Refer to the exhibit. Which switching feature is being tested?()
A.loop guard
B.PortFast
C.root guard
D.BDPU guard
R1(AS1)------R2(AS2)-----R3(AS2)----R4(AS2) ,R1在AS1,R2,R3,R4在AS2,R1和R2建EBGP , R2和R3 IBGP,R3和R4 IBGP,產(chǎn)生BGP路由從R1傳給R2,問這條路有會(huì)不會(huì)在R4上出現(xiàn),如果不會(huì),怎么解決.