A few days back, I realized WAN aggregation was the only way I could get total bandwidth to use my 1.2gbs xfinity service due to the 1gbs ports on my CM1200.I successfully enabled WAN aggregation and my download throughput jumped from 940mbs to 1.4gbs. I was over the moon thrilled in a house full of streamers.But then.. in Netgear style. After 24 hours my download test dropped to 800mbs. WTF right? I checked WAN configuration was active 1gbs + 1gbs, and I rebooted my modem. Magically it was 1.4gbs again. I tried a few hours and everything was good. Woke up this morning and back down to 800mps.Apparently.. this is common to the CM1200 with several different routers. But I can’t find a resolution. This is complete trash. I bought top of the line at the time and I’m ready to switch away from Netgear. Any help?

What router do you have? I don't have the CM1200 but I had a similar issue with an Arris SB8200 and the modem having issues. But I also had issues with specific routers improperly doing wan aggregation. It could be the modem. It could be the router. Tough to know 100% unless you have a PC that has dual lan ports to go modem--->PC directly for a period

Are the speeds good with out WAN Agg being enabled? Might post your CM modems cable connections and event log data please. jay_w wrote:A few days back, I realized WAN aggregation was the only way I could get total bandwidth to use my 1.2gbs xfinity service due to the 1gbs ports on my CM1200.I successfully enabled WAN aggregation and my download throughput jumped from 940mbs to 1.4gbs. I was over the moon thrilled in a house full of streamers.But then.. in Netgear style. After 24 hours my download test dropped to 800mbs. WTF right? I checked WAN configuration was active 1gbs + 1gbs, and I rebooted my modem. Magically it was 1.4gbs again. I tried a few hours and everything was good. Woke up this morning and back down to 800mps.Apparently.. this is common to the CM1200 with several different routers. But I can’t find a resolution. This is complete trash. I bought top of the line at the time and I’m ready to switch away from Netgear. Any help?

I have the RAX120… and I noticed in the router conversation a two year old (long long) thread that this was happening for many people using different routers. Technically you’re correct, either side can loose sync, and even though the 1+1 connection is green… the sync layers from either side could prevent both ports from being used… using only port but now with the overhead of a failed sync layer.

How are you testing speeds? Using the built in speedtest? If so, I wouldn't always trust that one as it doesn't always pick the best server to test from. It could be the rebooting choosing a different server. Just something to try next time it slows down

Thanks. I am using the Netgear app on the phone. Certainty not pinpoint accurate! Lol… so no measuring for small changes. These are big repeatable changes which are consistent.Before WAN aggregation… range was always 920-945mbs.After WAN aggregation.. range was 1410-1440.Like clockwork… after 22-24 hours… it just drops from the 1400mbs down to 800-840 …Repeatable and consistent. After rebooting modem, back to 1400 for 22-24 hours.I’ll keep looking otherwise, I’ll just have to disable, go back to my 940mbs … and wait for a good time to upgrade.

CM1200 WAN aggregation slows down (requires reboot)

15 Replies

plemans
Guru - Experienced User
Mar 13, 2024
What router do you have?
I don't have the CM1200 but I had a similar issue with an Arris SB8200 and the modem having issues. But I also had issues with specific routers improperly doing wan aggregation.

It could be the modem. It could be the router. Tough to know 100% unless you have a PC that has dual lan ports to go modem--->PC directly for a period
- jay_w
  Apprentice
  Mar 13, 2024
  I have the RAX120… and I noticed in the router conversation a two year old (long long) thread that this was happening for many people using different routers. Technically you’re correct, either side can loose sync, and even though the 1+1 connection is green… the sync layers from either side could prevent both ports from being used… using only port but now with the overhead of a failed sync layer.
  - plemans
    Guru - Experienced User
    Mar 13, 2024
    How are you testing speeds?
    
    Using the built in speedtest? If so, I wouldn't always trust that one as it doesn't always pick the best server to test from.
    
    It could be the rebooting choosing a different server.
    
    Just something to try next time it slows down
FURRYe38
Guru - Experienced User
Mar 13, 2024
Are the speeds good with out WAN Agg being enabled?

Might post your CM modems cable connections and event log data please.

jay_w wrote:
A few days back, I realized WAN aggregation was the only way I could get total bandwidth to use my 1.2gbs xfinity service due to the 1gbs ports on my CM1200.

I successfully enabled WAN aggregation and my download throughput jumped from 940mbs to 1.4gbs. I was over the moon thrilled in a house full of streamers.

But then.. in Netgear style. After 24 hours my download test dropped to 800mbs. WTF right? I checked WAN configuration was active 1gbs + 1gbs, and I rebooted my modem. Magically it was 1.4gbs again. I tried a few hours and everything was good. Woke up this morning and back down to 800mps.

Apparently.. this is common to the CM1200 with several different routers. But I can’t find a resolution. This is complete trash. I bought top of the line at the time and I’m ready to switch away from Netgear. Any help?

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CM1200 WAN aggregation slows down (requires reboot)