Understanding IPv6 Flow-Based Processing

This chapter explains how SRX Series Services Gateway and J-series devices handle flow-based processing for IP version 6 (IPv6) packets. To facilitate understanding of IPv6 flow processing for these devices, this chapter gives an overview of IPv6, including its address space and addressing. It also introduces the architecture for the SRX5600 and SRX5800 devices and uses it as a model to explain IPv6 flow processing. Flow processing is similar on other devices.

A flow is a stream of related packets that meet the same matching criteria and share the same characteristics. JUNOS Software treats packets belonging to the same flow in the same manner.

This chapter includes the following topics:

• Understanding IP Version 6 (IPv6)
• About the IPv6 Address Space, Addressing, and Address Types
• About IPv6 Address Types and How JUNOS Software for SRX Series Services Gateway and J-series Devices Use Them
• About the IPv6 Address Format
• The IPv6 Packet Header and SRX Series and J-series Devices Overview
• About the IPv6 Basic Packet Header
• Understanding IPv6 Packet Header Extensions
• About IPv6 Packet Header Verification Performed by the Flow Module for SRX Series and J-series Devices
• Understanding How SRX Series and J-series Devices Handle ICMPv6 Packets
• Understanding Path MTU Messages for IPv6 Packets
• Understanding How SRX Series and J-series Devices Handle Packet Fragmentation for IPv6 Flows
• Understanding Sessions for IPv6 Flows
• Understanding SRX5600 and SRX5800 Architecture and Flow Processing
• Enabling Flow-Based Processing for IPv6 Traffic
• Using Filters to Display IPv6 Session and Flow Information for SRX Series Services Gateways