Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: Weaver on January 22, 2020, 04:23:33 AM
-
I have these good modems but they are not being manufactured any more and soon new ones will be hard to find and there will come a time when second hand ones in sake will be old and will maybe have had a lot of hours of usage, too many, and so are getting tired. So the question: in x years time where do I go? Need to look ahead for a current replacement with the same performance as a modem.
Does another ZyXEL modem that is current have the same performance?
-
The one I can see as a straight swap would be a Comtrend vr3030 but a bit pricey :( it uses a broadcom chipset
https://www.thekentongroup.com/wp-content/uploads/2016/01/VR-3030-Comtrend-User-Manual.pdf
-
@parkdale Same posh analog front end filter?
-
I believe the newer model is the VMG3926 (and a VMG3925 which also contains the infamous 63168 chipset).
Check the ending extensions carefully though.
See the links from here for summary and any discussions.
https://forum.kitz.co.uk/index.php/topic,14436.0.html
-
@kitz Does the VMG3926 / 3925 contain the good filter ?
-
From the link I posted above to the discussion threads in there there's a post by J0hn... and why I'd said check the ending extension (B10A etc) carefully
- The VMG3926-B10A contains the noise filter
- We are unsure about the B10B [update it doesnt]
See here for direct links to the relevant posts
https://forum.kitz.co.uk/index.php/topic,18246.msg324172.html#msg324172
https://forum.kitz.co.uk/index.php/topic,18246.msg383403.html#msg383403
-
You may also be interested in this
https://support.aa.net.uk/VMG1312_Vs_VMG3925
-
The one I can see as a straight swap would be a Comtrend vr3030 but a bit pricey :( it uses a broadcom chipset
https://www.thekentongroup.com/wp-content/uploads/2016/01/VR-3030-Comtrend-User-Manual.pdf
We tried a Comtrend here on our longish Huawei cab line about 6 months back. it worked in that it synced reliably, but we found it couldn't apparently handle a busy upstream link at the same time as downstream traffic. With a cloud backup job running, anything downstream ground to a halt. Swapped it out for a Vigor 130 and now a venerable VMG1312 & all those problems disappeared.
-
I found that a flat-out upload with my VMG 1312-10As while a long download was in progress could really hurt the downstream transfer rate; that is not good, but maybe things are just set up wrong so that the required number of ACKs are not getting through on time. I don’t really understand this though with TCP, because if one ACK cannot get through for ages then surely a later ACK will be sent upstream and it will have a later sequence number by then, so its effect will be to allow more stuff to be sent downstream by the remote end, and the later ACK will qualify as an ACK for all the non-received earlier ACKs.
-
Probably empty window at the sender side waiting for acknowledgements having sent your full receive window of data. If you're advertising a receive window of 500 kB the server will not have more than 500 kB of data 'in flight' to you without acknowledgement.