Cisco Cisco Packet Data Gateway (PDG)
SaMOG Gateway Overview
▀ SaMOG Services
▄ SaMOG Administration Guide, StarOS Release 16
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records. The Weight field specifies a relative weight for entries with the same priority. Larger weights are given a
proportionately higher probability of being selected. The SaMOG Gateway uses the value of (65535 minus NAPTR
preference) as the statistical weight for NAPTR resource records in the same way as the SRV weight is used for SRV
records, as defined in RFC 2782.
proportionately higher probability of being selected. The SaMOG Gateway uses the value of (65535 minus NAPTR
preference) as the statistical weight for NAPTR resource records in the same way as the SRV weight is used for SRV
records, as defined in RFC 2782.
When both topology-based and weight-based selection are enabled on the SaMOG Gateway, topology-based selection is
performed first, followed by weight-based selection. A candidate list of P-GWs is constructed based on these, and the
SaMOG Gateway selects a P-GW from this list for call establishment. If the selected P-GW does not respond, the
MRME service selects the alternate P-GW(s) from the candidate list.
performed first, followed by weight-based selection. A candidate list of P-GWs is constructed based on these, and the
SaMOG Gateway selects a P-GW from this list for call establishment. If the selected P-GW does not respond, the
MRME service selects the alternate P-GW(s) from the candidate list.
GGSN Selection—MRME
The SaMOG Gateway uses the Gn’ reference point between the SaMOG and GGSN. The SaMOG (acting like an
SGSN) initiates the creation of PDP context a GTP tunnel with the GGSN for each UE. The SGTP is compliant to
Release 7 for GTPv1 specification 29.060. The GGSN selection is based on the DNS query.
SGSN) initiates the creation of PDP context a GTP tunnel with the GGSN for each UE. The SGTP is compliant to
Release 7 for GTPv1 specification 29.060. The GGSN selection is based on the DNS query.
The GGSN node is selected as per the 3GPP standard for resolving the IP address using DNS query. The DNS query
contains the dns-apn string in the form of <apn-name>.mncXXX.mccYYY.gprs, and the apn-name is obtained from
AAA-Server during Access-Accept message. The MCC and MNC values are derived in the following priority:
contains the dns-apn string in the form of <apn-name>.mncXXX.mccYYY.gprs, and the apn-name is obtained from
AAA-Server during Access-Accept message. The MCC and MNC values are derived in the following priority:
From the NAI sent by UE in Access-Request message in the form of
IMSI@wlan.mncXXX.mccYYY.3gppnetwork.org.
Local configuration
When SaMOG interacts with pre-release 7 network elements (RADIUS based interfaces) it uses A/AAA queries. When
SaMOG interacts with post-release 7 network elements (Diameter based interfaces) it uses the NAPTR queries.
SaMOG interacts with post-release 7 network elements (Diameter based interfaces) it uses the NAPTR queries.
RADIUS Accounting Proxy—MRME
The SaMOG Gateway's MRME service proxies RADIUS accounting messages to a RADIUS accounting server and
selects the server based on an IMSI range. Upon receiving an Accounting Stop message, the MRME service clears the
subscriber session.
selects the server based on an IMSI range. Upon receiving an Accounting Stop message, the MRME service clears the
subscriber session.
RADIUS Authentication Server—MRME
The SaMOG Gateway's MRME service terminates RADIUS authentication requests. IEEE 802.1X authenticators will
function as RADIUS clients and generate Access Request messages to authenticate and authorize the WLAN UEs.
function as RADIUS clients and generate Access Request messages to authenticate and authorize the WLAN UEs.
RADIUS Disconnection—MRME
The SaMOG Gateway’s MRME service generates RADIUS disconnect messages that are sent to the WLCs for
network/aaa initiated detach and admin disconnections. Statistics for these RADIUS disconnect messages can be
retrieved via bulk statistics or the output of CLI show commands. For a network initiated detach, the SaMOG Gateway's
MRME service sends a RADIUS disconnect message to the WLC as per RFC 3576, which is the RADIUS client.
Disconnect Message transactions between the WLC and SaMOG are authenticated using a shared secret mechanism.
network/aaa initiated detach and admin disconnections. Statistics for these RADIUS disconnect messages can be
retrieved via bulk statistics or the output of CLI show commands. For a network initiated detach, the SaMOG Gateway's
MRME service sends a RADIUS disconnect message to the WLC as per RFC 3576, which is the RADIUS client.
Disconnect Message transactions between the WLC and SaMOG are authenticated using a shared secret mechanism.
Reauthorization Support—MRME
The SaMOG Gateway's MRME service uses an STa interface re-authorization procedure between the 3GPP AAA server
and the trusted non-3GPP access network to enable the 3GPP AAA server to modify previously-provided authorization
parameters, which may occur due to a modification of a subscriber profile in the HSS.
and the trusted non-3GPP access network to enable the 3GPP AAA server to modify previously-provided authorization
parameters, which may occur due to a modification of a subscriber profile in the HSS.