JunOS使用iBGP路由而不是OSPF路由

Question

你好，我有一个问题，我的Juniper路由器没有向邻居宣传BGP 10.255.255.4/32，因为在inet.0中，它不是作为最佳路由发布的。

root# run show route table inet.0 

inet.0: 11 destinations, 12 routes (11 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.2.0/30        *[IS-IS/15] 2d 22:48:54, metric 20
                    > to 10.0.2.5 via em1.0
10.0.2.4/30        *[Direct/0] 2d 22:49:21
                    > via em1.0
10.0.2.6/32        *[Local/0] 2d 22:49:21
                      Local via em1.0
10.0.3.0/24        *[Direct/0] 2d 22:49:21
                    > via em0.0
10.0.3.1/32        *[Local/0] 2d 22:49:21
                      Local via em0.0
10.255.255.1/32    *[BGP/170] 02:19:00, MED 0, localpref 100, from 10.255.255.2
                      AS path: I, validation-state: unverified
                    > to 10.0.2.5 via em1.0, Push 300
10.255.255.2/32    *[IS-IS/15] 2d 22:48:54, metric 30
                    > to 10.0.2.5 via em1.0
10.255.255.3/32    *[Direct/0] 2d 22:49:21
                    > via lo0.0
10.255.255.4/32    *[OSPF/10] 2d 22:49:06, metric 1
                    > to 10.0.3.2 via em0.0
                    [BGP/170] 00:00:08, localpref 100, from 10.255.255.4
                      AS path: I, validation-state: unverified
                    > to 10.0.3.2 via em0.0
224.0.0.2/32       *[LDP/9] 2d 22:49:21, metric 1
                      MultiRecv
224.0.0.5/32       *[OSPF/10] 2d 22:49:24, metric 1
                      MultiRecv

[edit]
root# 

我目前正在寻找一个解决方案，这将使BGP路线首选。可悲的是，我试着用没有运气的政策声明。

有什么想法吗？先谢谢你

Answer 1

我通过以下政策声明解决了这一问题：

policy-statement prioritize_BGP {
        from {
            route-filter 10.255.255.4/32 exact;
        }
        then {
            preference 10;
            accept;
       }
}

bgp {
        group ibgp {
            import prioritize_BGP;
        }
    }

此解决方案只会调整BGP的确切路径，最终比OSPF更好。

root> show route table inet.0 

inet.0: 11 destinations, 12 routes (11 active, 1 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

10.0.2.0/30        *[IS-IS/15] 3d 08:58:47, metric 20
                    > to 10.0.2.5 via em1.0
10.0.2.4/30        *[Direct/0] 3d 08:59:14
                    > via em1.0
10.0.2.6/32        *[Local/0] 3d 08:59:14
                      Local via em1.0
10.0.3.0/24        *[Direct/0] 3d 08:59:14
                    > via em0.0
10.0.3.1/32        *[Local/0] 3d 08:59:14
                      Local via em0.0
10.255.255.1/32    *[BGP/170] 09:53:18, MED 0, localpref 100, from 10.255.255.2
                      AS path: I, validation-state: unverified
                    > to 10.0.2.5 via em1.0, Push 201, Push 300(top)
10.255.255.2/32    *[IS-IS/15] 3d 08:58:47, metric 30
                    > to 10.0.2.5 via em1.0
10.255.255.3/32    *[Direct/0] 3d 08:59:14
                    > via lo0.0
10.255.255.4/32    *[BGP/10] 00:24:52, localpref 100, from 10.255.255.4
                      AS path: I, validation-state: unverified
                    > to 10.0.3.2 via em0.0
                    [OSPF/10] 3d 08:58:59, metric 1
                    > to 10.0.3.2 via em0.0
224.0.0.2/32       *[LDP/9] 3d 08:59:14, metric 1
                      MultiRecv
224.0.0.5/32       *[OSPF/10] 3d 08:59:17, metric 1
                      MultiRecv

root> 

Answer 2

查看您的输出，您不能重新广告BGP路由的原因是因为它不是活动的/首选的。您可以调整OSPF的偏好，使其比BGP更少：

set protocols ospf preference 180

但是，您需要理解的是，所讨论的BGP路由依赖于底层OSPF下一跳作为递归的下一跳可用-例如:您的IBGP会话终止在环回10.255.255.4，这是您通过OSPF学习的。如果您改变了OSPF的偏好，您的BGP会话可能会在通过BGP而不是OSPF学习后立即被拆除。

也许你能描述一下你想要解决的问题？