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donawalt's avatar
donawalt
Mentor
Dec 12, 2022
Solved

Procedure for replacing my modem?

Is there a procedure for replacing a cable modem that is used with a Orbi RBR850 system? I am replacing a CM1200 with a CM2000. I am assuming something like this:

 

1. Power off RBR850

2. Disconnect RBR850 cable(s) (I am using Link Aggregation) from cable modem)

3. Use Comcast app to plug in and activate new cable modem (per their instructions to use their app)

4. Connect RBR850 to the new modem and power up RBR850

5. Backup config file

 

Should I power down RBSs (I have 2) in step 1, or power cycle RBSs in step 4?

 

Thanks!

  • donawalt's avatar
    donawalt
    Dec 13, 2022

    The update/activation is complete, I have moved from a Netgear CM1200 modem to a CM2000 modem. Everything is resolved and working well, but there were some interesting moments in the process:

     

    • The biggest is after the activation and everything was back up, I noticed the RBR850 router had its DHCP address pool changed from 192.1.168.1->150 to 172.16.x.x! This caused havoc – some devices got a new DHCP, some did not. I ended up restoring my backup.cfg file and got the router back to the proper 192.168.1.x address pool and router address.
    • Speeds are fine – although my iPhone 14 Pro, which has WiFi 6, seems faster. Before it tested around 780/39 when about 6 feet from the router; after, it is 934/41. Directly connected Ethernet computers like my Mac are about the same, 925/40.
    • I have two things to upgrade for the full experience – I have a Cat6 cable from modem to RBR850, FURRYe38 recommends Cat6A. Second, my switch is a GS348 NETGEAR 48-Port Gigabit Ethernet Unmanaged Switch, which I am pretty sure does not support 2.5Gbps, which is why direct connect/Eth speeds are the same.
    • When the new modem was activated, I went from 4 ATDMA Bonded Upstream Channels to 5! Was that because the new modem could handle it or some other reason?
    • To have access/internet capability, I had to power cycle 3 of my 6 smart plugs, 1 Apple TV, 1 iPhone, and 1 of 3 HP printers – likely due to the issues cited in #1.

     

    Food for thought!

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  • FURRYe38's avatar
    FURRYe38
    Guru
    Dec 12, 2022
    donawalt wrote:

    Is there a procedure for replacing a cable modem that is used with a Orbi RBR850 system? I am replacing a CM1200 with a CM2000. I am assuming something like this:

     

    1. Power off RBR850

    2. Disconnect RBR850 cable(s) (I am using Link Aggregation) from cable modem) <Make sure you disable LAG on the RBR before disconnecting the RBR and powering it OFF. 

    3. Use Comcast app to plug in and activate new cable modem (per their instructions to use their app) <After the modem is associated with the ISP, either power OFF The modem or reboot the modem from it's web page. During the reboot or power off cycle, go to step 4 below. 

    4. Connect RBR850 to the new modem and power up RBR850

    5. Backup config file

     

    I highly recommend getting a CAT6A STP cable in between the CM2000 and RBR850 since you'll be at 2.5Gb connection rate between them.