First, the experimental topology:
Second, the experimental requirements:
1, R4, R1, R3, R2 respectively in the BGP process deployment neighbor Send Community attribute command;
2, R4 deployment ACL crawl 4.4.4.4 traffic, route-map named PL, call ACL, set community no-advertise, and invoke Route-map pl out in the BGP process;
3. Verify: View R1 in 4.4.4.4 Item details Are you carrying: no-advertise, and do not pass this route entry to R3, R2?
Third, command deployment:
1, R4, R1, R3, R2 deploy neighbor Send Community attribute command under BGP process respectively
R1 (config) #router BGP 65001
R1 (config-router) #neighbor 3.3.3.3 send-community
R3 (config) #router BGP 65001
R3 (config-router) #neighbor 2.2.2.2 send-community
R4 (config) #router BGP 4
R4 (config-router) #neighbor 14.1.1.1 send-community
R4 (config) #access-list permit 4.4.4.0 0.0.0.255
R4 (config) #route-map PL Permit 10
R4 (config-route-map) #match IP address 10
R4 (config-route-map) #set Community no-advertise
R4 (config) #route-map PL Permit 1000
R4 (config) #router BGP 4
R4 (config-router) #neighbor 14.1.1.1 Route-map Pl out
Four, verify:
R1#show IP BGP 4.4.4.4
14.1.1.4 from 14.1.1.4 (4.4.4.4)
Origin IGP, Metric 0, Localpref, valid, external, best
Community:no-advertise
R3#show IP BGP
R2#show IP BGP
Conclusion: R1 carries the no-advertise attribute and does not pass the 4.4.4.4 Route entry to R2, R3
49-Advanced Routing: BGP Community properties: no-advertise