms  64.30.227.118
     24   448 ms   451 ms   449 ms  phx1-rb-gtm1-tron-xw-lb.cnet.com [64.30.224.103]
    
    Trace complete.
    server in new jersey, usa
    Last edited by rsen; 25th October 2011 at 08:23 AM. Reason: Automerged Doublepost

  4. #4
    Amor vincit omnia
    Join Date
    Dec 2007
    Posts
    3,141

    Default

    Here is the traceroute report for the same domain from airtel BB



    Clearly the hop count while using BSNL and Airtel becomes different - perhaps this is the cause of the your latency problem..

Similar Threads

  1. Bsnl broadband latency to EU and UK servers
    By terminatorr5 in forum BSNL broadband
    Replies: 1
    Last Post: 13th April 2013, 12:59 PM
  2. High latency in us servers...
    By Thingone in forum Airtel Broadband
    Replies: 1
    Last Post: 5th October 2011, 04:43 PM
  3. Latency issues to servers in Western US and Canada
    By rsen in forum BSNL broadband
    Replies: 0
    Last Post: 1st May 2010, 06:25 AM
  4. Replies: 4
    Last Post: 29th January 2010, 09:22 PM
  5. Same city but different Latency on servers
    By nilaynashikkar in forum BSNL broadband
    Replies: 3
    Last Post: 20th February 2009, 09:56 PM