Cisco Cisco Packet Data Interworking Function (PDIF) Documentation Roadmaps

Personal Stateful Firewall Overview

How Personal Stateful Firewall Works ▀

Cisco ASR 5000 Series Product Overview ▄

OL-22937-01

Figure 217. Stateful Firewall Processing

Data packet

received for ECS

processing

Is packet fragmented

yes

Buffer and wait for

fragments

IP header checks

Update statistics

and DoS attacks,

and drop the

packet

fail

pass

Matching flow exists

for the packet

Update flow stats

for packet

Transport layer

header and state

checks

fail

pass

Update statistics

and DoS attacks,

and drop the

packet

IP Reassembly

Update statistics

and drop the

packet

In progress

Transport layer

header and state

checks

Update statistics

and drop the

packet

fail

yes

fail

pass

done