Zyxel C1100Z Slow Speed

joycebree

I have a VDSL2 web plan from CenturyLink in Colorado. Shockingly, they are the main ISP supplier for my location. 

I was first sent the Greenwave C4000LG from CenturyLink legitimately. This modem kept inconsistently disengaging and was unusable. There is by all accounts a great deal of firmware issues with it, from what I read on the web. 

I at that point requested another Zyxel C1100Z on eBay, which I am currently utilizing rather than the C4000LG. This modem is more steady however ordinarily gives me just 2 mbps of download speed. It at times differs for the duration of the day, going as high as 8 mbps. In any case, I pay for 30mbps and can get these velocities when associated by means of Ethernet. This modem ought to be equipped for 30 mbps on 2.4 GHz wifi utilizing the inherent switch, in light of the similarity list on CenturyLink's site. 

I took a stab at moving the Zyxel modem to somewhere else in my loft for a superior wired association area, yet none of the other DSL ports are giving a web association. I likewise took a stab at utilizing my own NetGear switch with the Zyxel C1100Z in straightforward crossing over mode, however that neglected to work despite the fact that I entered the right PPPoE accreditations.

Mijzelf

I think you are mixing up something. The C1100Z has 3 different functions, DSL modem, router and wireless access point. All these functions are more or less independent from each other, and have their own speed limits.

I pay for 30mbps

That is about the modem part. In the webinterface you should be able to find the speed at which the DSL modem has trained in. Maybe it mentions 2 speeds, Data Rate and Max. Attainable Data Rate. The second one is what the line could deliver, the first one what the modem actually has. If the Data Rate is 30Mbps or more, your ISP might deliver what you pay for. If the 2nd is lower than 30Mbps, the telephone line is not good enough to deliver 30Mbps.

that neglected to work despite the fact that I entered the right PPPoE accreditations.

As long as the modem doesn't have line sync, PPPoE cannot work. But if you have line sync, you should be able to see at which speed it trained in, in the webinterface, even without a working internet connection.

This modem ought to be equipped for 30 mbps on 2.4 GHz wifi

It's a 802.11b/g/n accesspoint, so yes, it is spec'd for 300Mbps max. In ideal circumstances. When you doubt if your ISP is delivering 30Mbps, you shouldn't use wifi to test, but a cable. There can be a lot of reasons why wifi has a limited bandwidth, including walls, floors, (coated) windows, microwaves, cheap Chinese wireless cameras, babyphones, and other accesspoints in the neighborhood.

factsmachine

@joycebree I have the C1100Z too, for nearly two years, and have much the same wi-fi experience on my computer as you do. "I have a VDSL2 web plan from CenturyLink in Colorado. This modem is ... (reliable but) ordinarily gives me just 2 mbps of download speed on wi-fi. It at times differs for the duration of the day, going as high as 8 mbps.   I pay for 30mbps and can get these velocities when associated by means of (hardwired) Ethernet cable."  

The wi-fi seems to have slowed down significantly in the past year, with no change (that I know of) to my configuration.  Sorry, I don't have any test benchmarks from 2019.  I called Centurylink tech support and we determined that I was getting 40mbps down when hardwired, but they weren't able to help with the wi-fi, even though I bought the router from them. 

The computer sometimes gets an 802.11n connection to the router, but other times only gets 802.11b.  Even 802.11b should give up to 11mbps.  The computer has received a maximum of 10mbps on the C1100Z wifi.  The firmware is up to date and I have tried a factory reset, and moving the router around, closer to and farther from the computer and in various orientations, but nothing seems to help.  

note: My computer can consistently get 40-60mbps when I use my neighbor's Spectrum wi-fi. I deduce that something is messed up with  the 1100Z wi-fi.  (A few people have suggested upgrading to either the C2100T (Technicolor), or the  C3000Z (Zyxel) router.  Oddly, the C2100Z is not listed as "recommended.")

factsmachine

@joycebree
My experience with the C110Z wifi is very much like yours. "I have a VDSL2 web plan from CenturyLink in Colorado.  This modem is ... (reliable) ... however ordinarily gives me just 2 mbps of download speed. It at times differs for the duration of the day, going as high as 8 mbps. In any case, I pay for 30mbps and can get these velocities when associated by means of (hardwired) Ethernet."

(This comment disappeared after the first time I posted it   I wonder who got pissed off, and why.)

The router seems to have slowed down in the past year. I don't have any benchmarks to prove it, except that I have two identical Android tablets which were adequate for web access, slow but tolerable; they have recently become intolerably slow.)  I tried moving and re-orienting the router and even doing a factory reset, but none of that helped.  My computer sometimes gets an 802.11d connection, and sometimes  802.11n connection, but the fastest download speed I have got from wifi is about 10mbps on this computer, but that is rare.

I called CenturyLink tech support, and we verified that the computer gets 40mbps download when hardwired to the router, but they couldn't really help with the wifi. I have been using the router for nearly two years, and it has up-to-date firmware.
 
note: My computer gets 40-60mbps reliably when I connect to my neighbor's Spectrum wifi. they have cable internet, but I don't know what kind of router they have. I'm going to try changing the wifi channels. 

update: trying different channels didn't help, but changing wireless setup>radio setup>802.11 mode from "b or g or n" to "g or n" got somewhat better (not great) speed.  I don't have any devices that need the old, slow mode b, but the computer was sometimes connecting that way.  Now it always connects in the faster mode n. 

factsmachine

After several days of working the problem, I have increased my wifi speeds from 2Mbps to 20Mbps.   Changing wireless setup>radio setup>802.11 mode from "b or g or n" to "g or n" got my speed up from 2Mbps to 10Mbps.  Finding a clear channel got my speed up from 10Mbps to 20Mbps.

The tool that was most useful for finding a clear channel was in the modem Utilities menu, in Wireless Diagnostics, called "AP Scan - 2,4 GHz" in the drop-down menu.  It populates a few tables, including the "Access Point Table" and the "Interfering Access Points" table.  The APT shows what channel is being used by nearby wi-fi networks.  The IAP shows which ones are interfering, and why.  By choosing a channel that was used by none of the other modems in the APT, all the "channel overlap" conditions in the IAP went away, leaving only the "close proximity AP" conditions.  This gave me the best performance., Hope that helps you.

Note: I had previously tried using the "Channel Diagnostic" tool, but found that it was slow and not reliable.