8.3 IGMPv2

1.基本概念

IGMPv2定义四种报文：

1）成员关系查询

分常规查询报文（目的IP地址为224.0.0.1）和特定组查询（成员离开组播组时会发送一个离组报文，查询器发送特定查询报文进行查询，目的地址为所查询的组播地址，“组地址”字段记录这个组播地址）

2）成员关系报告

主机加入组播组或进行常规查询时，主机发送成员关系报告报文，目的地址为主机所加入的组播地址，“组地址”字段记录这个组播地址）

3）离组

主机离开组播组时，会主动发送离组报文，目的地址224.0.0.2，“组地址”字段记录这个组播地址）

4）版本1成员关系报告

用于兼容IGMPv1。

2.IGMPv2查询及响应

IGMPv2定义自己的查询器选举机制（IGMPv1通过PIM用来选举产生DR），IGMPv2查询最大响应时间缺省10s。

3.IGMPv2组成员离开

与IGMPv1组成员默默离开不同，IGMPv2成员会主动发送离组报文，离组目的IP地址为224.0.0.2，报文“组地址”值为离组主机地址。

4.IGMPv2查询器

网段中接口IP地址最小的路由器成为该网段的IGMPv2查询器，负责向这个网段执行查询操作。

5.IGMPv2基础配置

1）R1配置

[R1]multicast routing-enable 
[R1]interface GigabitEthernet 0/0/0
[R1-GigabitEthernet0/0/0]IP address 192.168.10.252 24
[R1-GigabitEthernet0/0/0]igmp enable 
[R1-GigabitEthernet0/0/0]igmp version 2

2）R2配置

[R2]multicast routing-enable 
[R2]interface GigabitEthernet 0/0/0
[R2-GigabitEthernet0/0/0]ip address 192.168.10.253 24
[R2-GigabitEthernet0/0/0]igmp enable 
[R2-GigabitEthernet0/0/0]igmp version 2

3）查询igmp信息

<R1>display igmp interface
Interface information of VPN-Instance: public net 
 GigabitEthernet0/0/0(192.168.10.252): 
   IGMP is enabled
   Current IGMP version is 2
   IGMP state: up
   IGMP group policy: none
   IGMP limit: -
   Value of query interval for IGMP (negotiated): -
   Value of query interval for IGMP (configured): 60 s
   Value of other querier timeout for IGMP: 0 s
   Value of maximum query response time for IGMP: 10 s
   Querier for IGMP: 192.168.10.252 (this router)

<R2>display igmp interface 
Interface information of VPN-Instance: public net 
 GigabitEthernet0/0/0(192.168.10.253): 
   IGMP is enabled
   Current IGMP version is 2
   IGMP state: up
   IGMP group policy: none
   IGMP limit: -
   Value of query interval for IGMP (negotiated): -
   Value of query interval for IGMP (configured): 60 s
   Value of other querier timeout for IGMP: 121 s
   Value of maximum query response time for IGMP: 10 s
   Querier for IGMP: 192.168.10.252 

4）查询igmp组信息

[R1]display igmp group 
Interface group report information of VPN-Instance: public net 
 GigabitEthernet0/0/0(192.168.10.252): 
  Total 2 IGMP Groups reported
   Group Address   Last Reporter   Uptime      Expires     
   239.1.1.1       192.168.10.3    00:11:18    00:01:57    
   239.1.1.2       192.168.10.2    00:10:35    00:01:57  

5）配置静态组播组

[R1-GigabitEthernet0/0/0]igmp static-group 239.1.1.2
[R1]display igmp group static
Static join group information of VPN-Instance: public net 
 Total 1 entry, Total 1 active entry
  Group Address   Source Address  Interface             State     Expires     
  239.1.1.2       0.0.0.0         GE0/0/0               UP        never 

6）配置静态组播组指定组播源

[R1-GigabitEthernet0/0/0]igmp static-group 239.1.1.2 source 172.16.2.1 
[R1]display igmp group static                    
Static join group information of VPN-Instance: public net 
 Total 1 entry, Total 1 active entry
  Group Address   Source Address  Interface             State     Expires     
  239.1.1.2       172.16.2.1      GE0/0/0               UP        never