Mobile I Pv 6 deployment opportunities in next generation 3GPP networks

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30 Ιουν 2012 (πριν από 4 χρόνια και 11 μήνες)

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Mobile IPv6 deployment opportunities in next
generation 3GPP networks
I. Guardini
E. Demaria
M. La Monaca
2
Overview of SAE/LTE
•Terminology
SAE (System Architecture Evolution): core network/system aspects
LTE (Long Term Evolution): new radio access (E-UTRAN)
•Main system characteristics
support for packet services only
OFDM radio technology
peak throughput per user : 100 Mbps DL and 50 Mbps UL (with a 20
MHz channel width)
multi-access core network: GERAN, UTRAN, E-UTRAN and non-3GPP
•Specifications to be completed by 2008
3
Logical architecture: non roaming
S5
SGi
S4
S3
S1 (CP)
PCRF
S7
S6a
HSS
Rx+
S10
2G/3G
SGSN
S11
Serving
Gateway
S5
Operator IP services
(e.g. IMS, PSS, ..)
MME
E-UTRAN
PDN
Gateway
ePDG
Untrusted
non 3GPP
IP access
Trusted
non 3GPP
IP access
HSS
S2a
S2b
S1 (UP)
eNB
eNB
X2
eNB:evolved Node B
MME:Mobility Management Entity (similar to the
control part of the SGSN)
PDN GW:access gateway towards Packet Data
Networks (similar to the GGSN)
SGi:interface towards Internet/Intranet
(equivalent to Giinterface in GPRS)
UTRAN
GERAN
Legacy
Networks
4
Interworking with non 3GPP accesses (I)
•SAE supports both host-based and network-based mobility
management solutions
Dual-Stack MIPv6 (host-based)
Proxy MIPv6 and MIPv4 in Foreign Agent mode (network-based)
•PDN GW works as MIP/PMIP Home Agent
when connected to a 3GPP access the UE can be assumed to be at
home in MIP sense
mobility within 3GPP accesses (E-UTRAN, UTRAN and GERAN) is managed in a
network-based fashion using 3GPP-specific protocols
service continuity is guaranteed in case the UE moves from a 3GPP
access to a non 3GPP access (or vice versa)
the UE communicates using the same IP address independently of the access
network it is attached to
5
Interworking with non 3GPP accesses (II)
•SAE distinguishes between “trusted”and “untrusted”non
3GPP accesses
•It is up to the operator to decide if a non 3GPP access is
trusted or untrusted
the decision is not based just on the access network technology but
may depend also on business considerations
•Interworking with an untrusted access is performed via an
evolved PDG (ePDG)
the ePDGis similar to a VPN concentrator
the UE has to establish an IPsectunnel with the ePDGto access
operator’s services
the ePDGmay implement IP mobility protocols (e.g. PMIPv6)
6
Interworking with non 3GPP accesses (III)
•Interworking with a trusted access is performed using a
more lightweight procedure
the UE does not need to establish an IPsectunnel with the ePDGin
advance
MIP or PMIP protocols can be used directly between the non 3GPP
access network and the SAE core network
the non 3GPP access gateway (e.g. ASN GW in case of mobile WiMAX) can run
PMIPv6
7
Interworking with non 3GPP accesses (IV)
SGi
S7
HSS
Rx+
S4
S3
S1 (CP)
S10
2G/3G
SGSN
S11
MME
S1 (UP)
E-UTRAN
S6a
Serving
Gateway
Operator IP services
(e.g. IMS, PSS, ..)
S2a
S2b
UE
S2c
3GPP AAA
Server
Wa*
Ta*
Wm*
S6c
Wx*
PCRF
PDN
Gateway
ePDG
Untrusted non
3GPP IP access
(network-based)
Trusted non
3GPP IP access
(network-based)
HSS
HA
HA
Trusted/untrusted
non 3GPP
(host-based)
8
Protocols on non 3GPP interfaces
•The protocols that have been selected for mobility
between 3GPP and non 3GPP accesses are
S2a reference point (trusted non 3GPP accesses): Proxy Mobile IPv6
and Mobile IPv4 in Foreign Agent mode
Mobile IPv4 in FA mode was requested by CDMA2000 operators (e.g.Verizon),
that want to re-use their already deployed Mobile IPv4 infrastructure
S2b reference point (untrusted non 3GPP accesses): Proxy Mobile
IPv6 with dual-stack extensions
S2c reference point (host-based mobility on trusted/untrusted
accesses): Dual-Stack Mobile IPv6 (DSMIPv6)
the usage of Mobile IPv4 in co-located mode is still under consideration
9
Interworking scenarios: non roaming
Serving
GW
PDN
GW
3GPP
access
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
UE
S2a
S2b
SGi
S5
S1u, S4,
S11
Proxy Mobile IPv6
or MIPv4 in FA mode
Serving
GW
3GPP
access
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
UE
S2cS2c
SGi
S5
S1u, S4,
S11
PDN
GW
Dual-Stack
Mobile IPv6
Network-based
Mobility
Host-based
Mobility
10
Interworking scenarios: roaming (I)
Serving
GW
PDN
GW
3GPP
access
Serving
GW
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
3GPP
access
HPLMN
VPLMN
UE
S2a
S2b
S1u, S4,
S11
S8b
SGi
S5
S1u, S4,
S11
Proxy
Mobile IPv6
Serving
GW
PDN
GW
3GPP
access
Serving
GW
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
3GPP
access
HPLMN
VPLMN
UE
S2a
S2b
S1u, S4,
S11
S8a/b
SGi
S5
S1u, S4,
S11
GTP or Proxy
Mobile IPv6
PMIPv6 or
MIPv4 in FA mode
Network-based
Mobility
Proxy Mobile IPv6
11
Interworking scenarios: roaming (II)
Serving
GW
3GPP
access
Serving
GW
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
3GPP
access
HPLMN
VPLMN
UE
S2cS2c
S1u, S4,
S11
S8a/b
SGi
S5
S1u, S4,
S11
PDN
GW
Dual-Stack
Mobile IPv6
GTP or Proxy
Mobile IPv6
Host-based
Mobility
12
Interworking scenarios: roaming (III)
•This scenario has not been
officially accepted yet
the Serving GW works as a local
mobility anchor and runs PMIPv6
with the PDN GW
the home address is provided by the
PDN GW (i.e. the real HA)
data traffic is anchored on the PDN GW
the Serving GW handles local mobility
through DSMIPv6
the visited operator can use the Serving
GW to enforce policies (e.g. charging)
not clear how to handle Serving GW
relocation when the UE moves
across VPLMNs
Serving
GW
PDN
GW
3GPP
access
Trusted
non 3GPP
Untrusted
non 3GPP
ePDG
3GPP
access
HPLMN
VPLMN
UE
S1u, S4,
S11
S8b
SGi
S5
S1u, S4,
S11
Proxy
Mobile IPv6
Serving
GW
S2c
S2c
Host-based
Mobility
13
PMIPv6/MIPv6: summary of usage scenarios
PDN
GW
Serving
GW
Access
GW
PMIPv6PMIPv6
SGi
PDN
GW
Serving
GW
PMIPv6DSMIPv6
SGi
PDN
GW
Access
GW
PMIPv6
SGi
PDN
GW
DSMIPv6
SGi
Roaming and
non roaming
Roaming
(S2a/b)
(S2c)
(S8b)
(S8b)
(S2a/b)
(S2c)
Cascadeof PMIPv6 tunnels
Cascade of DSMIPv6 and PMIPv6 tunnels
Non 3GPP
Accesses
14
Roaming with or without local anchor
•Option A: no local anchor
HPLMN has to interface via
PMIPv6 with all non 3GPP AGWs
in VPLMN
complicates the establishment
and maintenance of roaming
agreements
•Option B: local anchor
PDN GW in HPLMN needs to
interface via PMIPv6 just with
the anchor point in VPLMN
simplifies the establishment of
roaming agreements
the visited operator can exploit
the local anchor to enforce
policies on UE’sdata traffic
PDN
GW
Non 3GPP
AGWs
BSs
HPLMN
VPLMN
PMIPv6 (S2a)
PDN
GW
Non 3GPP
AGWs
BSs
HPLMN
VPLMN
Serving
GW
PMIPv6 (S8b)
PMIPv6 (S2a)
No local anchor
A
Local anchor
B
15
Attachover S2a: trusted non 3GPP access (I)
16
Attach over S2a: trusted non 3GPP access (II)
•Step by step description of the procedure
1.The initial Non-3GPP access specific L2 procedures are performed
2.The EAP authentication procedure for network access is performed
involving the UE, trusted non-3GPP IP Access and the 3GPP AAA
Server. In the roaming case, there may be several AAA proxies
involved. The PDN GW information is returned as part of the reply
from the 3GPP AAA Server to the MAG in the trusted non-3GPP
access
3.After successful authentication and authorization, the L3 attach
procedure is triggered
4.MAG function of Trusted Non-3GPP IP Access sends Proxy Binding
Update message to PDN GW
5.The selected PDN GW informs the 3GPP AAA Server of its address
17
Attachover S2a: trusted non 3GPP access (III)
•Step by step description of the procedure (cont’ed)
6.The PDN GW processes the proxy binding update and creates a
binding cache entry for the UE. The PDN GW allocates IP address
for the UE. The PDN GW then sends a proxy binding
acknowledgement to the MAG function in Trusted Non-3GPP IP
Access, including the IP address(es) allocated for the UE
7.The PMIPv6 tunnel is set up between the Trusted Non-3GPP IP
Access and the PDN GW
8.L3 attach procedure is completed. IP connectivity between the UE
and the PDN GW is set for uplink and downlink directions
18
Attachover S2b: untrusted non 3GPP access
UE
ePDG
PDN GW
1
2
4
5
6
7
IKEv2 (IP Address Configuration)
IPsec Tunnel
HSS/
AAA
Proxy BU (MN-ID, IP addr Req)
Proxy Binding Ack
(IP addr)
PMIP Tunnel
IKEv2 authentication and tunnel setup
Authentication and Authorization
IPsec tunnel setup completion
3
Update PDN GW Address
19
Attachover S2b/S8b: cascadeof tunnels(I)
UE
ePDG
Serving
GW
1
2
3
5
6
7
HSS/
AAA
Proxy BU (MN-ID,
IP Addr Request)
Proxy Binding Ack
(IP Addr
Proxy BU (MN-ID,
IP Addr Req)
Proxy Binding Ack
IP Addr)
3GPP AAA
Proxy
IKE_AUTH Authentication
Authentication and Authorization
Authentication and Authorization
IPsec tunnel setup completion
IKEv2 (IP Address Configuration)
8
9
PDNGW
PMIP Tunnel
PMIP Tunnel
IPsec Tunnel
4
Update PDN GW
Address
20
Attach over S2b/S8b: cascade of tunnels (II)
•Step by step description of the procedure
1.The IKEv2 tunnel establishment procedure is started by the UE. The
ePDGIP address to which the UE needs to form IPsectunnel is
discovered via DNS query. The PDN GW information is returned as
part of the reply from the 3GPP AAA Proxy to the ePDG. This may
entail an additional name resolution step, issuing a request to a
DNS Server
2.The ePDGsends the PBU message to the Serving GW
3.The visited Serving GW processes the proxy binding update and
creates a binding cache entry for the UE. Then the visited Serving
GW sends the PBU message to the PDN GW using its own address as
the MAG address. Note that the binding cache entry on the Serving
GW does not yet have the UE’sIP address information. This
information will be added to the binding cache entry after step 4
21
Attachover S2b/S8b: cascadeof tunnels(III)
•Step by step description of the procedure (cont’ed)
4.The selected PDN GW informs the 3GPP AAA Server of its address
5.The PDN GW processes the proxy binding update and creates a
binding cache entry for the UE. The PDN GW allocates an IP
address for the UE. The PDN GW then sends a proxy binding ackto
the Serving GW, including the IP address allocated for the UE.
Once the Serving GW processes the proxy Binding Ack, it stores the
UE’sIP address information in the binding cache entry
6.After the Proxy BU/Proxy BAckis successful, there is a PMIPv6
tunnel setup between the Serving GW and the PDN GW
7.The ePDGcontinues with the IKE_AUTH exchange
22
Attach over S2b/S8b: cascade of tunnels (IV)
•Step by step description of the procedure (cont’ed)
8.The ePDGsends the final IKEv2 message with the IP address in
IKEv2 Configuration payloads. The IP address sent in the IKEv2
configuration payload is the same address that the ePDGreceived
in the Proxy Binding Ackmessage
9.IP connectivity from the UE to the PDN GW is now setup
any packet in the uplink direction is tunneled to the ePDGby the UE using the
IPSectunnel. The ePDGthen tunnels the packet to the visited Serving GW. The
visited Serving GW then tunnels the packet to the PDN GW. From the PDN GW
normal IP based routing takes place
In the downlink direction, the packet for UE (HoA) arrives at the PDN GW. The
PDN GW tunnels the packet based on the binding cache entry to the visited
Serving GW. The visited Serving GW tunnels the packet based on the binding
cache entry to the ePDG. The ePDGthen tunnels the packet to the UE via
proper IPsectunnel
23
PMIPv6: an example scenario (I)
Serving
Gateway
Operator IP services
(e.g. IMS, PSS, ..)
PDN
Gateway
ePDG
Untrusted non
3GPP IP access
S2a
S2b
UE
E-UTRAN
AGW
MAG
MAG
Trusted non
3GPP access
MAG
MAG
Data
packets
HA
HA
PBU
PBA
24
PMIPv6: an example scenario (II)
Serving
Gateway
Operator IP services
(e.g. IMS, PSS, ..)
PDN
Gateway
ePDG
Untrusted non
3GPP IP access
S2a
S2b
E-UTRAN
MAG
MAG
Trusted non
3GPP access
MAG
MAG
Data
packets
UE
HA
HA
AGW
PMIP tunnel
Data
packets
25
PMIPv6 in 3GPP vs. PMIPv6 in IETF
•The PMIPv6 usage scenarios foreseen for 3GPP SAE/LTE
present some differences with respect to those in the
scope of the IETF MIP6 WG
PMIPv6 is used for inter-system handovers (i.e. handovers between
3GPP and non 3GPP accesses)
PMIPv6 is used as a global mobility protocol
PMIPv6 may be used in roaming scenarios, which means that the HA
and the Proxy Mobility Agent may be located in different
administrative domains
in the roaming case there is the possibility to have a cascade of
PMIPv6 tunnels (AGW –Serving GW, Serving GW –PDN GW)
in this way there is a local anchor point in the visited domain,that can be used
by the visited operator to enforce policies on UE’straffic
the local anchor also simplifies the establishment of roaming agreements
26
Conclusions
•IETF protocols will be extensively used for 3GPP-non-3GPP
mobility in UMTS Rel8
PMIPv6, DSMIPv6 and MIPv4 in FA mode
•Some open issues still need to be resolved/clarified
mobility mode selection (PMIPv6, DSMIPv6 and MIPv4 in FA mode)
multihoming(i.e. multiple interface) management
simultaneous usage of multiple access technologies for load-sharing
or performance optimization
combined usage of PMIPv6 and DSMIPv6 in case the UE moves into
an access network that does not support any mobility feature (e.g.
domestic/public WiFiaccess)
handover optimizations for tight interworkingwith mobile WiMAX
and/or CDMA2000