Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
technical:ppp-primer [2023/09/25 06:44] admin [The PPPoE Protocol] |
technical:ppp-primer [2023/10/10 16:00] (current) admin [The PPPoE Protocol] |
||
|---|---|---|---|
| Line 2: | Line 2: | ||
| ===== Introduction ===== | ===== Introduction ===== | ||
| With simple TCP/IP based networks there are two common ways to quickly establish a network connection. | With simple TCP/IP based networks there are two common ways to quickly establish a network connection. | ||
| - | * Providing a **DHCP server** for the devices connecting to the network. Your phone and laptop connecting to the LTE router at home is a classic example. | + | * Providing a **DHCP server** for the devices connecting to the network. Your phone and laptop connecting to the WiFi router at home is a classic example. |
| * Providing a **PPPoE server** for devices connecting to the network. If you are a client of a WISP, the Customer premises equipment (CPE) at your home / office will most likely be a PPPoE client in order to provide connectivity to the WIPS's network. | * Providing a **PPPoE server** for devices connecting to the network. If you are a client of a WISP, the Customer premises equipment (CPE) at your home / office will most likely be a PPPoE client in order to provide connectivity to the WIPS's network. | ||
| - | * If you are not working for a WISP or ISP the exposure to PPPoE might be limited and this page will serve as a background primer. | + | * If you are not working for a WISP or ISP, the exposure to PPPoE might be limited and this page will serve as a background primer. |
| ===== Why use PPPoE ===== | ===== Why use PPPoE ===== | ||
| - | * PPPoE comes in handy when you want to manage access to a network. | + | * PPPoE comes in handy when you want to **manage access to a network**. |
| * The most basic PPPoE servers require a username and password combination before establishing a connection from the client. | * The most basic PPPoE servers require a username and password combination before establishing a connection from the client. | ||
| * The client is thus configured with a username and password in order to identify itself to the PPPoE server. | * The client is thus configured with a username and password in order to identify itself to the PPPoE server. | ||
| - | * More advanced PPPoE servers include support for RADIUS which feature a central user store and options like bandwidth limiting or data usage quotas | + | * More advanced PPPoE servers include support for RADIUS which feature a central user store and options like bandwidth limiting or data limits |
| * This all makes PPPoE a favorite method used by ISPs and WISPs to manage client connections. | * This all makes PPPoE a favorite method used by ISPs and WISPs to manage client connections. | ||
| - | * The other alternative option to PPPoE is to use a Captive Portal on the break-out point of a network with a DHCP server in order to manage network access, bandwidth and usage quotas. | + | * Compare this now with the home network of a LTE router. If someone connects to it (making use of DHCP) there is not really a way for you to prevent them from establishing a connection or limiting their bandwidth. |
| - | | + | * On the home network you might as an alternative option to PPPoE use a Captive Portal on the break-out point of a network with a DHCP server in order to manage network access, bandwidth and usage quotas. (Like the typical Guest WiFi networks) |
| ===== The PPPoE Protocol ===== | ===== The PPPoE Protocol ===== | ||
| Line 20: | Line 21: | ||
| * The PPPoE protocol is a **layer 2 protocol**. | * The PPPoE protocol is a **layer 2 protocol**. | ||
| * This means that it does not contain an IP Address and communication is between MAC Addresses (on the Data Link Layer) | * This means that it does not contain an IP Address and communication is between MAC Addresses (on the Data Link Layer) | ||
| - | * This is in a way similar to a DHCP discovery packet for instance where the request is broadcasted on the broadcast domain (data link layer). That packet | + | * This is in a way similar to a DHCP discovery packet for instance where the request is broadcasted on the broadcast domain (data link layer). That packet |
| - | * For a PPPoE client to find out if there are any PPPoE servers around it starts with the **PPPoE Discovery** stage. (Broadcast) | + | * For a PPPoE client to find out if there are any PPPoE servers around |
| - | * PPPoE servers will then reply to the client informing | + | * PPPoE servers will then reply to the client informing |
| * The client will then proceed to communicate directly with the server (Unicast) on the MAC level / layer 2 in order to establish the **PPP Session**. | * The client will then proceed to communicate directly with the server (Unicast) on the MAC level / layer 2 in order to establish the **PPP Session**. | ||
| * Once the session is establish, the data transmitted between the PPPoE client and PPPoE server will be wrapped inside the PPPoE and PPP protocols. | * Once the session is establish, the data transmitted between the PPPoE client and PPPoE server will be wrapped inside the PPPoE and PPP protocols. | ||
| Line 48: | Line 49: | ||
| * Finally you can see how the payload is wrapped inside a packet with PPPoE and PPP on the outside to transport it between the PPPoE client and PPPoE Server. | * Finally you can see how the payload is wrapped inside a packet with PPPoE and PPP on the outside to transport it between the PPPoE client and PPPoE Server. | ||
| {{: | {{: | ||
| + | |||
| + | ===== Conclusion ===== | ||
| + | * As you can see the PPPoE protocol is plain and simple, similar to Ethernet (which is on a lower networking layer). | ||
| + | * This explain its popularity. As they say // Simplicity is the Ultimate Sophistication// | ||
| + | |||