Which attribute must exist in the BGP update packet? Select the best response.
A.
LOCAL_ PREF
B.
AGGREGATOR
C.
AS_Path
D.
Weight
Explanation:
Origin, AS_Path, Next_Hop are well-known mandatory BGP attributes that all BGP Updates
must include.
Note:
There are 4 BGP attribute types:
+ Well-known Mandatory: recognized by all implementations of BGP and mustappear in a
BGP update message. If missing, a notification error will be generated.
+ Well-Known Discretionary: recognized by all implementations of BGP but may not be
sent in the BGP update message (include LOCAL_PREF,ATOMIC_AGGREGATOR).
+ Optional Transitive: may or may not be recognized by all BGP implementations.
Because the attribute is transitive, BGP accepts and advertises the attribute even if it is not
recognized (include Community attribte).
+ Optional Nontransitive: may or may not be recognized by all BGP implementations.
Whether or not the receiving BGP router recognizes the attribute, it is nontransitive and is
not passed along to other BGP peers (include MED).