1
A mobile device is automatically associated to the service set identifier (SSID) broadcast by the access
points to establish and maintain wireless connectivity.
2
The access point (AP) or Wireless LAN controller (WLC) starts the authentication process using Extensible
Authentication Protocol (EAP) by sending an EAP Request ID to the mobile device.
3
The mobile device sends a response for the EAP Request ID back to the AP or WLC.
4
Upon successful authentication, the mobile device sends a DHCPv4 Discover message to the iWAG.
5
The iWAG sends a RADIUS Access Request to the AAA server asking it to authenticate the subscriber.
6
The iWAG creates a MAC-based ISG session and pulls the subscriber profile from the AAA server. If the
profile has the AAA attribute value as "Cisco-AVPair=mn-service=dual", then the subscriber is authorized
for both IPv4 and IPv6 data transfer. Similarly, the AAA attribute value of
"Cisco-AVPair=mn-service=ipv4" or "Cisco-AVPair=mn-service=ipv6" represents the IPv4 or IPv6
protocol, using which the subscriber is authorized to send data.
7
The iWAG checks whether the ISG session for the MAC address is initiated or created.
8
The AAA server sends the RADIUS Access Accept message to the iWAG.
9
If the received profile has "cisco-mpc-protocol-interface" attribute with value as GTP, then iWAG initiates
GTP tunneling by sending a Create PDP Context Request to the GGSN.
10
The GGSN sends a RADIUS Access Request to the AAA server.
11
The AAA server replies with a RADIUS Access Accept message to the GGSN.
12
The GGSN sends a Create PDP Context Response.
13
The GTP-U tunnel is established between the iWAG and the GGSN.
14
The iWAG sends the IPv4 address through a DHCP Offer message to the mobile device. The iWAG
provisions the IPv4 stack.
15
The IPv4 traffic can flow through the GTP-U tunnel.
16
The mobile device sends an IPv6 FSOL that could be router solicit, neighbor solicit, or neighbor
advertisement, to the iWAG.
17
In response to the IPv6 (RS) FSOL sent, the iWAG sends a router advertisement (RA) packet using SLAAC
that includes the IPv6 prefix, to the mobile device. The mobile device appends the IPv6 prefix to it's 64-bit
(EUI or MAC address appended with FFFE) to form a unique 128 bit address.
18
Both the IPv4 and IPv6 traffic can flow through the GTP-U tunnel.
The DHCPv4 Discover initiator may come at any point later in the call flow, that is, even after tunnels
are created. Though, the subscriber has requested only for a single ipv6 address, the iWAG requests both
ipv4 and ipv6 addresses from GGSN and the tunnel is a dual-stack tunnel while the session is a single
stack session until the second initiator is received from the mobile device.
Note
Intelligent Wireless Access Gateway Configuration Guide
OL-30226-03
125
Call Flows for Dual-Stack PMIPv6 and GTP
Dual-Stack Mobile IPoE Session with DHCPv4 as FSOL for GTP Call Flow
