RFC4007: IPv6 Scoped Address Architecture¶
Category: Standards Track
March 2005
Updated by: 7346
Abstract¶
This document specifies the architectural characteristics, expected behavior, textual representation, and usage of IPv6 addresses of different scopes.
1. Introduction¶
This document specifies the architectural characteristics, expected behavior, textual representation, and usage of IPv6 addresses of different scopes.
This document intentionally focuses on link-local and multicast scopes only.
4. Address Scope¶
For unicast scopes, link-local is a smaller scope than global.
For multicast addresses, there are fourteen possible scopes, ranging from interface-local to global.
For multicast scopes, scopes with lesser values in the “scop” subfield of the multicast address are smaller than scopes with greater values, with interface-local being the smallest and global being the largest.
5. Scope Zones¶
A scope zone, or simply a zone, is a connected region of topology of a given scope. For example, the set of links connected by routers within a particular (multicast) site, and the interfaces attached to those links, comprise a single zone of multicast site-local scope.
Scope Zones用于定义IPv6地址的范围，决定其在特定网络环境中的可见性和可访问性。
6. Zone Indices¶
Zone Indices are used to identify the scope zone of an IPv6 address.
Zone Indices Example:
| /--------------------site1--------------------\ /--site2--\ | | | | /-------------------admin1--------------------\ /-admin2--\ | | | | /--link1--\ /--------link2--------\ /--link3--\ /--link4--\ | | | | /--intf1--\ /--intf2--\ /--intf3--\ /--intf4--\ /--intf5--\ | --------------------------------------------------------------- : | | | | : | | | | : | | | | (imaginary ================= a point- a loopback an Ethernet to-point tunnel link) link
7. Sending Packets¶
发送具有范围地址的IPv6数据包的过程类似于发送常规IPv6数据包的过程，但需要额外关注地址范围和下一跳选择。
8. Receiving Packets¶
IPv6接收具有范围地址的数据包的过程需要接收节点对地址范围、区域索引和附加标头进行适当的处理和判断，以确保数据包能够正确到达目标节点并被正确处理。
9. Forwarding¶
IPv6数据包转发的过程涉及路由器维护路由表、识别目标地址和下一跳路由器、根据地址范围和区域索引选择正确的下一跳路由器，以及处理转发过程中可能出现的错误或异常情况。
10. Routing¶
IPv6路由选择和配置涉及静态和动态路由协议的选择和部署，以及路由选择算法和路由表的管理。
11. Textual Representation¶
To specify an IPv6 non-global address without ambiguity, an intended scope zone should be specified as well:
<address>%<zone_id>
其中:
<address> is a literal IPv6 address,
<zone_id> is a string identifying the zone of the address, and
`%` is a delimiter character to distinguish between <address> and <zone_id>.
在IPv6地址的文本表示形式中，<zone_id>部分可以用不同的方式表示，具体取决于操作系统和应用程序。在某些操作系统中，<zone_id>部分被表示为接口名或接口索引号；在其他操作系统中，<zone_id>部分可能是数字、字母或其他符号。
在IPv6地址的文本表示形式中，<zone_id>部分通常用百分号（%）分隔。例如，fe80::1%eth0是一个链路本地地址，其中eth0是接口名称。
Examples¶
The following addresses:
fe80::1234 (on the 1st link of the node)
ff02::5678 (on the 5th link of the node)
ff08::9abc (on the 10th organization of the node)
would be represented as follows:
fe80::1234%1
ff02::5678%5
ff08::9abc%10
If we use interface names as <zone_id>, those addresses could also be represented as follows:
fe80::1234%ne0
ff02::5678%pvc1.3
ff08::9abc%interface10