OSPF, BGP, and Route Manipulation Flashcards
What is BGP router filtering used for?
advertise or reflect routers to clients that get redistributed or for access to certain parts of the network
What is BGP Multi path Load Sharing used for?
Load balancing of external BGP and internal BGP paths networks configured to use MPLS VPNs
What is a totally stubby area in OSPF?
send out just a single LSA for the default route
Which BGP path influences outbound traffic flow from a single router configured locally?
Weight
What’s the difference using weight vs local preference in BGP?
Weight is configured locally and not exchanged in BGP updates
Local Preference is exchanged between iBGP peers and configured at the gateway router.
What two sub-commands can you use to allow eBGP routers to accept routes from the same AS?
allow-as
as-override
What three options that influence outbound routing decisions?
weight and local preference | (AS-path length)
What three options influence inbound routing decisions?
BGP communities and MED | (AS-path length)
What is Policy Based Routing (PBR) used for?
modify a next hop IP address based on a source address
What is AS Path prepending?
Manipulate and extend the AS-Path length of a prefix advertisement in a BGP route by adding additional AS numbers into the AS Path of an advertised prefix.
How does AS Path prepending influence inbound path selection?
Making path appear to be longer and less preferable to BGP
What is used to prevent multiple internet service providers from preventing advertisements of private addresses and addresses that out of scope of the domain?
Route filtering
What is bidirectional forward detection (BFD) designed for?
provide fast forwarding path failure detection notices to routing protocols to greatly reduce overall network convergence time
What is a stub area in OSPF what LSA types are blocked and not allowed in that area?
all type 5 external LSAs (E1 and E2 routes)
