tailieunhanh - Microsoft Press windows server 2008 tcp ip protocols and services phần 6

Các đo lường thích hợp của RTT và quyết tâm của RTO gửi phân đoạn TCP là quan trọng để ngăn chặn một hiện tượng của các mạng được định tuyến được gọi là sự sụp đổ tắc nghẽn. Tắc nghẽn sự sụp đổ xảy ra khi bộ đệm của bộ định tuyến liên mạng đầy năng lực và các bộ định tuyến bắt đầu loại bỏ các gói. | Chapter 11 Transmission Control Protocol TCP Connections In this chapter The TCP TCP Connection TCP Half-Open TCP Connection TCP Connection TCP Connection TCP Connection TCP is a connection-based protocol. Before data can flow on a TCP connection the connection must be formally established through a handshake process. To gracefully stop the flow of data on a TCP connection and release the resources of the connection it must be terminated through a similar handshake process. This chapter describes the details of TCP connection establishment and termination and the states of a TCP connection. The TCP Connection A TCP connection is a bidirectional full-duplex logical circuit between two processes Application Layer protocols in an IP internetwork. The TCP connection s endpoints are identified by an IP address TCP port pair. The connection is uniquely identified by both endpoints IP address 1 TCP port 1 IP address 2 TCP port 2 . TCP uses those four numbers to demultiplex the data portion of the TCP segment to the proper Application Layer process. A TCP connection can be visualized as a bidirectional data pipe containing two logical pipes between the two TCP peers as Figure 11-1 illustrates. One logical pipe is used for outbound data and the other logical pipe is used for inbound data relative to the TCP peer . The outbound data pipe for one TCP peer is the inbound data pipe for the other TCP peer. 223 224 Part III Transport Layer Protocols TCP HnOiitboiind j Inbound in TCP Peer z Peer 1 ụỵ Inbound iQutboundjf I 2 Figure 11-1 A TCP connection showing both inbound and outbound logical pipes TCP connections are Established through a handshake process in which both TCP peers agree to create a TCP connection. Optionally maintained through a periodic keepalive process that ensures that both TCP peers are active on the connection. Terminated through a handshake .