Cisco Cisco Packet Data Gateway (PDG)
P-GW Changes in Release 17
▀ P-GW Enhancements for 17.0
▄ Release Change Reference, StarOS Release 17
394
Bit rate granularity provided by different interfaces was not aligned in 3GPP specifications. For example, the PCRF
provided bits per second on the Gx and the GTP utilized kilobits per second. Due to the conversion of bps to kbps, there
were scenarios where the rounding off could have resulted in the incorrect allocation of MBR/GBR values.
provided bits per second on the Gx and the GTP utilized kilobits per second. Due to the conversion of bps to kbps, there
were scenarios where the rounding off could have resulted in the incorrect allocation of MBR/GBR values.
With this feature, a bitrate value sent on GTP interface will be rounded up if the conversion from bps (received from
Gx) to kbps results in a fractional value. However, the enforcement of bitrate value (AMBR, MBR, GBR) values will
remain the same. Once the value (in kbps) that is sent towards the Access side, it needs to be rounded up.
Gx) to kbps results in a fractional value. However, the enforcement of bitrate value (AMBR, MBR, GBR) values will
remain the same. Once the value (in kbps) that is sent towards the Access side, it needs to be rounded up.
Previous Behavior: Previously, rounded-down kpbs bitrate (AMBR, MBR, BGR) values were being sent towards the
Access side.
Access side.
New Behavior: Bitrate granularity is still maintained per the current interface specifications but 3GPP provides
explicit guidance that whenever the conversion from bps to kbps results in decimal values, the node converting should
round the value up.
explicit guidance that whenever the conversion from bps to kbps results in decimal values, the node converting should
round the value up.
Introduced a new CLI command under P-GW service
[ no ] egtp bit-rates-rounded-down-kbps
to control the
behavior of rounding-up. The CLI command will enable/disable the old behavior of rounding down. By default, this
CLI command is configured to use rounded-up bitrate values. Depending on how the CLI is configured, either rounded-
up (Ceil) or rounded-down bitrate value will be sent on GTP interface towards the Access side. If the CLI command is
enabled, then it will result in the old behavior. This feature (rounding up the bitrate in kpbs) will be enabled by default.
Also,
CLI command is configured to use rounded-up bitrate values. Depending on how the CLI is configured, either rounded-
up (Ceil) or rounded-down bitrate value will be sent on GTP interface towards the Access side. If the CLI command is
enabled, then it will result in the old behavior. This feature (rounding up the bitrate in kpbs) will be enabled by default.
Also,
show subscribers pgw-only full all
will show the APN-AMBR in terms of bps. Previously,
show
subscribers pgw-only full all
used to show in terms of kpbs.
CR - C4-132189 - is defined for TS 29.274 for GTP conversion by P-GW.
Customer Impact: This feature provides for more consistent behavior and ensures correct bandwidth is allocated for
bearers.
bearers.
Command Changes
egtp bitrates-rounded-down-kbps
This new command enables/disables the previous behavior of rounding down.
configure
context context_name
pgw-service service name
[ no ] egtp bitrates-rounded-down-kbps
end
Notes:
The default behavior is to use rounded-up bitrate values.
Depending on how the CLI is configured, either rounded-up (Ceil) or rounded-down bitrate value is sent on the
GTP interface towards the Access side.
If the CLI command is enabled, then it will result in the previous behavior.
Performance Indicator Changes
show configuration context ingress