The EPC QoS attributes now supported Gn SGSN can be briefly described as below:

Evolved-ARP (E-ARP): Evolved allocation or retention priority specifies the relative importance of a Radio Access Bearers as compared to other Radio Access Bearers for allocation or retention of the Radio access bearer. The EPC uses Evolved ARP, which has priority level ranging from "1" up to "15". Additionally, evolved ARP comprises of pre-emption capability and pre-emption vulnerability. The preemption capability information defines whether a bearer with a lower priority level should be dropped to free up the required resources. The pre-emption vulnerability information indicates whether a bearer is applicable for such dropping by a preemption capable bearer with a higher priority value.

APN-AMBR (per APN Aggregate Maximum Bit Rate): The APN-AMBR limits the aggregate bit rate that can be provided across all Non- GBR PDP contexts of the same APN (for example, excess traffic may get discarded by a rate shaping function). Each of those Non-GBR PDP contexts can potentially utilize the entire APN AMBR (for example, when the other Non- GBR PDP contexts do not carry any traffic). The PGW enforces the APN AMBR in downlink. Enforcement of APN AMBR in uplink may be done in the UE and additionally in the PGW.

UE-AMBR: The UE AMBR limits the aggregate bit rate that can be provided across all Non-GBR PDP contexts of a UE (for example, excess traffic may get discarded by a rate shaping function). Each of the Non-GBR PDP contexts can potentially use the entire UE AMBR (for example, when the other Non-GBR PDP contexts do not carry any traffic). The GBR (real-time) PDP contexts are outside the scope of UE AMBR. The RAN enforces the UE AMBR in uplink and downlink.

With this feature enhancement the SGSN now supports the following functionalities:

The following new command has been introduced in the QoS Profile configuration mode to enable or disable the SGSN to send EPC QoS parameters to GGSN:

config 
  quality-of-service-profile profile_name 
     [remove] epc-qos-params-in-gtpv1 { eps-subscription | gprs-subscription } 
     exit 

Notes:

A new keyword is introduced in the class command under the QoS profile configuration mode to configure the E-ARP values.

config 
  [remove] class { background | conversational | interactive | streaming } evolved-arp { preemption-capability capability_value | preemption-vulnerability vulnerability_value | priority-level level_value  } 
  exit 

Notes:

The existing command prefer-as-cap is used to instruct the SGSN to use either the local or subscription or both-subscription-and-local (lower of either the locally configured QoS bit rate or the subscription received from HLR/HSS) QoS configuration value as the capping value for the QoS parameters.

config 
 quality-of-service-profile profile_name 
  prefer-as-cap [ both-subscription-and-local | subscription | local ] 
  exit 

The existing command [remove] override-arp-with-ggsn-arp under the Call Control Profile is used to enable or disable the ability of the SGSN to override an Allocation/Retention Priority (ARP) value with one received from a GGSN. If there is no authorized Evolved ARP received from the GGSN, by default the SGSN continues to use the legacy ARP included in the Quality of Service (QoS) Profile IE.

config 
 call-control-profile profile_name 
  [remove] override-arp-with-ggsn-arp 
  exit 

The configuration can be verified by executing the show command show quality-of-service-profile full all . The following parameter is displayed if gprs-subscription is selected in the epc-qos-params-in-gtpv1 command:

Sending of epc-qos-params to GGSN : Enabled with GPRS Subs

Listed below are the show outputs and new statistics added for EPC QoS support on SGSN: