Cisco ASR 5000 Series Administration Manual page 20

▀ Basic Features and Functionality
Figure 3.
Step 1
The packet is redirected to ECS based on the ACLs in the subscriber's template /APN and packets enter ECS through
the Protocol Analyzer Stack.
Step 2 Packets entering Protocol Analyzer Stack first go through a shallow inspection by passing through the following
analyzers in the listed order:
Step a
Step b
Step c
Important:
Therefore, defining routing ruledefs for these analyzers is not required.
Step 3
The fields and states found in the shallow inspection are compared to the fields and states defined in the routing ruledefs
in the subscriber's rulebase.
The ruledefs' priority determines the order in which the ruledefs are compared against packets.
Step 4
When the protocol fields and states found during the shallow inspection match those defined in a routing ruledef, the
packet is routed to the appropriate layer 7 or 7+ analyzer for deep-packet inspection.
Step 5 After the packet has been inspected and analyzed by the Protocol Analyzer Stack:
Step a
▄ Cisco ASR 5x00 Enhanced Charging Services Administration Guide
20
Routing Ruledefs and Packet Inspection
Bearer Analyzer
IP Analyzer
ICMP, TCP, or UDP Analyzer as appropriate
In the current release traffic routes to the ICMP, TCP, and UDP analyzers by default.
The packet resumes normal flow and through the rest of the ECS subsystem.
Enhanced Charging Service Overview