Cisco Cisco Packet Data Gateway (PDG)
S-GW Changes in Release 17
▀ S-GW Enhancements for 17.0
▄ Release Change Reference, StarOS Release 17
576
configure
context context_name
egtp-service egtp_service_name
gtpc node-feature{ pgw-restart-notification [network-triggered-service-
restoration ] } | { network-triggered-service-restoration [ pgw-restart-notification ] }
restoration ] } | { network-triggered-service-restoration [ pgw-restart-notification ] }
no gtpc node-feature { pgw-restart-notification [ network-triggered-service-
restoration ] } | { network-triggered-service-restoration [pgw-restart-notification ] }
restoration ] } | { network-triggered-service-restoration [pgw-restart-notification ] }
end
Notes:
pgw-restart-notification
enables the PGW Restart Notification node-feature for EGTP Service.
network-triggered-service-restoration
enables the NTSR node-feature for the EGTP Service.
CSCuh34589 - MME restoration support at S-GW
Feature Changes
MME Restoration Support at the S-GW
MME restoration is a 3GPP specification-based feature designed to gracefully handle the sessions at S-GW once S-GW
detects that the MME has failed or restarted. If the S-GW detects an MME failure based on a different restart counter in
the Recovery IE in any GTP Signaling message or Echo Request / Response, it will terminate sessions and not maintain
any PDN connections.
detects that the MME has failed or restarted. If the S-GW detects an MME failure based on a different restart counter in
the Recovery IE in any GTP Signaling message or Echo Request / Response, it will terminate sessions and not maintain
any PDN connections.
As a part of this feature, if a S-GW detects that a MME or S4-SGSN has restarted, instead of removing all the resources
associated with the peer node, the S-GW shall maintain the PDN connection table data and MM bearer contexts for
some specific S5/S8 bearer contexts eligible for network initiated service restoration, and initiate the deletion of the
resources associated with all the other S5/S8 bearers.
associated with the peer node, the S-GW shall maintain the PDN connection table data and MM bearer contexts for
some specific S5/S8 bearer contexts eligible for network initiated service restoration, and initiate the deletion of the
resources associated with all the other S5/S8 bearers.
The S5/S8 bearers eligible for network initiated service restoration are determined by the S-GW based on operator's
policy, for example, based on the QCI and/or ARP and/or APN.
policy, for example, based on the QCI and/or ARP and/or APN.
The benefit of this feature is that it provides support for the geo-redundant pool feature on the S4-SGSN/MME. In order
to restore session when the MME receives a DDN, the S-GW triggers restoration when the serving MME is unavailable,
by selecting another MME and sending DDN. This helps in faster service restoration/continuity in case of MME/S4-
SGSN failures.
to restore session when the MME receives a DDN, the S-GW triggers restoration when the serving MME is unavailable,
by selecting another MME and sending DDN. This helps in faster service restoration/continuity in case of MME/S4-
SGSN failures.
MME Restoration Standards Extension
The solution to recover from MME node failures proposed in the 3GPP standards rely on the deployment of MME pools
where each pool services a coverage area. Following an MME failure, the S-GW and MSC/VLR nodes may select the
same MME that used to service a UE, if it has restarted, or an alternate MME in the same pool to process Network-
initiated signaling that it received in accordance with the NTSR procedures defined in 3GPP TS 23.007 Release 11.
where each pool services a coverage area. Following an MME failure, the S-GW and MSC/VLR nodes may select the
same MME that used to service a UE, if it has restarted, or an alternate MME in the same pool to process Network-
initiated signaling that it received in accordance with the NTSR procedures defined in 3GPP TS 23.007 Release 11.
For a failed MME, the S-GW will select an alternate MME from the associated NTSR pool in the round robin fashion in
each sessmgr instance.
each sessmgr instance.