[单项选择]

BGP is an inter-autonomous system routing protocol; it is designed to be used between multiple autonomous ___40___. BGP assumes that routing within an autonomous system is done by an intra-autonomous system routing protocol. BGP does not make any assumptions about intra-autonomous system ___41___ protocols employed by the various autonomous systems. Specifically, BGP does not require all autonomous systems to run the same intra-autonomous system routing protocol.
BGP is a real inter-autonomous system routing protocol. It imposes no constraints on the underlying Internet topology. The information exchanged via BGP is sufficient to construct a graph of autonomous systems connectivity from which routing loops may be pruned and some routing. ___42___ decisions at the autonomous system level may be enforced.
The key feature of the protocol is the notion of Path Attributes. This feature provides BGP with flexibility and expandability. Path ___43___ are partitioned into
A. routing 
B. switching 
C. transmitting 
D. receiving

BGP is an inter-autonomous system routing protocol; it is designed to be used between multiple autonomous ___40___. BGP assumes that routing within an autonomous system is done by an intra-autonomous system routing protocol. BGP does not make any assumptions about intra-autonomous system ___41___ protocols employed by the various autonomous systems. Specifically, BGP does not require all autonomous systems to run the same intra-autonomous system routing protocol.
BGP is a real inter-autonomous system routing protocol. It imposes no constraints on the underlying Internet topology. The information exchanged via BGP is sufficient to construct a graph of autonomous systems connectivity from which routing loops may be pruned and some routing. ___42___ decisions at the autonomous system level may be enforced.
The key feature of the protocol is the notion of Path Attributes. This feature provides BGP with flexibility and expandability. Path ___43___ are partitioned into
A. routers 
B. systems 
C. computers 
D. sources

The Border Gateway Protocol (BGP) is an interautonomous system (76) protocol. The primary function of a BGP speaking system is to exchange network (77) information with other BGP system. This network reachability information includes information on the list of Autonomous System (ASs) that reachability information traverses. BGP-4 provides a new set of mechanisms for supporting (78) interdomain routing. These mechanisms include support for advertising an IP (79) and eliminate the concept of network class within BGR BGP-4 also introduces mechanisms that allow aggregation of routes, including. (80) of AS paths. These changes provide support for the proposed supernettting scheme.

Border Gateway Protocol(BGP) is inter-autonomous system (96) protocol. BGP is based on a routing method called path vector routing. Distance vector routing is not a good candidate for inter-autonomous system routing because there are occasions on which the route with the smallest (97) count is not the preferred route. For example, we may not want a packet through an not secure even though it is the shortest route. Also, distance vector routing is unstable due to the fact that the routers announce only the number of hop counts to the destination without actually defining the path that leads to that (98) . A router that receives a distance vector advertisement packet may be fooled if the shortest path is actually calculated through the receiving router itself. Link (99) routing is also not a good candidate for inter-autonomous system routing because an Internet is usually too big for this routing method. To use link state routing for the whole int
A. routing
B. switching
C. transmitting
D. receiving

OSPF routing protocol typically runs over （）.

OSPF is a link-state routing protocol. It is designed to be run internal to a single (1) system. Each OSPF router maintains an identical(2) describing the autonomous system's topology. From this database, a routing table is calculated by constructing a shortest-path (3).OSPF recalculates routes quickly in the face of topological changes, utilizing aminimum of routing (4) traffic. OSPF provides support for equal-cost multipath. An area routing capability is provided, enabling.an additional level of routing protection and a reduction in routing protocol (5).