I am familiar with PPPoE but getting confused with the term IPoE. Is this same as usual ethernet with DHCP server? Does this have any auth built-in? How do I get authenticated? What can a client connect? I did some googling but the information I got is still not clear.

Thanks, gs


So in the strictest sense, "IP over Ethernet" is exactly what it sounds like, it's the encapsulation of IP packets (datagrams, formally) in standard ethernet frames. For much of the networking universe this is just "normal" IP as so much of the transport has migrated to Ethernet nowadays. Somewhat more specifically speaking, IPoE is often used in comparison to PPPoE when discussing how services such as residential broadband are delivered to the end user. This can be a little confusing as PPPoE would more accurately be described as "IP packets encapsulated in PPP, which is in turn encapsulated in Ethernet"... but it's just broadly known as "PPPoE".

The use of either "PPPoE" or "IPoE" in the context of residential broadband also almost always implies other components of the service delivery system, such as address allocation, authentication, accounting, etc. Authentication is normally a RADIUS server or sometimes Diameter. The exact rules on how authentication is performed and what devices can/can't connect are usually set up by the specific service provider. Broadly speaking, "IPoE" is more common in cable access networks, and "PPPoE" is more common in DSL and dialup access networks: although this is by no means cast in stone.

I found the document below to be relatively useful:



IPoE is essentially DHCP-triggered subscriber interfaces.

It has come about because most modern broadband access networks are able to deliver Ethernet from end-to-end (e.g.: xPON/FTTH).

Users are "authenticated" through the use of DHCPv4/v6 Option-82 inserting their Circuit-ID into their initial DHCP Discovery - this identifies the physical location of the user based on the tail that they are connected to (this would be done at an aggregation switch between the xPON network and whatever backhaul gets them to their ISP of choice).

After this it's pretty much boring old Q-in-Q to deliver all users from a specific neighbourhood to their various ISPs.

The ISP will then service the DHCP request (if the Circuit-ID can be mapped to a valid user via RADIUS), provide an IP (and hopefully prefix-delegation if they're offering IPv6) and then create a logical interface representing that subscriber that you they apply their filtering/rate-shaping to and start grabbing stats from.

  • Thanks. Do you mean "Authentication" transparently and will happen between the DHCP server and "authentication server"? Is there a concept of user-name/password here? Will it work with DHCPv4? – user2148707 Mar 9 '17 at 12:47
  • Authentication will be basically - "should I give an IP address (and logical interface) to the user on port 48 of aggregation switch 7 in Smalltown" - no username and password required. And yes, DHCPv4 supports option-82 (I've edited my little mark above to indicate both v4 and v6) – Benjamin Dale Mar 9 '17 at 14:23

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