I was about to go on Amazon to buy my own CenturyLink branded fiber modem (Arris C2100T) to replace the one I am renting from the ISP (Arris C3000T), but then I read here on SuperUser that I might not even need their modem at all. My whole objective here is to save money, so obviously it'd be ideal if I could simply not replace the modem, but rather just stop renting it from CenturyLink. After all, I have the ISP rented modem in bridge-mode, so (as I understand it) it's essentially doing nothing. Here is my current setup:

  • ISP fiber-to-ethernet handoff/converter (Calix 716GE-i R2 ONT)
  • CenturyLink fiber modem (Arris C3000T) in bridge mode
  • My Cisco ASA 5505 router (full support for 802.1q VLAN tagging)

I already know my PPPoE credentials and am using them on the WAN port of the Cisco ASA. However, I am not doing any VLAN tagging. Do I just need to setupu VLAN tagging (ID 201) on the WAN port of my Cisco ASA, as the aforementioned SU post suggests? Of course I can (and will) simply try this out, but I want to get ahead of any potential pitfalls before I go attempting changes on my WAN link.

Update 1: Tried setting VLAN 201 on the WAN link (Eth0/0) of my ASA: no joy, could not obtain an IP. PPPoE did seem to authenticate fine, however. I am missing something, but not sure what as of yet.

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    If you want to simplify your network, the Cisco isn't required, but I understand the reason you have it :-) – Ramhound Feb 24 at 20:45
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    What exactly is a "fiber modem"? It would make sense if the fiber-to-ethernet converter was built into it, but you list that as a separate item – so what sort of device is the Arris C3000T? What's "fiber" about it" and what's "modem" about it? – grawity Feb 24 at 21:02
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    @grawity, Verizon does the same thing. You usually have the ONT (fiber to Ethernet converter) in the basement or garage. Then have the VZ "Fiber router" which is essentially no different than a regular router minus the moca port which feeds set-top boxes. Most likely they have locked the account to the mac-address of the Arris wan interface. – Tim_Stewart Feb 25 at 17:41
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    Try duplicating the WAN Mac address of the Arris WAN interface to the Cisco ASA WAN interface. (MAC cloning) if that fails, you may have to call them and ask them to release the DHCP binding on their end. – Tim_Stewart Feb 25 at 17:44
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    Unless you have some sort of totalitarian agreement with CenturyLink... This is usually a straight forward kinda thing, most ISPs don't force you to use their equipment. If they implied that at all I would escalate the request to customer retention. – Tim_Stewart Feb 25 at 17:56

The answer is YES - this is possible! However, I could not figure out how to configure the ASA properly, so I just used my pfSense router instead, which I prefer because it's more full-featured and easier to use.

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