312-49 · Question #424
In a virtual test environment, Michael is testing the strength and security of BGP using multiple routers to mimic the backbone of the Internet. This project will help him write his doctoral thesis on
The correct answer is A. The change in the routing fabric to bypass the affected router. When a router in a BGP network fails, other routers will detect the loss of connection and update their routing tables to bypass the affected router.
Question
In a virtual test environment, Michael is testing the strength and security of BGP using multiple routers to mimic the backbone of the Internet. This project will help him write his doctoral thesis on "bringing down the Internet". Without sniffing the traffic between the routers, Michael sends millions of RESET packets to the routers in an attempt to shut one or all of them down. After a few hours, one of the routers finally shuts itself down. What will the other routers communicate between themselves?
Options
- AThe change in the routing fabric to bypass the affected router
- BMore RESET packets to the affected router to get it to power back up
- CSTOP packets to all other routers warning of where the attack originated
- DRESTART packets to the affected router to get it to power back up
How the community answered
(43 responses)- A79% (34)
- B2% (1)
- C12% (5)
- D7% (3)
Why each option
When a router in a BGP network fails, other routers will detect the loss of connection and update their routing tables to bypass the affected router.
Border Gateway Protocol (BGP) neighbors maintain sessions through keepalive messages; if a router fails or becomes unreachable, its neighbors detect the session timeout. They then withdraw the routes learned from that peer and propagate these updates throughout the BGP network, causing other routers to recalculate their best paths and effectively route traffic around the affected device.
Routers do not send 'RESET' packets to a downed router to bring it back online; they adapt to its absence by updating routing information.
There is no standard 'STOP' packet in routing protocols for warning about attack origins; routing protocols focus on advertising and withdrawing route reachability.
Routers do not send 'RESTART' packets to power up a failed device; they adjust their routing based on current network availability and reachability.
Concept tested: BGP router failure response
Source: https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html
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