Speed drops dramatically when Homeplug connected to router

Discussion in 'Networking & NAS' started by mjcairney, Mar 8, 2013.

  1. mjcairney

    mjcairney
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    Hi guys and gals, I really hope someone can help here. I have been suffering from very low download speeds recently, and just got a new router from Sky, which I thought had solved my problems.

    However, when I then reconnected my homeplug, speeds immediately dropped again - typical example Upload Speed, homeplug disconnected, is 6.6Mbps but, when the homeplug is reconnected, speed drops to as low as 0.20Mbps which immediately goes back up to around the original figure when the homeplug is disconnected again. I have tried three different homeplugs connected to the router and all give exactly the same problem.

    I have also tried different Ethernet cables from the homeplug to the router, but still the problem manifests itself. This has happened with two Sky Wireless N routers and I am now at a total loss as to what to try next, so any ideas/advice would be most welcome.

    Cheers,

    Martin.
     
  2. mickevh

    mickevh
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    I think you've more or less answered your own question in that it seems your HomePlug link is prooving to be the bottleneck.

    But to be sure:

    How are you measuring the performance?

    Be sure to know your "Bits" for yout "Bytes." Data networking link rates are usually expressed "Bits" (little "b" as in mbps) per second whereas things like Windows file copying and FTP'ing tend to be expressed in "Bytes" (big "B" as in MB/s.)

    Many ISP's provide "asymetric" Internet services in that, upload rates are less than download rates. For example, 8mbps ADSL services offer 8mbps download by may be as little as 1mbps or even less for upload.
     
  3. mjcairney

    mjcairney
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    Hi, thanks for taking the time to reply, much appreciated. My speed tests were done using speedtest.btwholesale.com which is the site recommended by one of the Sky second line support team. The speed was reported, as I wrote it in my first post, in Mbps. Perhaps I should also have mentioned that my problem manifests itself even when all the equipment connected via the homeplugs is not in use, it's just the very fact that the homeplug at the router is actually connected to the router, if you see what I mean. As soon as I disconnect the Ethernet cable, speed goes back up to where it should be, reconnect it and speed drops again.

    Cheers,

    Martin.
     
  4. mickevh

    mickevh
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    The "presence" of your Homeplugs should not affect the performance of things not directing traffic through them. So if you had something cabled direct to your router, (which would be an ethernet link) then it will be the same speed whether the HomepLugs are on or not.

    Except....

    If whatever is "the other end" of your HomePlugs is generating/receiving so much traffic to/from the Internet, then it could affect competition for your Internet link.

    Your Internet link has a finite bandwidth and once it's full, it's full. Online speed testers are not very good for checking local network performance because they are effectively showing the capacity of the slowest link between the test site and the machine running the test and that is usually the ISP link itself.

    If you have, or can get hold of, a pair of Windows PC's there are tools such as NetIO and iPerf which can be used to test local network perfomance without the ISP link.
     
  5. mjcairney

    mjcairney
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    But, as I said before, this is happening when nothing else is actually switched on, just when the Ethernet cable is connected between the router and the homeplug. As a matter of interest, the homeplugs at the "other end" are connected to my AV receiver (for Internet radio), my Panasonic BluRay recorder and the Sky box for "On Demand" services, but none are actually active when I am seeing my problem.

    Cheers,

    Martin.
     
  6. mickevh

    mickevh
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    Nothing particularly scarey looking there - apart from the fact that hooking up your plugs to your router hits performance.

    It might be interesting to disconnect everything from the "remote" end of your HomePlug link and see how that affects things. (Physically disconnect the ethernet cables - turning things off & standby modes won't be conclusive - some things are still network "active" even though they are "off.")

    Thus you'd have ISP+++Router---HomePlug:::HomePlug (nothing else)

    Thence break/make the Router---Homeplug (ethernet) link and see what the results are.

    In "normal" operation, what have you got at the "remote" end Homeplug - is there an ethernet switch or is the remote homeplug one of the sort with muliple ethernet ports and/or a Wi-Fi AP built in..?

    The symptoms would suggest that "something" at the remote end of the HomePLug link is spewing traffic. This can occur if there is a "loop" in the topology. The info. I asked about in the previous paragraphs should help us narrow that down.

    A diagram of your infrastructure might be useful too. It doesn't have to be pretty, just so long as it shows what's connected to what and how (ethernet, wi-fi, etc.)
     
    Last edited: Mar 9, 2013
  7. mjcairney

    mjcairney
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    Hi again. The router and one (200Mbps) homeplug are upstairs and three separate identical single port, no wifi, homeplugs are each connected by Ethernet cables to the three items mentioned in my previous post. I can't imagine any great amount of traffic going through any of them when they're in standby mode but will try as you suggest and connect each individually to see if I can find a "culprit", although have visitors coming tonight so that will have to wait until tomorrow.

    I really appreciate your interest and help.

    Cheers,

    Martin.
     
    Last edited: Mar 9, 2013
  8. mjcairney

    mjcairney
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    Hi, I have run some tests today and got some really weird results with testing done using speedtest.btwholesale.com and all speeds reported as Mbps, as follows:

    No homeplug connected to router: D/L 6.62 U/L 0.68
    Homeplug to Router only: D/L 0.24 U/L 0.12
    Same as previous: D/L 6.54 U/L 0.25
    Same as previous: D/L 6.50 U/L 0.68
    No homeplug connected to router: D/L 6.61 U/L 0.68
    Same as previous: D/L 6.52 U/L 0.55
    Same as previous: D/L 6.52 U/L 0.67
    Connect Sky Box to homeplug downstairs: D/L 0.75 U/L 0.00
    Same as previous: D/L 0.64 U/L 0.31
    Same as previous: D/L 6.57 U/L 0.45
    Same as previous: D/L 6.61 U/L 0.67
    Same as previous: D/L 0.27 U/L 0.17
    Disconnect Sky Box ex homeplug, connect AV Rcvr: D/L 0.35 U/L 0.26
    Same as previous: D/L 0.76 U/L 0.56
    Go back to no homeplug connected to router: D/L 6.48 U/L 0.60
    Same as previous: D/L 6.56 U/L 0.68
    Reconnect homeplug to router with AV Rcvr connected downstairs: D/L 6.47 U/L 0.68
    Same as previous: D/L 6.52 U/L 0.68
    Disconnect AV Rcvr reconnect Sky Box: D/L 6.48 U/L 0.58
    Same as previous: D/L 0.05 U/L 0.68
    Same as previous: D/L 0.69 U/L 0.68
    Disconnect homeplug from router: D/L 6.52 U/L 0.63
    Same as previous: D/L 6.54 U/L 0.68

    Please note that both the Sky Box and AV Receiver were in standby mode during above tests. I hope you can make some sense of the above, because, to me at least, the figures are daft.

    Cheers,

    Martin.

    D/L = Download Speed U/L = Upload Speed.
     
    Last edited: Mar 11, 2013
  9. mjcairney

    mjcairney
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    Looks like I have solved my problem. Until now I have always just plugged in the homeplugs and let them do their own thing. However, as a last resort today, before giving up on them, I decided to pair them and, unbelievably, my problem just disappeared and I am now getting consistent download speeds around the 6.8Mbps mark which will, no doubt, sound slow to some, but that's the speed I expect at my location, so I am now a happy chappy.

    Cheers,

    Martin.
     

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