Npu Fastpath - Cisco ASR 5000 series Product Overview

Serving GPRS Support Node (SGSN) Overview
Condition
Mobile regains coverage
in different SGSN area
PDP deactivated during
LORC
PDP deactivated during
LORC
Refer to the SGSN APN Policy Configuration Mode chapter of the Command Line Interface Reference for the command
to configure the GTPC private extension and refer to the IuPS Service Configuratioin Mode chapter of the Command
Line Interface Reference to configure the LORC Cause IE.

NPU FastPath

NPU FastPath's proprietary internal direct tunnel optimizes resource usage and reduces latency when processing GTP-U
packets. This proprietary feature is only available on the ASR 5000 SGSN.
Incoming traffic passes through the switch fabric and the routing headers are changed to re-route traffic from the
incoming network processing unit (NPU) of the ingress PSC directly to the outgoing NPU of the egress PSC. This
means that intervening NPUs and CPUs are by-passed. This provides the SGSN with router-like latency and increased
node signaling capacity.
OL-22938-02
Triggered by
MS/SGSN
MS/SGSN
GGSN
SGSN Action
Send SGSN Context Response
message to new SGSN
Stop counting unsent
packets/bytes
Send DPCQ to GGSN
Stop counting unsent
packets/bytes
Send DPCR to GGSN
Stop counting unsent
packets/bytes
Cisco ASR 5000 Series Product Overview ▄
Features and Functionality - Basic ▀
LORC Intimation IE -
private extension payload
Unsent packet/byte counts
Unsent packet/byte counts
Unsent packet/byte counts