Cisco Cisco ASR 5000
Serving Gateway Overview
▀ Network Deployment(s)
▄ S-GW Administration Guide, StarOS Release 18
18
Figure 4.
S-GW in the E-UTRAN/EPC Network
Supported Logical Network Interfaces (Reference Points)
The S-GW provides the following logical network interfaces in support of the E-UTRAN/EPC network:
S1-U Interface
This reference point provides bearer channel tunneling between the eNodeB and the S-GW. It also supports eNodeB
path switching during handovers. The S-GW provides the local mobility anchor point for inter-eNodeB hand-overs. It
provides inter-eNodeB path switching during hand-overs when the X2 handover interface between base stations cannot
be used. The S1-U interface uses GPRS tunneling protocol for user plane (GTP-Uv1). GTP encapsulates all end user IP
packets and it relies on UDP/IP transport. The S1-U interface also supports IPSec IKEv2. This interface is defined in
3GPP TS 23.401.
Supported protocols:
path switching during handovers. The S-GW provides the local mobility anchor point for inter-eNodeB hand-overs. It
provides inter-eNodeB path switching during hand-overs when the X2 handover interface between base stations cannot
be used. The S1-U interface uses GPRS tunneling protocol for user plane (GTP-Uv1). GTP encapsulates all end user IP
packets and it relies on UDP/IP transport. The S1-U interface also supports IPSec IKEv2. This interface is defined in
3GPP TS 23.401.
Supported protocols:
Transport Layer: UDP, TCP