z/OS Communications Server Version 2 Release 3 IPv6 Network and Application Design Guide IBM SC27-3663-30 Note: Before using this information and the product it supports, be sure to read the general information under “Notices” on page 149. This edition applies to Version 2 Release 3 of z/OS® (5650-ZOS), and to subsequent releases and modifications until otherwise indicated in new editions. Last updated: 2019-06-21 © Copyright International Business Machines Corporation 2002, 2019. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Figures................................................................................................................ vii Tables.................................................................................................................. ix About this document.............................................................................................xi Who should read this document................................................................................................................. xi How this document is organized.................................................................................................................xi How to use this document.......................................................................................................................... xi How to contact IBM service..................................................................................................................xii Conventions and terminology that are used in this information............................................................... xii Prerequisite and related information........................................................................................................xiii Summary of changes for IPv6 Network and Application Design Guide...................xix Changes made in z/OS Communications Server Version 2 Release 3..................................................... xix Changes made in z/OS Version 2 Release 2............................................................................................. xix z/OS Version 2 Release 1 summary of changes....................................................................................... xix Chapter 1. Internet Protocol Version 6................................................................... 1 Neighbor discovery...................................................................................................................................... 3 Comparison of IPv6 and IPv4 characteristics.............................................................................................3 Chapter 2. IPv6 addressing....................................................................................7 Textual representation of IPv6 addresses.................................................................................................. 7 Textual representation of IPv6 prefixes...................................................................................................... 8 IPv6 address space......................................................................................................................................8 IPv6 addressing model................................................................................................................................ 9 Scope zones................................................................................................................................................. 9 Categories of IPv6 addresses....................................................................................................................10 Unicast IPv6 addresses........................................................................................................................10 Multicast IPv6 addresses.....................................................................................................................13 Anycast IPv6 addresses.......................................................................................................................15 Typical IPv6 addresses assigned to a node.............................................................................................. 15 IPv6 address states................................................................................................................................... 15 Chapter 3. IPv6 protocol...................................................................................... 17 Extension headers..................................................................................................................................... 17 Fragmentation in an IPv6 network............................................................................................................17 Fragmentation and UDP/RAW..............................................................................................................18 Path MTU discovery................................................................................................................................... 18 IPv6 routing................................................................................................................................................18 Router discovery...................................................................................................................................19 ICMPv6 redirects..................................................................................................................................19 Dynamic routing protocols................................................................................................................... 19 Considerations for route selection.......................................................................................................21 Considerations for multipath routes....................................................................................................21 The VARY TCPIP,,OBEYFILE command and routes............................................................................. 22 Policy-based routing..................................................................................................................................22 ICMPv6.......................................................................................................................................................22 Multicast Listener Discovery......................................................................................................................23 iii Neighbor discovery.................................................................................................................................... 24 Router advertisements.........................................................................................................................24 Redirect processing..............................................................................................................................28 Duplicate address detection................................................................................................................ 28 Address resolution............................................................................................................................... 29 Neighbor unreachability detection...................................................................................................... 30 Assigning IP addresses to interfaces........................................................................................................ 30 Stateless address autoconfiguration................................................................................................... 30 IP address takeover following an interface failure .............................................................................31 How to get addresses for VIPAs...........................................................................................................32 IPv6 temporary addresses with random interface IDs............................................................................ 32 Configuring a TCP/IP stack to generate IPv6 temporary addresses.................................................. 33 Enabling a client application to use IPv6 temporary or public addresses......................................... 34 Displaying the configured and generated temporary or public address information.........................34 Default address selection..........................................................................................................................35 Policy table for IPv6 default address selection...................................................................................35 Default destination address selection................................................................................................. 36 Default source address selection........................................................................................................ 37 Configuring the policy table for default address selection................................................................. 39 Displaying the policy table for default address selection................................................................... 40 Enabling IPv6 communication between IPv6 nodes or networks in an IPv4 environment.................... 41 Enabling end-to-end communication between IPv4 and IPv6 applications........................................... 41 IPv6 application on a dual-mode