在Path后面的“i”表示路由条目是通过network命令发布的，如果是“？”则表明路由条目是通过redistribute命令再分发的。当想要改变汇聚路由条目的属性时，要使用attribute-map/route-map参数

Rainier
route-map ATT permit 10
set origin incomplete
router bgp 852
aggregate-address 194.69.12.0 255.255.252.0 attribute-map ATT

R2
conf t
int s2/0
ip ad 85.122.8.6 255.255.255.248
encap f
no arp f
no frame inver
frame map ip 85.122.8.5 201 b
no shut
int s2/1
ip ad 85.122.8.10 255.255.255.248
encap f
no arp f
no frame inver
frame map ip 85.122.8.9 213 b
no shut
router bgp 852
no au
no sy
nei 85.122.8.5 remote 7519
nei 85.122.8.9 remote 7518
end

 

R3
conf t
int l 0
ip ad 194.69.12.1 255.255.255.0
int l 1
ip ad 194.69.13.1 255.255.255.0
int l 2
ip ad 194.69.14.1 255.255.255.0
int l 3
ip ad 194.69.15.1 255.255.255.0
int s 2/1
ip ad 85.122.8.9 255.255.255.248
encap f
no arp f
no frame inver
frame map ip 85.122.8.10 312 b
no shut
router bgp 7518
no au
no sy
nei 85.122.8.10 remote 852
net 194.69.12.0 mask 255.255.255.0
net 194.69.13.0 mask 255.255.255.0
net 194.69.14.0 mask 255.255.255.0
net 194.69.15.0 mask 255.255.255.0
end

 

 

先在R3上的194.69.13.0/24条目上配置BGP团体属性no-expert，
R2
access-list 100 permit ip host 194.69.13.0 host 255.255.255.0
route-map ADV permit 10
match ip ad 100
set community no-export
route-map ADV permit 20
router bgp 852
nei 85.122.8.5 route-map ADV out
nei 85.122.8.5 send-community

 

在R1上BGP表的状态
R1#sh ip bgp
BGP table version is 18, local router ID is 85.122.8.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 194.69.12.0      85.122.8.6                             0 852 7518 i
*> 194.69.14.0      85.122.8.6                             0 852 7518 i
*> 194.69.15.0      85.122.8.6                             0 852 7518 i
因为194.69.13.0被加入了no-export属性，所以不会发送到R1上，

 

 

在R2上做路由汇聚
router bgp 852
aggregate-address 194.69.12.0 255.255.252.0 summary-only as-set
这时R1的BGP表状态
R1#sh ip bgp

 

R1#
由于汇聚路由继承了具体路由条目的no-export团体属性，所以在R1上的BGP表是空的，

R2
access-list 1 deny 194.69.13.0
access-list 1 permit any
route-map to_R1 permit 10
match ip ad 1
router bgp 852
aggregate-address 194.69.12.0 255.255.252.0 summary-only as-set advertise-map to_R1

这时在R1上观察BGP表的状态
R1#sh ip bgp      
BGP table version is 34, local router ID is 85.122.8.5
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 194.69.12.0/22   85.122.8.6               0             0 852 7518 i
R1收到R2发送的汇聚路由。

R2(config-router)#do sh ip bgp communi no-export
BGP table version is 47, local router ID is 85.122.8.10
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
s> 194.69.13.0      85.122.8.9               0             0 7518 i
R2上具有no-export团体属性的条目只有194.69.13.0