《计算机网络(第四ç‰?》习题答æ¡?- 百度文库 ÏÂÔر¾ÎÄ

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IDLE¡ª Connection not established yet.

WAITING¡ª CONNECT has been executed and CALL REQUEST sent. QUEUED¡ª A CALL REQUEST has arrived; no LISTEN yet. ESTABLISHED¡ª The connection has been established.

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SENDING¡ª The user is waiting for permission to send a packet. RECEIVING¡ª A RECEIVE has been done.

DISCONNECTING¡ª A DISCONNECT has been done locally.

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6-10 Out of curiosity, the implementer of the transport entity of Fig. 6-20 has decided to put counters inside the sleep procedure to collect statistics about the conn array. Among these are the number of connections in each of the seven possible states, ni (i = 1, ... ,7). After writing a massive FORTRAN program to analyze the data, our implementer discovers that the relation Sni = MAX_CONN appears to always be true. Are there any other invariants involving only these seven variables?

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6-11 What happens when the user of the transport entity given in Fig. 6-20 sends a zero-length message? Discuss the significance of your answer.

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