An engineer is trying to implement BGP in a multihomed architecture. What must the engineer configure to influence inbound path selection?
An engineer is trying to implement BGP in a multihomed architecture. What must the engineer configure to influence inbound path selection?
To influence inbound path selection in BGP for a multihomed architecture, the engineer should configure a route map with the AS-PATH attribute. The AS-PATH attribute allows the engineer to prepend their AS number multiple times to make a path less attractive to inbound traffic from external sources. This method effectively directs traffic to follow a desired path by manipulating the AS path length, which is a key factor in BGP's path selection process.
It is A. Please read https://community.cisco.com/t5/other-network-architecture/bgp-weight-or-as-path-prepend/td-p/184082
A is correct, weight only influences outbound traffic. Setting AS path prepend when advertising prefixes out to neighbour influences inbound traffic
A is the correct answer. BGP can influence inbound path selection using one of the following BGP attributes: 1. AS-path 2. Multi-Exit Discriminator (MED) Influencing Inbound Path Selection by Modifying the AS_PATH Attribute: router bgp 40000 neighbor 192.168.1.2 remote-as 45000 ! address-family ipv4 neighbor 192.168.1.2 activate neighbor 192.168.1.2 route-map PREPEND out ! route-map PREPEND permit 10 set as-path prepend 40000 40000 https://content.cisco.com/chapter.sjs?uri=/searchable/chapter/content/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-3e/irg-iproute-bgp-xe-3e-book/irg-prefix-filter.html.xml
Sorry, I didn't pay enough attention to answer D. D is totally excluded, because the Weight controls the outbound traffic, not the inbound. The correct answer is A
As many other questions, cisco tries to makes these questions more stupid instead of more difficult. It is not clear if question is about inbound traffic or inbound bgp routes. If is about inbound traffic (inbound traffic path), then A is correct If it is about inbound BGP updates (received BGP routes with multiple next-hops or paths), then D is correct
A is incorrect. D is the correct answer. WEIGHT attribute is used to define the path selection process.
LOLz for traffic OUTBOUND...
Weight attribute is used to influence "Outbound" traffic, not "Inbound". "AS Path prepending" feature is used to make one route preferred or less preferred, so ISPs can make forwarding decisions when sending the traffic to us (inbound traffic from our perspective). "A", is definitely correct.