User`s guide

How Your Cayman 3220-H Works Cayman 3220-H User’s Guide
C-14 December 2000
 PPPoE requires no additional knowledge on the part of the end
user other than that needed for traditional dial-up Internet
access. Multiple users can share a broadband connection
without additional support or training costs, making it PPPoE
ideal for small offices/home offices.
 Cayman’s implementation of PPPoE is compatible with
networking products from Shasta/Nortel, Redback Networks,
and other standard industry servers.
PPP over Ethernet
Stages
A PPPoE connection has two stages: a Discovery stage and a PPP
Session stage.
Discover Stage
The Discovery stage of a PPPoE session consists of four steps:
1. Initiation – When a host wants to open a PPPoE session, it
sends out a PPPoE Active Discovery Initiation (PADI) broadcast
asking any available Access Concentrators to respond. If a host
does not receive a response within the timeout period, it
resends its PADI packet and doubles its timeout period.
2. Offer – If an Access Concentrator for the network can serve the
request, it sends a PPPoE Active Discovery Offer (PADO) packet
to the host identifying its name and the services it can offer to
the host. If more than one Access Concentrator is available, a
host may receive multiple PADO packets.
3. Request – The initiating host chooses an Access Concentrator
(based on its name or the services it offered in its PADO packet)
and sends a PPPoE Active Discovery Request (PADR) message
identifying the service it wants.
4. Confirmation – After the Access Concentrator receives the
PADR message, it generates a unique identifier for the PPPoE
session and replies to the host with a PPPoE Active Discovery
Session-confirmation (PADS) message. The PADS message
identifies the service under which the Access Concentrator has
accepted the PPPoE session.