Cisco Cisco Packet Data Gateway (PDG)

 

 

 

2. 

After P-GW selection, SaMOG performs S2a procedures towards GGSN/PGW by including the PDN-Type, and receives 
the IPv6 Prefix for the subscriber's UE using S2a procedures as per APN subscription profile at P-GW 

3. 

SaMOG sends the Radius Access-Accept message towards WLC. 

4. 

The UE sends the IPv6 ICMPv6 Router Solicitation (ICMPv6 Type 133) message to the destination as "Link-Local Scope 
multicast All Routers Address (ff02:2)" with the source address as UEs Link-Local address. The UE also includes the 
ICMPv6 option "source link-layer address", which is the MAC address of the UE. 

5. 

For EoGRE access type sessions, the WLC is transparent between the UE and SaMOG for Neighbor Discovery and 
DHCPv6 messages. 
The WLC forwards the above messages to SaMOG by adding an EoGRE Tunnel Header received from the UE over CAP-
WAP tunnel. 
Vice versa, the WLC discards the EoGRE tunnel header received from SaMOG and forwards the same to the UE over the 
CAP-WAP tunnel. 
The WLC sends the ICMPv6 Router Solicitation Message towards SaMOG by adding the EoGRE tunnel header. 

6. 

SaMOG processes the received ICMPv6 Router Solicitation message over the EoGRE tunnel and responds with an 
ICMPv6 Router Advertisement (ICMPv6 Type 134) message over the EoGRE tunnel towards WLC. 
The WLC also includes the RDNSS, DNSSL options as per RFC 6106. 

7. 

The WLC forwards the IPv6 Router Advertisement (RA) over the CAP-WAP tunnel based on the mapping maintained 
between the UE's MAC address and the CAP-WAP tunnel information. 

8. 

SaMOG sends unsolicited IPv6 Router Advertisement (RA) over the EoGRE tunnel by including the IPv6 options 
mentioned in Step 6. 

9. 

The WLC forwards the Unsolicited IPv6 Router Advertisement (RA) over CAP-WAP Tunnel based on the mapping 
maintained between the UE's MAC Address and CAP-WAP tunnel information. 

10. 

The WLC receives the DHPCv6 Information-Request message over the CAP-WAP tunnel to fetch the configuration 
parameters based on the UE's behavior by including the Client-identifier and Option Request option with "DNS Recursive 
Name Server" and "Domain Search List". 

11. 

The WLC forwards the DHCPv6 Information-Request towards SaMOG by adding the EoGRE tunnel header. 

12. 

SaMOG responds with a DHCPv6 Reply message over the EoGRE tunnel by including the "DNS Recursive Name Server" 
and "Domain Search List". 

13. 

The WLC forwards the DHCPv6 Reply message over the CAP-WAP tunnel based on the mapping maintained between the 
UE's MAC address and the CAP-WAP tunnel information. 

13. 

SaMOG acts as an Accounting proxy between the WLC and Radius Accounting Server where all Accounting messages will 
have "Framed-IP-Address" and "Framed-IPv6-Address" based on the PDN-Type. 

 

The table below describes the steps in the message flow for dual-stack support using SLAAC over EoGRE.