BPG 2.0 Flashcards
Can MED be configured via redistribution, inbound, and outbound updates?
true
MED must be regenerated when set by an iBGP peer to allow its propagation to an eBGP peer, it can be reset, incremented, or decremented
true
By default, MED is used as a tie-breaker when the same prefix is received from different ASes
false
By default, announcements without MED receive the worst value
false, the best value. This can be changed: bgp bestpath med missing-as-worst
The BGP bestpath med always should be activated only on edge routers
false, it must be consistent throughout the network to avoid loops
What are the 3 types of communities and their lengths?
Standard: 32 bits > 16:16, Extended: 64 bits: 16 type 32:16 or 16:32, Large: 96 bits: 32:32:32
What is the proposed structure for large communities?
32 bits - Source AS > 32 Bits action > 32 bits destination AS
When a route is reflected, the reflector creates the BGP Cluster List attribute and attaches it to the route if it does not exist
true
If the route is received by a route reflector in the same cluster, it will recognize its cluster ID number in the cluster list and accept it
false
The route reflector client sets an extra BGP attribute, called Originator ID
False, the first RR at the moment of reflection. The RR sets the Originator = client that originates the prefix.
The Originator ID does not prevent RR Clients from receiving looped routes
false, it does prevent
Reflected routes are preferred over non-reflected routes.
false, reflected routes are worse than non-reflected routes
Reflected routes with a smaller cluster list are preferred
true, same concept as the AS path
What two attributes are modified by the RR when reflecting the route?
Cluster List and Originator ID
Reflected routes between RRs with the same cluster ID are accepted
false
RR Clients need to have sessions with all RRs in a clustered environment
true, because RRs in a cluster do not exchange routes with each other
It is necessary for the client to have sessions with RRs from different clusters
false, the Client must have sessions only with all RRs of a single cluster to avoid receiving duplicate routes
In intraconfed eBGP sessions, the AS Path is not modified
false, it is modified
In intraconfed iBGP sessions, the AS Path is not modified
true
In intraconfed sessions, the BGP process uses the Public AS
false, private
In intraconfed sessions, what command identifies the Public AS?
bgp confederation identifier {{public_as}}
In intraconfed sessions, what command identifies the private ASes with which sessions should be accepted?
bgp confederation peer {{private_as1}} {{private_as2}}
There is no need for eBGP multihop in intraconfed eBGP sessions
false, it is necessary if the peer is not directly connected
A migration to confederation can be done gradually
false, all routers need to be reconfigured
In intraconfed sessions, there is no need to list the AS of the process as bgp confed peer
true
In IOS XR, what is the commit best-effort command used for?
Apply only the valid part of the configuration, ignoring errors
BGP Prefix Limit is enabled by default in all Cisco systems
false, only in IOS-XR
What is the neighbor limit for IOS XR?
4000
What are the possible actions and the default when a peer exceeds the number of prefixes?
Possible actions: warning only and cease peering, default is cease. IOS XR also has discard-extra-paths, IOS XE does not
What feature is equivalent to soft configuration inbound?
route refresh
What is the difference between route-refresh and soft reconfiguration inbound?
soft reconfiguration creates a database per neighbor, route refresh does not
Feature that allows informing the neighbor which prefixes will be filtered so that such prefixes are not sent
Outbound route filter, neighbor 10.0.255.9 capability orf prefix-list both
Consider a router without a peer group with 150k routes and 3 peers, how many NRLIs should be generated?
450k
