Visitor
•
2 Messages
SB8200 with 1 Gig plan
Just upgraded from 600mb to 1 gig speed home internet so I upgraded my modem from the SB6910 to SB8200 as its DOCSIS 3.1. Have spent the last 3 days with tech support to no avail. The sb8200 receive light is ONLY green (momentarily turned blue but only 3x in 3 days). Send light is solid green also, not blue even once. Old SB6910 had Blue lights for both and its DOCSIS 3.0. For the SB8200, Tech support had me contact Arris who said everything checks out except my lights should be blue with Xfinity for DOCSIS 3.1 and the cause is my Send power is low (all 5 channels were 40dBmV and should be 45) and on the receive side, power is good but 1 of my channels SNR is low also (27 and should be 33 min). So I went back to Xfinity and they of course insisted its hardware but I got them to reset and re-provision. I now have the following values and event log info if anyone can help. Really want this to work, thanks !
BruceW
Gold Problem Solver
•
26.3K Messages
3 years ago
Note that the SB8200 is not rated for use with Gigabit service. https://www.xfinity.com/support/devices says the device is approved for use with plan speeds up to 957 Mbps. Using devices on Internet speed tiers for which Comcast has not approved them tends to produce unexpected results, often speeds well below the manufacturer's ratings. It would be best to upgrade the device, or choose to a lower plan speed for which the device is approved.
Ever since Comcast changed the speed for Gigabit from 1000 to 1200 Mbps they require compatible devices to have an Ethernet port capable of line speeds of at least 2500 Mbps. The SB8200 does not appear to have one.
Arris began saying that upstream power should be "at least 45 dBmV" several years ago. I don't know why, because it's complete nonsense. The upstream power levels are controlled automatically and continuously by Comcast's equipment and do not need to be above 45 dBmV. That's because, as long as upstream power is not maxed out, what's important is not the level at the modem, it's the level (and quality) of the modem's signal as received at Comcast, which they control by adjusting the modem's transmit power. In fact, many customers have service that works perfectly fine with upstream modem power levels below 45 dBmV. Some even operate with the upstream below 35 dBmV.
Comcast's signal level ranges are given in https://forums.xfinity.com/conversations/your-home-network/connection-troubleshooting-tips/602da777c5375f08cdea3db9. If Arris' products did not work in those ranges, CableLabs and Comcast would never approve the devices.
Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post (by scrolling down to "Comment on this post here...") the author of the post you are Commenting on is notified of your response. But if you select Reply, the author of the post you are Replying to is NOT notified and may not be aware of your response.
(edited)
0
user_ffa639
Visitor
•
2 Messages
3 years ago
Thanks for the info, I was not aware. However, after tinkering around more this evening I am now getting 984mb down/24mb up consistently the last 2 hours. All modem lights remain Green too. IDK, but my fingers are crossed.
(edited)
1
0