Cisco Cisco ASR 5000
APN Restriction
▀ How it Works
▄ SGSN Administration Guide, StarOS Release 18
Response as the latest value of the APN restriction associated with that APN. If there are any other PDN connections to
this APN, the SGSN updates the APN restriction associated with those PDN connections. If the APN restriction value is
not violated then the SGSN updates the APN restriction value for that PDN connection and any other PDN connection
to the same APN with the value received in the Create PDP Context / Create Session Response and re-calculates the
Maximum APN restriction value for MS.
this APN, the SGSN updates the APN restriction associated with those PDN connections. If the APN restriction value is
not violated then the SGSN updates the APN restriction value for that PDN connection and any other PDN connection
to the same APN with the value received in the Create PDP Context / Create Session Response and re-calculates the
Maximum APN restriction value for MS.
If APN restriction is enabled, but the SGSN does not receive any APN restriction value in the Create PDP Context /
Create Session Response and if another PDN connection exists to the same APN, the value of APN restriction is copied
from that APN. If no value is available, the APN restriction value is assumed to be "0".
Create Session Response and if another PDN connection exists to the same APN, the value of APN restriction is copied
from that APN. If no value is available, the APN restriction value is assumed to be "0".
If the current Maximum APN restriction value for the UE is present and the SGSN receives a new default bearer
activation request to another APN, while the APN restriction feature is enabled, the activation is rejected with the
appropriate sm cause.
activation request to another APN, while the APN restriction feature is enabled, the activation is rejected with the
appropriate sm cause.
If the Gn/ S4-SGSN receives a Create PDP Context/ Create Session Response as failure from the P-GW with EGTP
cause "EGTP_CAUSE_INCOMPATIBLE_APN_REST_TYPE (0x68)", then the Gn/ S4-SGSN sends an activate reject
to the MS with SM cause "(112) APN restriction value incompatible with active PDP context". Any de-activate request
sent to the MS due to APN Restriction violation also has the same SM cause.
cause "EGTP_CAUSE_INCOMPATIBLE_APN_REST_TYPE (0x68)", then the Gn/ S4-SGSN sends an activate reject
to the MS with SM cause "(112) APN restriction value incompatible with active PDP context". Any de-activate request
sent to the MS due to APN Restriction violation also has the same SM cause.
For every new activation request, the SGSN re-calculates the Maximum APN Restriction from among other currently
active PDN connections (excluding those PDNs for which any de-activation is ongoing.)
active PDN connections (excluding those PDNs for which any de-activation is ongoing.)
The APN restriction values are recovered during session recovery. In old SGSN ISRAU, the APN restriction associated
with each PDN is sent to the peer in Context Response. In old SGSN SRNS re-location, the APN restriction associated
with each PDN connection is sent to the peer in Forward Re-location Request.
with each PDN is sent to the peer in Context Response. In old SGSN SRNS re-location, the APN restriction associated
with each PDN connection is sent to the peer in Forward Re-location Request.
In IRAT procedures, the APN restriction for each PDN connection is transferred internally during IRAT and these
values are used for subsequent activations after IRAT.
values are used for subsequent activations after IRAT.
In new SGSN ISRAU, the APN restriction values received in context response are used in the subsequent activations
after ISRAU.
after ISRAU.
In new SGSN SRNS, the APN restriction values received in the forward re-location are used in subsequent activations
after SRNS re-location.
after SRNS re-location.
Limitations
Consider the scenario where APN restriction is enabled, but no value for APN restriction is received in the Create PDP
Context / Create Session Response and no other PDN connections exists to the same APN. An APN restriction value of
"0" is assigned to that PDN connection to denote that APN restriction value is invalid for that PDN. During subsequent
activations for the subscriber, if the SGSN receives a valid APN Restriction corresponding to the same APN, then the
APN Restriction value will be updated for the existing PDNs as well. If not, when a subsequent activation happens with
an APN for which SGSN receives valid APN Restriction value, the existing PDNs with invalid (that is "0") APN
Restriction values will be de-activated. This behaviour is also observed when the subscriber changes from one PLMN to
another PLMN, where the APN Restriction is enabled in the new PLMN but disabled in the old PLMN.
Context / Create Session Response and no other PDN connections exists to the same APN. An APN restriction value of
"0" is assigned to that PDN connection to denote that APN restriction value is invalid for that PDN. During subsequent
activations for the subscriber, if the SGSN receives a valid APN Restriction corresponding to the same APN, then the
APN Restriction value will be updated for the existing PDNs as well. If not, when a subsequent activation happens with
an APN for which SGSN receives valid APN Restriction value, the existing PDNs with invalid (that is "0") APN
Restriction values will be de-activated. This behaviour is also observed when the subscriber changes from one PLMN to
another PLMN, where the APN Restriction is enabled in the new PLMN but disabled in the old PLMN.
The SGSN does not support APN Restriction if it is enabled during an ongoing call. For APN Restriction to be applied
correctly for a subscriber, all the PDP contexts of the subscriber should be created after the APN Restriction is enabled.
correctly for a subscriber, all the PDP contexts of the subscriber should be created after the APN Restriction is enabled.
Standards Compliance
The APN Restriction feature complies with the following standards:
3GPP TS 23.060 (version 10)
3GPP TS 29.274 (version 10)