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Wireless Networks Thread, Cisco routers in Technical; Cisco 3800 series routers - does anyone have one of these plugged into a decent switch and finding it's chucking ...
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    synaesthesia's Avatar
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    Cisco routers

    Cisco 3800 series routers - does anyone have one of these plugged into a decent switch and finding it's chucking out absolutely shedloads of duplex errors/CRC faults?
    Already raised a call with ISP to look into it but would like to have an unbiased idea if that would be normal. If it was anything else I'd have ripped it out and replaced it already but only noticed it Friday. Changed the cable, there's no patching inbetween. Internet access is fine and quite speedy but naturally it's worrying. Only thing I can think of top of my head is dodgy mdi/x setting on the router which ISP would have to do.

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    Duplex mismatch, For sure!

    Whats it plugging into?

    Try on your switch setting the duplex and speed and then clearing the interface to see if that fix's it.
    Last edited by LukeC64; 16th January 2012 at 02:29 PM.

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    synaesthesia (16th January 2012)

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    In other schools I have told them to force the port on the core switch to 100 Full, reboot the router and that seems to have solved things. It usually happened not long after install (and it is a 2851 btw unless you have been given the wrong one by mistake ... ) and we had a number of schools with issues as a result. For it to happen now makes me wonder ...

    I'll keep an eye on the call but has your router been power cycled recently? Sudden surge? It does seem a tad strange.

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    synaesthesia (16th January 2012)

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    synaesthesia's Avatar
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    No power cycles on the router (we're not allowed!) . Have forced full duplex on it and it's now fine. Have asked EMBC to close the call but did ask why exactly they force mode on the router - that's always been a no-no, *especially* on provider managed hardware!
    I'd say it's odd that it was never a problem before but the old switches just didn't have the ability to log that sort of information. Internet is *damned* slight quicker now, though!

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    GrumbleDook's Avatar
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    We never had this problem with the old routers ... it just seems to be a handful of these when connecting into certain brands of switches. I've had Cisco kit be a pig like that before and it is usually easier to make the other kit shout louder about what it wants to do. I was pretty sure we had mentioned it in previous meetings ... but if I forget at the next one please remind me. I'll also add a note onto the ticket too.

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    DT2
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    I've seen some duplex issues on 3800 series.
    At my old place we had a client with about half a dozen of these all throwing the same issues - wouldn't negotiate duplex speed when set to auto for some reason. I managed to get him to flash the IOS with the latest version and that seemed to calm it down. I think he was running v12 IOS, exact info is sketchy as it was a while ago.

    DT

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    synaesthesia (16th January 2012)

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    Yeah ... it is just strange. It seems to be dependant on what they connect on to as well. I had this with 2900s as well (I know ... I shouldn't have been using patch leads to string them together ... it is a long story).

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    All appears sorted after forcing duplex. As a side bonus we appear to be getting 40Mbps download and 61MBps upload currently. Not complaining.

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    Quote Originally Posted by synaesthesia View Post
    All appears sorted after forcing duplex. As a side bonus we appear to be getting 40Mbps download and 61MBps upload currently. Not complaining.
    No problem mate, I know that one off by heart, our old Junior kept doing it between Cisco and HP always get the same errors on the ports so soon as I seen the post, I knew it was that :P

    Do me fav and click thanks :P



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