wrt54g wired stream gives dropouts, wireless not(!)

Discussion in 'Networking Issues' started by taj1, Dec 31, 2006.

  1. taj1

    taj1 LI Guru Member

    I have an old computer (P1, 32MB, Win98, Winamp, Realtek8139 ethernet card) that plays mp3 files from another computer (up-to-date laptop) without interruption, but only when that other computer is connected wireless to the router (wrt54g). When the other computer is connected to the wrt54g with ethernet cable, the mp3 files have dropouts every 5 seconds. I also get the same frequency of dropouts when the old computer is connected to a desktop computer (wired).

    Note: Everything works fine into the other direction.

    Router firmware: Both with Linksys 4.20 and Hyperwrt-Thibor-15c
    It does not matter if the other computer is running Windows or Linux, in both cases wireless works and wired does not.

    I expected wireless connections always to be slower and less reliable than wired. So I think that there is a hardware problem in wrt54g. What could be the reason and, more important, what could be the solution?
  2. Thibor

    Thibor Super Moderator Staff Member Member

    it's doubtful that it's the router. you should take a look at "TCP Optimiser", you'll find it in the downloads section under Network Utilities.
  3. Toxic

    Toxic Administrator Staff Member

    Have you tried the network card in a different PCI slot or update the drivers?
  4. taj1

    taj1 LI Guru Member

    Dear Thibor and Toxic,

    Thank you for your suggestions.
    As far as possible, I tried all options you suggested. Unfortunately without success. It only made me realise how dated Win98 is (cat and inf files that could not be found without help, hanging at some of the reboots, right now it is taking ages to go through another reboot).
    The card is a PCMCIA cardbus card, and only works in one slot. In the other one it blocks the system.
    TCP optimiser advised MTU 1500. It improved the situation a bit to 1 dropout every 10 sec or so, I also tried lowering to 1400, but that did not help, either. Is there anything else I could optimise? Maybe there is a workaround to increase the buffer or so?

    I am surprised that the network connection of the remote computer can influence the behaviour of the receiving system. This happens with 2 remote computers, so I guess that the remote machine's ethernet cards are not the cause. There is no problem between the remote systems, either.

    Edit: I tried 5 concurrent streams from the old computer to 2 other computers and the whole setup worked without a glitch. I guess that bandwidth is not the problem.
  5. jlowery7

    jlowery7 Network Guru Member

    Have you tried disabling the wireless on the other computer when you have the other computer hooked up with ethernet. In my exp. when Windows sees two different connections(i.e. you have the other computer hooked up to ethernet and the wireless is still active) then Windows has issues knowing which connection to use b/c the network addresses are the same and the subnets are the same. And when i say network address, i mean the network part of the ip address.
  6. taj1

    taj1 LI Guru Member

    Dear jlowery7

    Yes, I tried that but it did not help. The (other) desktop computer has no wireless connection at all, but still produces dropouts when I play mp3s on the old win98 computer. It works well into the other direction, though. I can maintain at least 2.5 MByte/s between the other computers so their speed seems not to be the issue for this.
    I removed as much software as possible from the win98 computer and that does not help, either.

    I just tested the following: I played a local mp3 on the old win98 computer, while downloading files from the (wired only) desktop computer. It worked better than playing an mp3 from the remote computer. I heard 1 hiccup per min. Now downloading from the wireless computer while playing a local mp3 gives a more hiccups.
    Network monitor tells a lot:
    mp3 playing from remote wired: ~15 kBytes/s --> not enough: dropouts
    mp3 playing from remote wireless: ~25 kBytes/s --> sufficient
    mp3 playing locally and downloading file from remote wired: ~23 kBytes/s
    mp3 playing locally and downloading file from remote wireless: ~250 kBytes/s
    Only downloading file from remote wired: ~300 kBytes/s
    Only downloading file from remote wireless: ~700 kBytes/s
    Internet radio works at least at 128 kb/s. Unfortunately I cannot monitor this, because win98 Network Monitor apparently only monitors MS (smb/samba) network traffic, and not all in/out network traffic :(

    Obviously the network traffic is putting pressure on the processor, and probably the network card is not the best, either, and therefore bandwidth is reduced, but the connections have enough capacity. It remains surprising that there is a such a huge difference between remote wired and wireless at all.
  7. .:slim:.

    .:slim:. LI Guru Member

    Might be a faulty CAT5 cable...you might want to try swapping your cable and see if your performance increases. I had a problem similar to that and it was the cable. The Pins weren't making good contact with the contacts inside the CAT5 port on the NIC card. Also check your NIC to ensure there is no damage the the metal contacts or check to see if it's clean and free of debris.
  8. taj1

    taj1 LI Guru Member

    @ Slim,

    Thanks for your advice, sorry for the late reaction.
    I swapped network cables without success. I changed the network card in the desktop computer. The other 2 computers can maintain file transfers of 6.8 MByte/s (=54 MBit/s, both are 100 MBit/s LAN cards) when both are on cable and over 2 MByte/s when one of both is wireless.
    Nevertheless, the old computer only plays mp3 right when connected to the (slower) wireless computer, and NOT when connected to an ~7 MByte/s capable wired computer. Playing mp3s does not need more than about 50 kByte/s. Therefore I really think that this is a combination of a slow computer and a WRT54G router problem.

    However, I'll come back to this: I'll change the Realtek8139 ethernet card for a 3com FE575 card. That will at least give the CPU of the old computer a bit more breathing space and may solve my problem. Still I think that there is a router problem.
  9. Neo_Giles24285

    Neo_Giles24285 LI Guru Member

    not being funny but have you actually thought that the pc probably has trouble routing the pci bus fast enough for a 10/100 connection rather than the slower WLAN, maybe try with a different pc in the saem situation and see if that plays them ok ;) pc specs also seem a little low for winamp i beleive
  10. taj1

    taj1 LI Guru Member

    No worries, of course I realised that the PC has low specs. My point is that that slow computer is not capable of playing mp3 files from the remote computer when the remote computer (1 y old centrino laptop) is connected via wire, while the same slow computer can play the same mp3 file when the remote computer (the same laptop) is wireless. For details see my previous post (01-05-2007). Fast computers do not have problems with mp3 files in any case, but they may have problems with media that require higher bitrates.

    And of course I do not use the latest winamp version, but version 2.95. That works with local mp3 files and with remote mp3 files as long as the remote computer is wireless.
  11. ifican

    ifican Network Guru Member

    Back to what neo_giles said, it really does appear that the old machine cannot keep up with buffering the data stream. When the other machine is wireles it has roughly half the throughput of when its wired. You only seem to have the issue when its wired. Im not sure if you can open 2 instances of winamp but open winamp and media player, play a song on both at the same time and see if you can produce the same dropouts that way.
  12. taj1

    taj1 LI Guru Member

    @ifican and Neo_Giles
    I tried to play both winamp and Media Player (version 6.4). That is not possible, only one programme can play music at a time. However, Media Player is capable of playing without interrupts (but more limited than Winamp, which van play playlists etc).
    I'll wait for the other network card and see how it goes.

    Ifican, you said: "When the other machine is wireles it has roughly half the throughput of when its wired." Why is that? Do you mean that wireless data transfer (including WPA encryption) is more efficient? And that the router creates more dataflow on the other end when a computer is wired. I find that hard to believe.

    I know that I repeat myself, but I just cannot understand why the network performance of one (slow) computer would be influenced by the way the other computer is connected, as long as the data flow is far below the limit (i.e. far less than 10% in any case) of other computer's or the router's capacity.
    In other words: why can the slow computer keep up buffering when the other computer is wireless and why not when the other computer is wired?
  13. Neo_Giles24285

    Neo_Giles24285 LI Guru Member

    what we mean is taj1 is that a wirless connection is 54mbps whereas a wired is 100mbps meaning with the wireless there only half as much of the data stream that the pc needs to receive and buffer, think of it as me and you standing opposite and throwing balls to eachother, say wired is 2 balls and wireless as 1, you'd find it easier to concentrate on catching and throwing back the 1 ball, ie wireless, than you would 2 balls. hope this helps
  14. taj1

    taj1 LI Guru Member

    Thanks for the info. I did not know that. Apparently, the fact that one end has a fast connection slows down the slow end even more. I would expect that the faster end would adapt its speed to the slower end (and throw fewer balls ;) ). And the slower end is much much slower even than the slowest wireless speed.
  15. taj1

    taj1 LI Guru Member

    As suggested, changing the network card solved the problem.
    Going from a Realtek8139 to a 3com Fe575 card increased network speed dramatically:
    Normal file transfer from a wired computer: changed from 300 kBytes/s to 1.8 MBytes/s
    Normal file transfer from a wireless computer: changed from 700 kBytes/s to 1.1 MBytes/s
    mp3 playing locally and downloading file from remote wired: from 25 kBytes/s to 700 kBytes/s(!)
    These numbers sound far more logical to me (wired connection is faster than wireless)
    No mp3 dropouts anymore.

    So, the take home message is: if you have on old computer to play mp3's from another computer: get yourself a decent network card.

    My problem is solved, but still I think that the problem that I observed was caused by something sub-optimal in the way the router handles wired network traffic.
  16. GavinLeigh

    GavinLeigh Guest

    Network Card

    There's an outside possibility it was a duplex mismatch on the network card. The router tries to send at 100mbps and the old network card could maybe only handle 10. I know that we still see throughput issues connecting older equipment to new networks. Often manually forcing the TCP settings to 10mbps on a switch port can get a piece of legacy equipment to talk happily again. Or in this case adding a newer card to the old PC.

    Just a passing thought. :)
  17. Neo_Giles24285

    Neo_Giles24285 LI Guru Member

    glad you got this sorted :cool1:
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