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Topic starter
10/10/2022 7:13 pm
Refer to the exhibit.
The network administrator has configured the Customer Edge router (AS 64511) to send only summarized routes toward ISP-1 (AS 100) and ISP-2 (AS 200).
router bgp 64511
network 172.16.20.0 mask 255.255.255.0
network 172.16.21.0 mask 255.255.255.0
network 172.16.22.0 mask 255.255.255.0
network 172.16.23.0 mask 255.255.255.0
aggregate-address 172.16.20.0 255.255.252.0
After this configuration. ISP-1 and ISP-2 continue to receive the specific routes and the summary route .
Which configuration resolves the issue?
- A . router bgp 64511
aggregate-address 172.16.20.0 255.255.252.0 summary-only - B . router bgp 64511
neighbor 192.168.100.1 summary-only
neighbor 192.168.200.2 summary-only - C . interface E 0/0
ip bgp suppress-map BLOCK_SPECIFIC
!
interface E 0/1
ip bgp suppress-map BLOCK_SPECIFIC
!
ip prefix-list PL_BLOCK_SPECIFIC
permit 172.16.20.0/22 ge 24
!
route-map BLOCK_SPECIFIC permit 10
match ip address prefix-list PL_BLOCK_SPECIFIC - D . ip prefix-list PL_BLOCK_SPECIFIC
deny 172.16.20.0/22 ge 22
ip prefix-list PL BLOCK SPECIFIC
permit 172.16.20.0/22
!
route-map BLOCK_SPECIFIC permit 10
match ip address prefix-list PL_BLOCK_SPECIFIC
!
router bgp 64511
aggregate-address 172.16.20.0 255 255.252.0 suppress-map BLOCKSPECIFIC
Suggested Answer: A
Explanation:
When the aggregate-address command is used within BGP routing, the aggregated address is advertised, along with the more specific routes. The exception to this rule is through the use of the summary-only command. The “summary-only” keyword suppresses the more specific routes and announces only the summarized route.
Explanation:
When the aggregate-address command is used within BGP routing, the aggregated address is advertised, along with the more specific routes. The exception to this rule is through the use of the summary-only command. The “summary-only” keyword suppresses the more specific routes and announces only the summarized route.