交换机BGP使能ipv6地址族时导致ipv4邻居中断

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交换机BGP使能ipv6地址族时导致ipv4邻居中断

1、我司设备在ipv6单播地址族时支持6PE功能，即IPv4邻居可以承载IPv6路由信息。

2、同一个ipv4 bgp邻居,处于ESTABLISHED状态的情况下，该邻居使能IPv6地址族能力，BGP需要重新发送OPEN报文以协商BGP能力，根据RFC状态机规定，需要重新切换状态机从IDLE->CONNECT->OPEN->ESTABLISHED。

3、因此当IPv4邻居在配置组并且在IPv6地址族下使能该配置组，从配置含义上认为该配置组里的IPv4邻居也是要承载IPv6路由信息的，因此需要断开邻居重新协商支持的地址族能力。   

H3C：

address-family ipv6 unicast

 balance 128

 preference 20 200 10

 peer HBHL-SUPER_CORE-A enable --------peer enable的时候会重建邻居

 peer HBHL-SUPER_CORE-B enable

 peer HBHL-SUPER_CORE-C enable

HW：

#                                                                                                                                              

bgp 100                                                                                                                                       

 group ebgp external

peer ebgp as-number 200

peer 10.0.0.2 as-number 200

 peer 10.0.0.2 group ebgp      -----------------配置该命令后，上面黄色配置自动添加。

peer 2001:10::2 as-number 200

peer 2001:10::2 group ebgp

#

ipv4-family unicast

  peer ebgp enable   -------------配置该命令后，下面两个黄色配置自动添加。

  peer 10.0.0.2 enable

  peer 10.0.0.2 group ebgp  

 #

ipv6-family unicast

  peer 2001:10::2 enable  

  peer ebgp enable   ------------单配置这条命令，ipv6邻居无法建立，需要手工配置上面具体peer才行，配置后也会重建邻居

#

cisco：

router bgp 200                                                                                                                                 

  router-id 10.0.0.2                                                                                                                          

  address-family ipv4 unicast                                                                                                                  

  template peer ebgp                                                                                                                          

    remote-as 100                                                                                                                              

    address-family ipv4 unicast                                                                                                               

      send-community both                                                                                                                      

      weight 10                                                                                                                               

    address-family ipv6 unicast   ----------在template peer中增加ipv6地址族，会造成已有的ipv4邻邻居重建                                                                                                     

  neighbor 10.0.0.1                                                                                                                            

inherit peer ebgp

后续绑定neighbor时候，不会震荡

  neighbor 2001:10::1

    inherit peer ebgp

测试使能其他地址族也是一样的

[host-bgp-default-vpnv4]peer 112.1.1.254 enable

*Jan 15 06:28:43:820 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ManualStop event in ESTABLISHED state.

*Jan 15 06:28:43:820 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Send NOTIFICATION

 Err/SubErr: 6/6 (Cease/Other Configuration Change)

 Error data NULL.

*Jan 15 06:28:43:820 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 State is changed from ESTABLISHED to IDLE.

%Jan 15 06:28:43:821 2011 host BGP/5/BGP_STATE_CHANGED:

 BGP.: 112.1.1.254 state has changed from ESTABLISHED to IDLE for other configuration change.

*Jan 15 06:28:45:611 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ConnectRetryTimer_Expires event in IDLE state.

*Jan 15 06:28:45:611 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ManualStart event in IDLE state.

*Jan 15 06:28:45:612 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 State is changed from IDLE to CONNECT.

*Jan 15 06:28:45:613 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive Tcp_CR_Acked event in CONNECT state.

*Jan 15 06:28:45:613 2011 host BGP/7/DEBUG:

 BGP.: Connected to 112.1.1.254.

*Jan 15 06:28:45:613 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 State is changed from CONNECT to OPENSENT.

*Jan 15 06:28:45:615 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ReceiveOpenMessage event in OPENSENT state.

*Jan 15 06:28:45:615 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 State is changed from OPENSENT to OPENCONFIRM.

*Jan 15 06:28:45:616 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ReceiveKeepAliveMsg event in OPENCONFIRM state.

*Jan 15 06:28:45:616 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 State is changed from OPENCONFIRM to ESTABLISHED.

%Jan 15 06:28:45:616 2011 host BGP/5/BGP_STATE_CHANGED:

 BGP.: 112.1.1.254 State is changed from OPENCONFIRM to ESTABLISHED.

*Jan 15 06:28:46:321 2011 host BGP/7/DEBUG:

 BGP.: 112.1.1.254 Receive ReceiveUpdateMsg event in ESTABLISHED state.   

当前主要设备厂商均是如此实现。