1
|
UE initiates
an initial attach procedure towards WLC.
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2
|
WLC forms an
Access-Request message with EAP-Identity payload, User-Name and
Acct-Session-Id, and forwards the same to SaMOG.
|
3
|
SaMOG forms
an Access-Request towards the RADIUS AAA server, or a Diameter EAP Request
towards the STa AAA server using the attributes received from WLC.
|
4
|
AAA server
performs EAP authentication and forwards the Access-Challenge/Diameter EAP
Answer to SaMOG with the EAP payload.
|
5
|
SaMOG copies
the EAP payload to the Access-Challenge towards WLC.
|
6
|
WLC forwards
EAP Request with SIM Challenge towards UE.
|
7
|
UE sends EAP
response with SIM Challenge response.
|
8
|
WLC sends
Access-Request to SaMOG with EAP payload received from UE.
|
9
|
SaMOG sends
Access-Request/Diameter EAP Request to AAA server with the EAP payload.
|
10
|
AAA server
fetches the subscriber profile from HLR/HSS and validates the EAP Challenge
response sent from UE. Access-Accept/Diameter EAP Answer is sent to SaMOG with
user profile and EAP Success payload. SaMOG saves the user profile information.
The AAA server authorizes local offload for the subscriber and the APN provided
by AAA server has flow-based LBO enabled.
The AAA
server may also provide a rulebase name that is configured in SaMOG and has the
forwarding and NAT policy. The forwarding and NAT policy in turn has an ACL
configured to identify the packets to be forwarded to the EPC core.
|
11
|
SaMOG
performs DNS query with the DNS server and obtains the P-GW IP address.
|
12
|
SaMOG sets
up the GTP session with PGW by sending a Create Session Request message to PGW.
|
13
|
PGW responds
with a Create Session Response message and responds with the allocated UE IP
address (a.b.c.d).
|
14
|
SaMOG sends
Access-Accept to the WLC with EAP-Success payload.
|
15
|
WLC forwards
the EAP-Success to the UE.
|
16
|
DHCP or
PMIPv6 messaging is then initiated to setup the data path. The UE IP address
(a.b.c.d), DNS server address and default router address is supplied to the
WLC/UE in DHCP or PMIPv6 (PBA) message.
Once the WLC
learns the UE IP address, it sends an Accounting-Start message containing the
Framed-IP-Address attribute to SaMOG. SaMOG forwards it to the AAA accounting
server, and the response from accounting server is forwarded back to WLC.
|
17
|
The uplink
data packet with the source IP address (a.b.c.d) is sent to WLC through the
CAPWAP tunnel by UE
|
18
|
WLC
encapsulates the same packet into GRE/EoGRE tunnel and forwards it to SaMOG.
|
19
|
SaMOG
matches this packet with the ACL configured in the forward and NAT policy.
Here, the packet does not match the ACL. SaMOG performs dynamic NAT on this
packet. It allocates a global IP address from a pool (p.q.r.s) and replaces the
source IP address of the data packet with this address.
|
20
|
SaMOG routes
the modified packet to the Internet.
|
21
|
The
downlink packet contains the destination address set to p.q.r.s from the
Internet to SaMOG.
|
22
|
SaMOG
performs a reverse NAT and replaces the address (a.b.c.d) as the destination
address of the packet.
|
23
|
The
modified packet is forwarded to the WLC over GRE/EoGRE tunnel.
|
24
|
The WLC
forwards the packet to UE.
|
25
|
Another
uplink data packet with the source IP address (a.b.c.d) is sent to WLC through
the CAPWAP tunnel by UE.
|
26
|
WLC
encapsulates the same packet into GRE/EoGRE tunnel and sends it to SaMOG
|
27
|
SaMOG
matches this packet with the ACL configured in the forward and NAT policy.
Here, the packet does match the ACL.
|
28
|
SaMOG then
routes the packet to PGW over the GTP tunnel.
|
29
|
PGW
processes the packet and sends it to the Internet over the Gi interface, and
receives a downlink packet from the Internet.
|
30
|
The
downlink packet comes with the destination address set to a.b.c.d from PGW to
SaMOG over the GTP tunnel.
|
31
|
The packet
is forwarded to the WLC through the GRE/EoGRE tunnel.
|
32
|
WLC
forwards the packet to UE.
|