Comcast is upgrading again to DocSis-3.1
Email says my current modem,(DocSis-3),wont work when they make the change.
I would like to know if my router will still work with the new system?

What model is your router?

From the Wikipedia description,
https://en.wikipedia.org/wiki/Docsis
DOCSIS 3.1 will allow faster Internet connections, so you may want to make sure your router can support them. Otherwise, even if your router is compatible with the new modem, you won't get the increased speed if the router is a bottleneck.

Router is Linksys-E1000

The E1000 is an older wireless N router which only supports up to 300 Mbps data transfer.

I looked all over for a docsis-3.1 router and I cant find anything. Either they don't label them with docsis or there are none out yet.From what I can tell 300mbps is at the top of the list of what Comcast offers right now.

I suppose it depends on what kind of speeds they are going to be providing, but here are some at Amazon.

Docsis modems

Is Comcast supplying you with the modem or are you expected to supply your own?
If I understand correctly, you currently have a separate modem and router.

Assuming they are separate, it's the modem that has to be DOCSIS 3.1 compatible and not the router -- and Comcast will be supplying you with the modem.

DOCSIS means:
Data Over Cable Service Interface Specification

It has to do with the connection between the modem and your ISP. As regards compatibility, it doesn't affect the ethernet or wireless connection your computers have with your router, or the connection between your router and the modem.

The reason to upgrade the router is that with the old router, you're not getting the speeds you could be getting (assuming Comcast is actually giving you those faster speeds at your subscription level). Your ethernet speeds will be capped at 100 Mbps for ethernet with that E-1000 router -- so if that router is connected to the modem by ethernet cable, you'll get a maximum of 100 Mbps. The 300 Mbps wireless is an optimistic maximum speed, and in all likelihood you'll get a lot less.

From what I understand, this DOCSIS 3.1 is capable of Gbit speeds. Hopefully, they will provide you with the modem and info on what kind of speeds they will by supplying.

I supply my own equipment. After 1 year the cost of the modem would equal the rental fee and from then on it is free.

So are you looking for a router/modem/access point combination?

Maybe find out what model Comcast would be supplying and buy one of those.

Good idea.
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EDIT:Checked some things out. Comcast has a compatible list of modems but not of routers.
After a little investigating I found 2 interesting routers:
1) The Norton Core Router. It is the most beautiful router I have ever seen. Check it out!
The problem is not only do you have to buy the router but after 1 year you have to pay $10 a
month for protection.
2) The TP Link Archer C7-AC1750 Router. Not only is it reasonable but It gets fantastic reviews.
Check it out and let me know what you think.

Oh, wow on that Norton Core Router! But $279 plus another $120 a year is also "wow!"

I really like the TP Link Archer brand. It's definitely not quite the eye appeal of the Norton Core though! The maximum throughput is 1.75 Gb where the Norton Core is 2.5. Did you ever find out speed what Comcast will be pushing through?

Didn't see any specs. Just a page with many new compatible modems.

Draclvr: I went with the TP-Link-1750 router. Here is a weird experience I had installing it.
I went through the installation steps and it seemed straight forward until I got to the question "Do you want to clone your Mac address". I didnt know what that meant so I said no since that was already highlighted. After doing all the steps I got "Installation failed". I couldn't figure out the problem so I went on YouTube for hints.I saw one short video where the fellow said "You must say yes to the "Do you want to clone your Mac address?" question. I went back and did the installation steps again but saying yes to that question this time and got a "Installation success" at the end. Here is my beef. I didn't know what that meant and I doubt many people would. There was no manual and only a "quick start guide" included and no where on that guide did it say to say yes to that question. If I hadn't found that obscure video I would still be working on the problem.

I would have had no idea what it meant either and would have done the same thing you did. Can't say I've ever run into in during a router installation either.

I know what "clone a MAC address" means, but I wouldn't know whether a particular ISP required it or not.

By default every router has a different MAC address. Unless you configure the new router to have the same MAC as the old one (by cloning it), the ISP won't recognize the new router as "your" router and will reject the connection.

Before routers allowed cloning of MAC addresses, you'd have to phone your ISP to have them accept the MAC address of the new router.

AH,thanks for that info. I doubt if the average user would know that.

I'm thinking that may have been part of why I couldn't get a new router to work a couple of years ago. I even sent one back... when the second one wouldn't work, I called my ISP and they said, "Oh, no. We have to do something here when you install a new router." Of course after whatever they did, the second one worked. How is the average user supposed to know this!!