LTE Reference Points
S1-MME
Reference point for
the control plane protocol between EUTRAN and MME. The protocol over this
reference point is eRANAP and it uses Stream Control Transmission Protocol
(SCTP) as the transport protocol
S1-U
Reference point
between EUTRAN and SGW for the per-bearer user plane tunneling and inter-eNB
path switching during handover. The transport protocol over this interface is
GPRS Tunneling Protocol-User plane (GTP-U)
Visit our Facebook Page
S2a
It provides the user
plane with related control and mobility support between trusted non-3GPP IP
access and the Gateway. S2a is based on Proxy Mobile IP. To enable access via
trusted non-3GPP IP accesses that do not support PMIP, S2a also supports Client
Mobile IPv4 FA mode
.
S2b
It provides
the user plane with related control and mobility support between evolved Packet
Data Gateway (ePDG) and the PDN GW. It is based on Proxy Mobile IP
S2c
It provides the user
plane with related control and mobility support between UE and the
PDN GW. This reference point is implemented over trusted and/or untrusted
non-3GPP Access and/or 3GPP access. This protocol is based on Client Mobile IP
co-located mode
S3
It is the interface
between SGSN and MME and it enables user and bearer information exchange for
inter 3GPP access network mobility in idle and/or active state. It is based on
Gn reference point as defined between SGSNs
S4
It provides
the user plane with related control and mobility support between SGSN and the
SGW and is based on Gn reference point as defined between SGSN and GGSN
S5
It provides
user plane tunneling and tunnel management between SGW and PDN GW. It is used
for SGW relocation due to UE mobility and if the SGW needs to connect to a
non-collocated PDN GW for the required PDN connectivity. Two variants of this
interface are being standardized depending on the protocol used, namely, GTP
and the IETF based Proxy Mobile IP solution .
Visit our Facebook Page
S6a
It enables
transfer of subscription and authentication data for authenticating/
authorizing user access to the evolved system (AAA interface) between MME and
HSS
S7
It provides transfer
of (QOS) policy and charging rules from Policy and Charging Rules Function
(PCRF) to Policy and Charging Enforcement Function (PCEF) in the PDN GW. This
interface is based on the Gx interface
S10
Reference point
between MMEs for MME relocation and MME to MME information transfer
S11
Reference point
between MME and SGW
Sgi
It is the reference
point between the PDN GW and the packet data network. Packet data network may
be an operator-external public or private packet data network or an
intra-operator packet data network, e.g. for provision of IMS services. This
reference point corresponds to Gi
for 2G/3G accesses
Rx+
The Rx reference
point resides between the Application Function and the PCRF in the 3GPP TS
23.203
Wn*
This is the reference
point between the Untrusted Non-3GPP IP Access and the ePDG. Traffic on this
interface for a UE initiated tunnel has to be forced towards ePDG.
Visit our Facebook Page