Multiplexing - ZyXEL Communications P-794H User Manual

Chapter 7 WAN Setup
Ethernet frames into bridged ATM cells. ENET ENCAP requires that you specify a
gateway IP address in the Gateway IP Address field in the wizard or WAN
screen. You can get this information from your ISP.
7.6.1.2 PPP over Ethernet
The P-794H supports PPPoE (Point-to-Point Protocol over Ethernet). PPPoE is an
IETF Draft standard (RFC 2516) specifying how a personal computer (PC) interacts
with a broadband modem (DSL, cable, wireless, etc.) connection. The PPPoE
option is for a dial-up connection using PPPoE.
For the service provider, PPPoE offers an access and authentication method that
works with existing access control systems (for example RADIUS).
One of the benefits of PPPoE is the ability to let you access one of multiple network
services, a function known as dynamic service selection. This enables the service
provider to easily create and offer new IP services for individuals.
Operationally, PPPoE saves significant effort for both you and the ISP or carrier, as
it requires no specific configuration of the broadband modem at the customer site.
By implementing PPPoE directly on the P-794H (rather than individual computers),
the computers on the LAN do not need PPPoE software installed, since the P-794H
does that part of the task. Furthermore, with NAT, all of the LANs' computers will
have access.
7.6.1.3 PPPoA
PPPoA stands for Point to Point Protocol over ATM Adaptation Layer 5 (AAL5). A
PPPoA connection functions like a dial-up Internet connection. The P-794H
encapsulates the PPP session based on RFC1483 and sends it through an ATM PVC
(Permanent Virtual Circuit) to the Internet Service Provider's (ISP) DSLAM (Digital
Subscriber Line (DSL) Access Multiplexer). Please refer to RFC 2364 for more
information on PPPoA. Refer to RFC 1661 for more information on PPP.
7.6.1.4 RFC 1483
RFC 1483 describes two methods for Multiprotocol Encapsulation over ATM
Adaptation Layer 5 (AAL5). The first method allows multiplexing of multiple
protocols over a single ATM virtual circuit (LLC-based multiplexing) and the second
method assumes that each protocol is carried over a separate ATM virtual circuit
(VC-based multiplexing). Please refer to RFC 1483 for more detailed information.

7.6.2 Multiplexing

There are two conventions to identify what protocols the virtual circuit (VC) is
carrying. Be sure to use the multiplexing method required by your ISP.
128
P-794H User's Guide