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Motorola

PMIPv4 Call Flows:Bearer Setup with Dual Anchoring

Parviz Yegani Vojislav Vucetic Almon Tang

(408) 832-5729 (732) 706-0496 (847) 435-2715

pyegani@cisco.com vvucetic@cisco.com almon.tang@motorola.com

3GPP2, Calgary, Canada, July 23, 2007

X50-20070723-xxxCalgary, Canada

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Dual Addresses Concept

The concept of dual IP addresses already exists

(one IP address for local interface and another IP address for home network )Mobile IPv4 Collocated Care-of Address (CCoA)

Mobile IPv6

Disadvantage of CCoA mode is tunneling overhead on the airlink. This overhead can be eliminated using FA CoA mode.

Visited address anchor provides mobility without host mobility management operation

Mobility Management using PMIPv4 definesPMA – Mobility Proxy Agent

LMA – Local Mobility Anchor

See draft-leung-mip4-proxy-mode-03.txt for details.

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Dual Anchor Architecture

Client obtains two IP addresses

– LoA in visited network

• Anchored in the LMA

• Obtained via DHCP or PMIP

– HoA in home network

• Anchored in the HA

• Obtained via CMIP

Handset policy dictates which address is used by which apps

– For SIP-based applications:

– LoA for RTP,

– HoA for SIP signaling

FA HAHomeAddressPool

LocalAddress

Pool

Application Signaling Path and BearerPath for Relaxed Latency Applications

Mobility Control Signaling omitted for clarity

LowLatency

Bearer Path

Home Address (HoA): Assigned by HALocal/Visited Address (LoA): Assigned by LMA

PM

IP

Tu

nn

el

srv-AGW

anc-AGW

MAG/PMA

LMA

MIPv4 Tunnel

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Functional Split

anc-AGW performs the following functions (scenario 3a only): LMA function for PMIPv4 operation

FA function for CMIPv4 operation

srv-AGW performs the following functions: Access router for Simple IP service (i.e. no FA service)

PMA/MAG functions for PMIP operation

AT has two functions MT provides Simple IP attachment to the CAN

TE provides Mobile IP over any access network (HRPD, LTE)

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PMIPv4 Tunnel Establishment

aAGW/(LMA)

HAsAGW/(MAG)

AT H-AAAeBS hPCRFV-AAA vPCRF

1. Successful Access Authentication and eBS-sAGW tunnel establishment

2. HAAA assigns HA, VAAA may assign LoA

4. DHCP Discover w/ Rapid Commit (LoA?)

6. DIAMETER Authorization Req

7. DIAMETER Authorization Response

5. PMIP RRQ (NAI, HoA=0,GRE key)

8. Assign LoA from local pool or AAA, Set up forwarding for LoA via PMIP tunnel

9. PMIP RRP (NAI, HoA=LoA, GRE key)

10. Set up forwarding between RAN PMIP session and inter-AGW PMIP tunnel

12. AT obtains the local IP address (i.e. LoA)

3. Apps requests simple IPv4 service

11. DHCP Ack w/ Rapid Commit (LoA)

PolicyDB

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CMIPv4 Tunnel Establishment

aAGW(LMA/FA)

HAsAGW(MAG)

AT HAAAeBS hPCRFVAAA vPCRF

13. Agent Advertisement (CoA=aAGW, FA challenge disabled)

14. CMIP RRQ (NAI, HoA=0, CoA=aAGW, HA=0, MHAE, MAAE, SrcIP=0, DstIP=aAGW)

15. CMIP RRQ (NAI, HoA=0, CoA=aAGW, HA=HA, MHAE, MAAE, SrcIP=aAGW, DstIP=HA)

21. CMIP RRP (NAI, HoA=HoA, HA=HA, MHAE, SrcIP=HA, DstIP=aAGW)

20. HoA from local pool or AAA; Set up forwarding path for HoA via aAGW-HA tunnel

22. Set up forwarding between aAGW-sAGW tunnel and aAGW-HA tunnel

16. AAA Access-Req (username=NAI)

17. AAA Access-Accept (username=NAI, MN-HA SPI/Key, HoA)

23. CMIP RRP (NAI, HoA=HoA, HA=HA, MHAE, SrcIP=aAGW, DstIP=Bcast)

24. AT obtains HoA via CMIP

18. DIAMETER Authorization Req

19. DIAMETER Authorization Response

PolicyDB

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Call Flow – Steps 1 - 121. AT performs a successful access authentication. A tunnel is successfully established between eBS and sAGW.

2. During access authetication the HAAA assigns the HA address for the AT. VAAA may also assign the LoA in this step.

3. AT’s application requests for simple IPv4 address.

4. AT broadcasts a DHCPDISCOVER message with the Rapid Commit option to the eBS. The message is sent to the sAGW through the tunnel between the eBS and the sAGW. AT uses the DHCPv4 Rapid Commit option [RFC4039] in order to obtain an IPv4 address and configuration information using a 2-message exchange rather than the usual 4-message exchange.

5. sAGW/MAG assigns a unique GRE Key (used for traffic between MAG and LMA) for the AT and sends a Registration Request to the aAGW/LMA. The message contains NAI, CoA=sAGW, HA=aAGW, GRE Key, HoA=LoA. The MN-HA Authentication Extension contains the SPI and authenticator value derived from MN-HA Key. The message’s source IP address and destination IP address are sAGW and aAGW, respectively.

6. aAGW/LMA authenticates the Registration Request and stores values for assigned LoA and aAGW/LMA in the mobility binding entry. aAGW sends a DIAMETER Authorization Request to the vPCRF, which relays to the hPCRF. hPCRF contacts the policy data base for AT’s policy profile.

7. Policy data base sends the AT’s profile to the hPCRF. hPCRF sends DIAMETER Authorization Response with the AT’s subscription policy to the vPCRF, which may add its own policy before relaying to the aAGW/LMA.

8. A Local Address (LoA) is assigned from a pool (or AAA via PMIP message) and a GRE Key (used for traffic between aAGW/LAM to sAGW/MAG) is assigned for the AT. The mobility binding entry is created for the AT using its NAI.

9. aAGW/LMA returns a PMIP RRP to the sAGW/MAG containing the LoA and the GRE key.

10. A tunnel interface between sAGW and aAGW is configured with Foreign Agent service. A host route is injected into the routing table, which sets up forwarding of packets to the Local Address (LoA) via the GRE tunnel interface.

11. The sAGW sends a DHCPACK message with the Rapid Commit option to the AT through the eBS-sAGW tunnel.

12. AT learns the LoA via DHCP. This LoA is anchored in the aAGW/LMA.

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Call Flow – Steps 13 - 21

13. FA sends Agent Advertisement (upon arrival of Agent Solicitation) on tunnel interface. The message contains CoA=aAGW, Registration Lifetime, etc. Note that FA challenge procedure is disabled. The source IP address = aAGW and destination IP address = link local multicast, broadcast, or LoA. The tunnel header has IP header with source IP address = aAGW and destination IP address = sAGW and GRE Key. The forwarding operation on the sAGW removes the tunnel header and sends the Agent Advertisement on to the relevant layer 2 session. The mapping of L2 session and GRE Key was set up in step #10.

14. When an Agent Advertisement is received on the AT, the Mobile IP client sends a Registration Request to the LMA/FA. The message contains Home Address = 0, Care-of Address=aAGW/LMA, Home Agent=HAor 0 (dynamic HA assignment), MN-HA Authentication Extension, and MN-AAA Authentication Extension. The forwarding operation on sAGW takes the Registration Request from the L2 session and encapsulates it with the tunnel header.

15. aAGW performs Foreign Agent function and processes the Registration Request received on the tunnel interface. aAGW relays the message to the HA (which is identified in the HA field or downloaded from the HAAA server. The message’s source IP address and destination IP address are aAGW and HA, respectively.

16. HA performs Home Agent function and processes the Registration Request. The MN-AAA Authentication Extension requires HA to send a AAA Access-Request to the HAAA server to authenticate the AT.

17. After HAAA server authenticates the AT, it sends AAA Access-Accept to the AAA client, HA. The message contains the authorization attributes for HA service (e.g. MN-HA security association).

18. HA authenticates the Registration Request using the MN-HA security association. HA sends a DIAMETER Authorization Request to the hPCRF which contacts the Policy DB for AT’s policy profile.

Policy DB sends the AT’s profile to the hPCRF. The hPCRF sends DIAMETER Authorization Response with the AT’s subscription policy to the HA. Included in the message is the S-CSCF address assigned to the AT for SIP service.

20. HA assigns the Home Address from a local address pool or assigned by the HAAA server. The mobility binding entry is created for the AT with NAI in Registration Request. A tunnel interface (either IPinIP or GRE) between aAGW and HA is created. A host route is injected into the routing table, which sets up forwarding of packets to the Home Address (HoA) via the tunnel interface.

21. HA sends a Registration Reply to the FA. The message contains NAI, HA=HA, assigned HoA, assigned S-CSCF, etc. The MN-HA Authentication Extension protects the message. The message’s source IP address and destination IP address are HA and aAGW, respectively.

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Call Flows - Steps 22 to 24

22. aAGW creates a tunnel interface between itself and HA upon reception of a successful Registration Reply. The forwarding is set up to forward packets between the tunnel to sAGW and tunnel to HA.

23. aAGW relays the Registration Reply to the AT. The message’s source IP address and destination IP address are aAGW and broadcast, respectively. This message is encapsulated to the sAGW. The forwarding operation on the sAGW removes the tunnel header and sends the Registration Reply on to the relevant L2 session (I.e., over the GRE tunnel established between eBS and sAGW).

24. The Mobile IP client on the AT obtains the Home Address at the completion of the CMIPv4 registration procedure. The AT also obtains the address of the application manager assigned to it.