A. active/active firewall setup C8 [5 j9 q. y+ jB. single path in and out of the network. / ?& T% A: d7 j8 {0 T3 y( M RC. active/standby firewall setup 5 C0 ?. J0 }9 G. ?D. redundant routers running VRRP
国外论坛也在讨论这道题,给出的答案是D.$ S7 F( C& _4 c. W
Asymmetric routing is the scenario in which outing packet is through a path, returning packet is through another path. VRRP can cause asymmetric routing occur,9 R X# M" r" ^( P$ {; `; `, W
for example:! m j/ g7 w, Q4 T& Z8 M3 W
R1 and R2 are the two routers in the local internal LAN network that are running VRRP. R1 is the master router and R2 is the backup router.; @& s# V9 {$ m" M' D% P& j
These two routers are connected to an ISP gateway router, by using BGP. This topology provides two possible outgoing and incoming paths for the traffic. , p$ G. D9 Q* z7 \3 l2 {/ ISuppose the outgoing traffic is sent through R1 but VRRP failover occurs, R2 becomes the new master router -> traffic passing through R2 instead ->asymmetric routing occurs.