Cisco Cisco Packet Data Gateway (PDG)
P-GW Changes in Release 17
▀ P-GW Enhancements for 17.1
▄ Release Change Reference, StarOS Release 17
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not have resolved the P-CSCF address. In this case, the P-GW did not include the P-CSCF in the PCO Options and the
request was still successful. This caused issues to VoLTE devices and a rescue attempt occur red with some other
technology like eHRPD or LTE. In such cases, the P-GW would not re-attempt the P-CSCF resolution and rather
continue with the empty P-CSCF request.
request was still successful. This caused issues to VoLTE devices and a rescue attempt occur red with some other
technology like eHRPD or LTE. In such cases, the P-GW would not re-attempt the P-CSCF resolution and rather
continue with the empty P-CSCF request.
New Behavior: If the P-CSCF address information is not available at the time of handoff, then the P-GW will attempt
to rediscover the P-CSCF address and include it as part of the handoff message exchange
to rediscover the P-CSCF address and include it as part of the handoff message exchange
CSCum51840 - eHRPD support: PGW fails to resolve P-CSCF address
Feature Changes
P-GW Failed to Resolved P-CSCF Address
During certain external or internal DNS failures the P-GW may not have been able to resolve the P-CSCF address
during new call setup. In this scenario, the P-GW did not include the P-CSCF in the PCO Options and the request was
still successful.
during new call setup. In this scenario, the P-GW did not include the P-CSCF in the PCO Options and the request was
still successful.
During LTE2eHRPD Handoff if local P-CSCF addresses were not present, then the P-GW would not reattempt the P-
CSCF resolution and continue with the empty P-CSCF request.
CSCF resolution and continue with the empty P-CSCF request.
Previous Behavior: During LTE2eHRPD Handoff if local P-CSCF addresses were not present, then the P-GW would
not reattempt the P-CSCF resolution and continue with the empty P-CSCF request.
not reattempt the P-CSCF resolution and continue with the empty P-CSCF request.
New Behavior: During LTE2eHRPD handoff if local P-CSCF addresses were not present, then the PGW will attempt
to resolve the P-CSCF address and include it in PBA.
to resolve the P-CSCF address and include it in PBA.
CSCum51844 - eHRPD Additional support for PCSCF Discovery
Feature Changes
eHRPD Additional Support for P-CSCF Discovery
Previous Behavior: Previously, the order of resolution of P-CSCF address was:
1. DNS resolution: (FQDN fetched from S6b)
2. P-CSCF Addresses via APN configuration
3. P-CSCF Addresses that were received from the IMSA configured locally under imsa-service
2. P-CSCF Addresses via APN configuration
3. P-CSCF Addresses that were received from the IMSA configured locally under imsa-service
New Behavior: Modified P-CSCF discovery logic. The order of resolution of P-CSCF address is:
1. DNS resolution: (FQDN fetched from S6b or APN config)
2. PCSCF Addresses that are received from the IMSA (IMSA based P-CSCF end to end support for V4 and V6)
3. P-CSCF Addresses via APN configuration
2. PCSCF Addresses that are received from the IMSA (IMSA based P-CSCF end to end support for V4 and V6)
3. P-CSCF Addresses via APN configuration