ISP IPv6 Deployment Scenarios in Broadband Access Networks

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RFC 4779          ISP IPv6 Deployment Scenarios in BB       January 2007


   The host should have a wireless Network Interface Card (NIC) in order
   to connect to a WLAN network.  WLAN is a flat broadcast network and
   works in a similar fashion as Ethernet.  When a host initiates a
   connection, it is authenticated by the AAA server located at the SP
   network.  All the authentication parameters (username, password,
   etc.) are forwarded by the Access Point (AP) to the AAA server.  The
   AAA server authenticates the host; once successfully authenticated,
   the host can send data packets.  The AP is located near the host and
   acts as a bridge.  The AP forwards all the packets coming to/from
   host to the Edge Router.  The underlying connection between the AP
   and Edge Router could be based on any access layer technology such as
   HFC/Cable, FTTH, xDSL, etc.

   WLANs operate within limited areas known as WiFi Hot Spots.  While
   users are present in the area covered by the WLAN range, they can be
   connected to the Internet given they have a wireless NIC and required
   configuration settings in their devices (notebook PCs, PDAs, etc.).
   Once the user initiates the connection, the IP address is assigned by
   the SP using DHCPv4.  In most of the cases, SP assigns a limited
   number of public IP addresses to its customers.  When the user
   disconnects the connection and moves to a new WiFi hot spot, the
   above-mentioned process of authentication, address assignment, and
   accessing the Internet is repeated.

   There are IPv4 deployments where customers can use WLAN routers to
   connect over wireless to their service provider.  These deployment
   types do not fit in the typical Hot Spot concept, but rather they
   serve fixed customers.  For this reason, this section discusses the
   WLAN router options as well.  In this case, the ISP provides a public
   IP address and the WLAN Router assigns private addresses [RFC1918] to
   all WLAN users.  The WLAN Router provides NAT functionality while
   WLAN users access the Internet.

   While deploying IPv6 in the above-mentioned WLAN architecture, there
   are three possible scenarios as discussed below.

   A. Layer 2 NAP with Layer 3 termination at NSP Edge Router

   B. Layer 3 aware NAP with Layer 3 termination at Access Router

   C. PPP-Based Model

8.1.1.  Layer 2 NAP with Layer 3 termination at NSP Edge Router

   When a Layer 2 switch is present between AP and Edge Router, the AP
   and Layer 2 switch continues to work as a bridge, forwarding IPv4 and
   IPv6 packets from WLAN Host/Router to Edge Router and vice versa.




Asadullah, et al.            Informational                     [Page 56]