IPv6 summary

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IPv6

IPv6

Introduction

same function with IPv4 but stucture is different.

  • why IPv6

    • IPv4 address exhaustion

      IPv4耗尽

    • IPv6 Much larger address space

      更大的地址空间

    • Multicast

      多播

    • Jumbograms

    • Faster routing.

      更快的路径

    • Network Layer Security

      更安全的网络层

    • Mobility.

      流动性，移动

  • IPv6 security

    • Security features are standardised and mandated, i.e. all implementation must offer them.

      安全功能是标准化的，也是强制性的，即所有的设施必须提供这些功能。

    • Extension of RFC-2401 Security Architecture for the Internet Protocol (IPSec)

      RFC-2401互联网协议安全架构（IPSec）的扩展

    • Authentication and Encryption.

      认证和加密。

    • Invisible to applications as it operates within the IP layer.

      由于它在IP层内运行，对应用程序来说是不可见的。

    • It protects all upper layer protocols.

      它保护所有上层协议。

    • It protects both end-to-end and router-to-router communication (secure gateway).

      它既能保护端到端的通信，又能保护路由器到路由器的通信（安全网关）。

  • IPv6 address scope

    IPv6地址范围

    • Unicast addressing

      • Link-local Addresses (LLA)
      • loopback address

      Link-local Addresses (LLA) and the loopback address have link-local scope, which means they are to be used in the directly attached network (link) only.

      链接本地地址（LLA）和回环地址具有链接本地范围，这意味着它们只能在直接连接的网络（链接）中使用。

    • other addresses

      • Global Unicast Addresses (GUA)

      including Global Unicast Addresses (GUA), have global (or universal) scope, which means they are globally routable.

      包括全局单播地址（GUA），具有全局（或通用）范围，这意味着它们是全球可路由的。

  • mobile IPv6

    • IPv6 was designed to support mobility.

      IPv6是被设计成支持移动的

    • IPv6 ND and SLAAC allow hosts to operate in any locations without any special support.

      IPv6 ND(neighbor) 和 SLAAC(Stateless Address Auto-configuration) 允许主机在任何地方运行，不需要任何特殊支持。

    • It is more scalable and the performance is better because less traffic passes through the home link and less redirection and less rerouting.

      它的可扩展性更强，性能也更好，因为通过主链路的流量更少，重定向和重路由更少。

    • No single point of failure.

      没有单点故障。

  • IANA(Internet Assigned Numbers Authority) responsible for the entire IPv6 address space and they assign certain prefixes to the RIRs (Regional Internet Registry).

    IANA(互联网号码分配局)机构负责整个IPv6地址空间并且他们分配了前缀给RIRs（区域互联网注册机构）

    • RIRs
      • ARIN 北美
      • LACNIC 南美
      • RIPE 欧洲和亚洲北部
      • APNIC 亚洲
      • AFRINIC 非洲

  • RIPE issued the block 2001:4000::/23 by IANA

    IANA: 2000::/3

    RIPE 通过 IANA发布了区块 2001:4000::/23 欧洲和亚洲北部

    • ISP(Internet service provider) 2001:41f0::/32

      ISP互联网服务供应商

      • Customer :2001:41f0:4060::/48

    ARIN北美 2001:0400::/23

  • only global routing-prefix or site-prefix is /48, otherwise interface ID all would be /64

    只要全局路由前缀和站点前缀是/48，其他的接口ID都是/64

  • We can use 16bits to create subnet

    剩下16位可以创建子网

    image-20221207170502205

Ip address planning

1. IPv4 and IPv6 overall

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image-20221207175800161

  • 如上图所示，IPv6需要一次性完成4bits的分配，而且直接使用该范围内分配，不需要利用出事分配规模来计算

如下图所示

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2. Questions

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Structure

1. Address

  • Address format

    image-20221207183734639

    • Contiguous groups of ‘0‘ can be replaced with ‘::’

    • Only one double colon used in an address.

    image-20221207183820075

    • prefix

    前缀

    • Interface
    • Character must be represented in lowercase.

    必须用小写a-f.

  • Anycast type

    • Unicast
    • multicast
    • anycast

    IPv4 Broadcast concept disappears –Replaced by All hosts multicast.

    IPv4广播概念消失 -被所有主机多播取代。

  • IPv6 Network Notation

    网络标记

    • image-20221207185133437

  • Special address

    • Unspecial address

      ::

    • Default route address

      image-20221207185340439

    • Loopback

      image-20221207185406820

    • Link-local IPv6 Address (LLA)

      image-20221207185431202

      • LLA prefix must be fe80::

2. IPv4 vs IPv6 fields

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  • Similar and evolving fields

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  • remove fields

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3. IPv4 vs IPv6 header

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  • IPv6 extension headers

    • Hop by Hop options header.

    • Destination options header.

    • Routing header.

    • Fragment header.

    • Authentication header (AH).

    • Encapsulation security payload (ESP) header.

      封装安全有效载荷（ESP）头。

4. Prefix Terminology

  • Prefix terms

image-20221207192219414

  • IPv6 Relative Network Sizes

image-20221207192243621

  • Prefix assignments

    • Provider Aggregatable (PA) Assignments

    集体提供者（PA）的分配

    • From LIR(Local internet registry) allocation (minimum /32)

    • Register by LIR in RIR(Regional Internet Registry) IRRDB(Internet router registry data base).

    • Provider Independent (PI) Assignments

    独立提供者（PI）的任务

    • Minimum size is /48
    • Cannot be sub-assigned.
    • Exercise:

image-20221207193719288

image-20221207194009495

  • EUI-48 :34ed:8432

  • EUI-64: 36ed:84ff:fe32

  • LLA IPv6 Host ID: fe80::36ed:84ff:fe32

Example

  • EUI-48 to EUI-64

image-20221207194234087

6. Multicast

1. Scope and ground

  • IPv6 multicast flags

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  • IPv6 multicast Scope

image-20221207195424182

image-20221207195440924

image-20221207195516064

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Ff02:: is link local address prefix, which is importance.

  • Multicast Group ID

image-20221207195712549

image-20221207195731971

每个GroupID的含义在Link local

每个GroupID的含义在site local

2. MAC

  • Multicast MAC is associated with each multicast address.

多播MAC与每个多播地址相关。

  • For IPv6 multicast addresses, the last 32 bits of the IPv6 address are OR’d with 33:33:00:00:00.

对于IPv6组播地址，IPv6地址的最后32位与33:33:00:00:00’d

  • Example

image-20221207200301723

Multicast ip address: ff02::1

mac address : 33:33:00:00:00

3. Solicited-Node Multicast Address (SNMA)

Solicited-Node Multicast Address(被请求的节点多播地址)

  • Every device that uses an IPv6 address will also compute and join a SNMA group for each IPv6 address.

每个使用IPv6地址的设备也将为每个IPv6地址计算并加入一个SNMA组。

  • This address is required for the IPv6 NDP(Neighbor Discovery Protocol).

  • Example

image-20221207200818110

  • last 24 bits of Interface ID, interface ID : 32
  • Ff02::1 SNMA

7. IPv6 Assigned Prefixes

  • Address Type indicated by Format Prefix (FP).

由格式前缀（FP）表示的地址类型。

image-20221207201412743

  • Anycast addresses allocated from unicast prefixes.

从单播前缀分配的任播地址。

  • Assigning a unicast address to more than one interface turns a unicast address into an anycast address.

将一个单播地址分配给一个以上的接口，会使单播地址变成任播地址。

  • Exercise

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IPv6 application

  • DHCP(Dynamic Host Configuration Protocol)v6

    • Stateless - > Used with SLAAC(Stateless Address Auto-configuration).
    • Stateful -> Similar to DHCP use in IPv4.

  • DNS(Domain Name System)v6

image-20221207203226594

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  • ICMP(Internet Control Message Protocol)v6
    • Much more important than ICMP
    • Critical to the operation of IPv6.

Neighbour Dicovery(ND)

  • IPv6 Neighbour Discovery (ND)

    • For Nodes

      • Address configuration (SLAAC)
      • Link-layer address resolution
      • Link-layer address change notification
      • Neighbour Unreachability Detection (NUD)

    • For Hosts:

      • Router discovery
      • Parameter discovery (MTU, prefixes, hop limits).

    • For Routers:

      • Advertise their presence & parameters
      • Advertise on-link prefixes
      • Determine next hops
      • Redirect hosts to better next hops.

    • Stateless auto-configuration (SLAAC)

      • Creation of Global Unique Address (GUA)
      • Based in ICMPv6 (ND protocol).
      • Creation of Link-local Address (LLA)
        • Assumes that each interface can provide a unique identifier.
        • Use Duplicate Address Detection (DAD).
        • Plug & play.

    • Stateful auto-configuration

      • Use of Stateful DHCPv6.

SLAAC process

process

  • Host creates a Solicited-Node Multicast Address (SNMA)

  • Host registers a Multicast Listener Report(MLR) for SNMA address to join group

    • from ( :: ) to ff02::16 Multicast Listener Discovery (MLD)

    image-20221207204451342

    左边发送到右边

    • Destination Mac : ::
    • Source Mac: ff02::16

  • Host creates a Link Local Address (LLA)

    • Sends Neighbour Solicitation (NS) (135) from ( :: ) to SNMA with LLA target

    image-20221207210314214

    • Source mac is ::
    • Destination mac is ff02::1:ffaa

    ff02::1 which mean all node on the link local

    • No Neighbour Advertisement (136) is received
    • No duplicate(重复) for LLA detected
    • If Neighbour Advertisement (NA) (136) received auto-configuration stops.

  • Host registers a Multicast Listener Report for SNMA address to join group

    • from LLA to ff02::16 MLD

    image-20221207210759968

    • source mac fe80::200:ff:feaa

    fe80:: link local address

    • Destination mac is ff02::16

    ff02::16 Multicast Listener Discovery (MLD)

  • Host sends Router Solicitation (RS) (133) to ff02::2 ‘All routers’ from LLA

image-20221207211003765

  • Source Mac is fe80::200:ff:feaa
  • Destination Mac is ff02::2

Ff02::2 all router on link local

  • Router sends Router Advertisement (RA) (134) to ff02::1 ‘All nodes’ from its LLA with prefix

image-20221207211235848

  • source Mac : Fe80::200:ff:feaa
  • Destination Mac : ff02::1

ff02::1 all node on link local

  • Host creates Globally Unique Address (GUA) from prefix and MAC
    • Sends NS (135) from ( :: ) to SNMA with GUA target
    • If NA (136) received auto-configuration stops.
  • Finish SLAAC.

RA Flags

如果M标志被设置为0，O标志被设置为1，则使用DHCPv6来获得额外的配置参数。

  • example

M DHCPv6 stateful(有状态)

M and O SLAAC & DHCPv6 stateless(无状态)。

M and O RDNSS(Recursive DNS server), DNSSL(DNS Search List Option)

RDNSS ;DNSSL

LLA&SNMA generation

LLA

  • IPv6 – Neighbor Discovery Protocol (NDP)

image-20221207212249164

  • 第一步检查邻居的缓存表里是否有PC2

    • 如果有，则直接创建Link local frame，然后PC2的MAC address就是目标address
    • 无，则第二步

  • 第二步

    • 发送neighbour discovery (ND) 向PC2询问它的MAC地址
    • Neighbor Request(NR)邻居请求被发送到PC 2的被(SNMA)请求节点组播地址上

  • ff02::1 is SNMA

  • IPv6 – Link Local address (LLA)

image-20221207213814416

  • 一旦为接口分配了IPv6地址（或启用了IPv6），操作系统就会自动分配一个LLA。
  • LLA可以由管理员静态分配。
  • 路由器将不转发以LLA为目的地的数据包。
  • LLA地址fe80::/10 - fe80::eui-64或静态分配fe80::和最重要的64位。- fe80:: 是link local address
  • 静态分配的LLA将优先于自动生成的LLA。
  • Link Local Address (LLA) automatic assignment

image-20221207214200194

  • 第一步，检查带有FF：FE的64 bit
  • 第二步，将EUI-64变回EUI-48, 020c:cffff:fec1 -> 00:0c:cf:c1:26
  • 所以MAC address 是00:0c:cf:c1:26
  • Link Local Address (LLA) Static assignment

image-20221207214740999

SNMA

  • IPv6 – Solicited Node Multicast Address (SNMA)

image-20221207215023117

  • 一个被请求的节点多播地址(SNMA)是通过获取单播或任播地址中最不重要的24位并将其附加到前缀ff02::1:ff00/104来创建的。
  • 每个放在接口上的IPv6地址都会产生一个SNMA。
  • 该接口加入了一个请求节点多播组地址(SNMA)。(它监听以IPv6征求节点多播地址为目的地的流量）。

image-20221207235638858

  • 第一步，找到SNMA
  • 第二步，mac 是33:33:fe:30:96
  • Mapping Solicited Node Multicast Addresses to MAC addresses

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  • PC X performs a ND for PC A

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Question ask

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Question and summary

1. Questions

  • Question 1

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SNMA

image-20221207195731971

  • Destination MAC is 33:33:00:00:00:02 Which means all routers on the Linklocal
  • Source IP is ::
  • Destination IP is ff02::2
  • Router IP link local : fe80::210:ffff:ffd6:58c0
  • Question 2

image-20221208005231463

SNMA, DAD

destination MAC: 33:33:FE:23:47:33

Source address: ::

Destination address: ff02::1:ff:23:4733

  • question 3

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Router advertisement

  • Destination MAC: 33:33:00:00:00:01
  • Source address: fe80::210:ffff:fed6:58c0
  • Destination address: ff02::01
  • source Link-layer address is fe80::210:ffff:fed6:58c0
  • question 4

image-20221208010718243

snma

  • Destination Mac: 33:33:ff:23:47:33
  • source address is fec0:0:0:f282:210:ffff:fed6:58c0 -site local address
  • Destination address is ff02::1:ff:23:47:33
  • Host A IP:fec0::f282:2b0:d0ff:fe23:4733
  • question5

image-20221208012557092

  • Destination MAC is 33:33:ff:23:47:33
  • Source address: 3ff3:2900:d005:f282:210:ffff:fed6:58c0
  • destination address is 3ffe:2900:d0005:f282:2b0:d0ff:fe23:4733

2. Summary:

RA(Router advertisement)

  • Ethernet Header:

MAC 33:33:00:00:00:01

  • IPv6

Source address: fe80:: EUI-64 from route, LLA

Destination address: ff02::1 all node on Link local

source Link layer: fe80:: EUI-64 from router

RS(Router Solicitation)

  • Ethernet Header:

MAC33:33:00:00:00:02

  • IPv6

Source address: fe80:: EUI-64 from router LLA

Destination address: ff02::2

NS(Neighbour Solicitation)

  • Ethernet Header:

MAC :33:33: last 32bit from EUI-64

  • IP v6 if there are DAD(duplicate )ip address process

Source address: ::

Destination address: ff02::1:ff:last24bit from SNMA

  • Ipv6 if there are duplicate ip address process

source address:::

destination address: fe80:: EUI-64

  • ipv6 if host use GUA prefix

Follow that.

3. Cisco Routes

Generate ipv6 LLA:

ipv6 address fe80::1 link-local