In a private network, N, that uses a NAT box, which of the following could enable an outside host x to make first contact with inside host y? A. x requests and receives y’s internal address from N's NAT box
B. x can bypass N's NAT box and send directly to the hardware address of y
C. y has a domain name that can be translated by an internal domain name server

Acomputer has a two-level cache. suppose that 60% of the memory references hit on the first level cache, 35% hit on the second level, and 5% miss. the access times are 5 nsec, 15 nsec, and 60 nsec, respectively, where the times for the level 2 cache and memory start counting at the moment it is known that they are needed (e.g., a level 2 cache access does not even start until the level 1 cache miss occurs). what is the average access time?