Cisco Cisco Packet Data Interworking Function (PDIF)
SaMOG Gateway Overview
▀ SaMOG Services
▄ SaMOG Administration Guide, StarOS Release 17
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SaMOG Services
The SaMOG Gateway acts as the termination point of the WLAN access network. The SaMOG service enables the
WLAN UEs in the trusted non-3GPP IP access network to connect to the EPC network via Wireless LAN Controllers
(WLCs). During configuration, the SaMOG service gets associated with two services: the Convergence Gateway
(CGW) service and the Multi Radio Mobility Entity (MRME) service. These collocated services combine to enable the
SaMOG Gateway functionality.
WLAN UEs in the trusted non-3GPP IP access network to connect to the EPC network via Wireless LAN Controllers
(WLCs). During configuration, the SaMOG service gets associated with two services: the Convergence Gateway
(CGW) service and the Multi Radio Mobility Entity (MRME) service. These collocated services combine to enable the
SaMOG Gateway functionality.
CGW Service
The Convergence Gateway (CGW) service functions as a 3GPP Trusted WLAN Access Gateway (TWAG), terminating
the S2a interface to the GGSN/P-GW and acts as the default router for the WLAN UEs on its access link.
the S2a interface to the GGSN/P-GW and acts as the default router for the WLAN UEs on its access link.
The CGW service has the following key features and functions:
Functions as a Local Mobility Anchor (LMA) towards the WLCs, which functions as a Mobile Access Gateway
(MAG) with Proxy MIP capabilities per RFC 5213 and 3GPP TS 29.275 V11.5.
Enables the S2a interface towards the P-GW for session establishment per 3GPP TS 29.274 V11.5.0.
Enables the Gn interface towards the GGSN for session establishment per 3GPP TS 29.060 V11.5.0.
Routing of packets between the P-GW and the WLAN UEs via the Wireless LAN Controllers (WLCs).
Support for PDN type IPv4.
Interacts with the MRME service to provide user profile information to establish the GTP-variant S2a interface
towards the GGSN/P-GW per 3GPP TS 29.274.
Provides a Generic Routing Encapsulation (GRE) data path towards the WLCs per RFCs 1701 and 1702 for
tunneling of data towards the WLCs. Also follows RFC 5845 for exchanging GRE keys with WLC-based
PMIP signaling.
PMIP signaling.
Receives and sends GTPU data packets towards the GGSN/P-GW per 3GPP TS 29.281 V11.5.
CGW Features and Functions
The CGW service includes the following features and functions:
DSCP Marking—CGW
Differentiated Services Code Point (DSCP) levels can be assigned to specific traffic patterns in order to ensure that data
packets are delivered according to the precedence with which they are tagged. The DiffServ markings are applied to the
IP header for every subscriber data packet transmitted in the downlink direction to the WLAN access network. The four
traffic patterns have the following order of precedence:
packets are delivered according to the precedence with which they are tagged. The DiffServ markings are applied to the
IP header for every subscriber data packet transmitted in the downlink direction to the WLAN access network. The four
traffic patterns have the following order of precedence:
1. Background (lowest)
2. Interactive
3. Streaming
4. Conversational (highest)
2. Interactive
3. Streaming
4. Conversational (highest)
In addition, for class type Interactive, further categorization is done in combination with traffic handling priority and
allocation-retention priority. Data packets falling under the category of each of the traffic patterns are tagged with a
allocation-retention priority. Data packets falling under the category of each of the traffic patterns are tagged with a