3. Encapsulating Security Protocol Processing

3. Encapsulating Security Protocol Processing

This section describes the processing of ESP packets in both outbound and inbound directions.

3.1. ESP Header Location

ESP may be employed in two ways: transport mode or tunnel mode.

3.1.1. Transport Mode Processing

Details of transport mode processing.

3.1.2. Tunnel Mode Processing

Details of tunnel mode processing.

3.2. Algorithms

The mandatory-to-implement algorithms for use with ESP.

3.2.1. Encryption Algorithms

Encryption algorithm specifications.

3.2.2. Integrity Algorithms

Integrity algorithm specifications.

3.2.3. Combined Mode Algorithms

Combined mode algorithm specifications.

3.3. Outbound Packet Processing

Processing of outbound ESP packets.

3.3.1. Security Association Lookup

SA lookup for outbound packets.

3.3.2. Packet Encryption and ICV Calculation

Encryption and ICV calculation procedures.

3.3.3. Sequence Number Generation

Sequence number generation rules.

3.3.4. Fragmentation

Fragmentation handling.

3.4. Inbound Packet Processing

Processing of inbound ESP packets.

3.4.1. Reassembly

Packet reassembly procedures.

3.4.2. Security Association Lookup

SA lookup for inbound packets.

3.4.3. Sequence Number Verification

Sequence number verification procedures.

3.4.4. Integrity Check Value Verification

ICV verification procedures.