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Chapter 7
BGP's Basic Components
D. The Internet Assigned Numbers Authority (IANA) is responsible
for delegating autonomous system numbers. Other organizations
may assign numbers, but only if they are authorized by the IANA.
B. An autonomous systems number is 16 bits long and can range
from 1 through 65,535.
D. In a stub network, there is one entry and exit point. In this type of
network, it is recommended that you not use BGP but use a static
route instead.
B. This peer is in the Connection state until a message is sent to iden-
tify each peer. When the connection is established, it transitions to the
Open state. Once the other peer accepts the connection, the peer tran-
sitions to Established state. If the connection is lost, possibly due to a
version mismatch, the peer goes to the Active state and actively tries to
reestablish the connection using the proper version properties.
B. An UPDATE message is used to advertise topology updates and
changes, including added or withdrawn routes.
A. A well-known mandatory attribute is known to all versions of
BGP and must be included in an UPDATE message.
B. The COMMUNITIES attribute is an optional transitive attribute,
which means that it is not required but, if included, can traverse more
than one AS.
B. MULTI_EXIT_DISCRIMINATOR (MED) is considered to be
BGP's extensive route-selection component. The ORIGINATOR_ID
attribute identifies a router that first advertised a route. The
CLUSTER_LIST attribute is used to detect updates that can cause data
loops. The AS_PATH attribute makes BGP a path-vector protocol by
logging all the autonomous systems a message has traveled through.
C. The NLRI field shows route prefixes with attributes identified in
the Total Path Attributes field. The other answers listed are all
attributes found in the Total Path Attributes field.
Copyright ©2001 SYBEX , Inc., Alameda, CA