SOURCECODEBD.NET

Live Experience

11. COMMUNITY ATTRIBUTE

HOW TO COMMUNITY ATTRIBUTE CONFIGURATION
 
Interface IP Address Configuration 
 
R1 
 
Interface  IP Address   Subnet Mask 
S 0            1.1.1.1          255.0.0.0 
E 0           10.1.1.1        255.0.0.0 
 
R2 
 
Interface  IP Address   Subnet Mask 
S 0           3.3.3.1           255.0.0.0 
S 1           1.1.1.2           255.0.0.0 
S 2           2.2.2.1           255.0.0.0 
E 0           20.1.1.1         255.0.0.0 
  
R3 
 
Interface  IP Address   Subnet Mask 
S 0            2.2.2.2          255.0.0.0 
E 0           30.1.1.1        255.0.0.0 
 
R4 
 
Interface  IP Address   Subnet Mask 
S 0           3.3.3.2           255.0.0.0 
E 0          40.1.1.1         255.0.0.0 
 
 
Task 1: 
 
Configure BGP on all the routers. Configure R1, R2 and R4 in AS 100. Configure R3 in 
AS 200. Network 10.0.0.0 should not be sent ouside AS 100 using no-export community 
attribute. 
 
R1 
 
Access-list 1 permit 10.0.0.0 
0.255.255.255 
 
Route-map no-exp 
Match ip add 1 
Set community no-export 
 
Router bgp 100 
Neighbor 1.1.1.2 route-map no-exp out 
Neighbor 1.1.1.2 send-community
 
 
Verification: 
 
R3#show ip route 
 
The output does not display network 10.0.0.0 in the routing table as it is blocked by the 
no-export community attribute. 
 
R2#show ip bgp 10.0.0.0
 
The output displays the community attribute no-export set . 
 
Task 2: 
 
Configure BGP on all the routers. Configure R1, R2 and R4 in AS 100. Configure R3 in 
AS 200. Network 10.0.0.0 should not be advertised to any peers, internal or external. 
 
R1 
 
Access-list 1 permit 10.0.0.0 
0.255.255.255 
 
Route-map no-adv 
Match ip add 1 
Set community no-advertise 
 
Router bgp 100 
Neighbor 1.1.1.2 route-map no-adv out 
Neighbor 1.1.1.2 send-community 
 
Verification: 
 
R3#show ip route
R4#show ip route
 
The output doesn’t display network 10.0.0.0 in the routing table of both ibgp and ebgp 
neighbors. 
 
R2#show ip bgp 10.0.0.0
 
The output displays the community attribute no-advertise set.
You are here: Home / BGP / HOW TO COMMUNITY ATTRIBUTE CONFIGURATION