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Ongoing high upstream and lag

Hello again. Just a question is high upstream at 5.1. 51and over causing these errors across all 4 channels also dated 1970? Any info be great 5months issue ongoing im staying ahead of these techs that talk nonsense to me when they visit. Screenshot_20200418_145642_com.android.chrome.jpg

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Re: Ongoing high upstream and lag

Hi were just waiting for your picture to be authorised. 

The forum has lots of techs on it (maybe even one whose been to you) im sure we can help. 


Here to help! I'm a technician helping out whilst working from home. Find out more


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Re: Ongoing high upstream and lag

5 tech visits. Few of u guys r on the case 1 even said anotjer repull with rg11. Getting crazy now im losing faith only saving gravce 4 virgin is u cant get thru or cancsl let alone a new provider. Dnt want it to come to that although im due compensation

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Re: Ongoing high upstream and lag

Your image has been rejected. 


Here to help! I'm a technician helping out whilst working from home. Find out more


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Re: Ongoing high upstream and lag


@Steven83L wrote:

Your image has been rejected. 


Because the CM MAC address had been left in the screenshot - it only showed a couple of no RNG RSP messages and one of those was from when the Hub was starting up - which is where the 1970 comes from, until the Hub establishes a connection, it doesn't know what the data and time are so defaults to 01/01/1970.

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Re: Ongoing high upstream and lag

Oh hea mac was on it sorry. But the t3s what are doing n why

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Re: Ongoing high upstream and lag

It's part of the way DOCSIS works, every 30 seconds or so the Hub sends what's called a Ranging Request message back to the CMTS in the local headend. This message is basically a 'I'm still here message' and the CMTS should send a response back within 200ms. The response is called (not surprisingly) a Ranging Response and contains information that the Hub may need to process, slightly change timing, power levels, frequencies etc. If the Hub sends out a request and doesn't get a response back then it flags the error and resets it's clock. The CMTS needs to know regularly that the Hub is still active otherwise it won't allocate a time period, called a MAP Grant, in which it can transmit upstream data.

If the Hub misses sixteen consecutive RNG-RSP windows then it assumes it has lost connectivity and resets itself to try and regain a connection. These T3 events generally signify a problem with the upstream, it's more likely that the Hub sends the message out but the CMTS never receives it and hence doesn't sent the response.

The thing to bear in mind is that the occasional (one or two a day) is fine, the CMTS might be just too busy, there may be excessive latency on the upstream and the message doesn't get there in time; upstream latency is always an issue with DOCSIS, purely because of the way it works - but that's a whole different ballgame! You'll see the T3 events and think something has gone horribly wrong, but what isn't logged and you don't see are all of the successful RNG-REQ/RSP transactions.

You just need to watch out for excessive numbers of these occurring with increasing regularity.

Incidentally the other common log entries you may see are Sync Timing and MDD timeouts, which normally are indicative of downstream issues but again nothing to worry about if they are infrequent.

By the way, the above is somewhat over simplified but hopefully answers your question.

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Re: Ongoing high upstream and lag

Yes it does clarfied very well. I do get that t3 time out daily  when my hub restart forced by all the tech visits it resets. Upstream at mo is very high and no tech can lower it fitting wall plug attenuators which performance is worse but lower stil high around 51 52s. Trying to arrange the 6th tech 

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