Look at K TCP connections, each with a different end-to-end path, but all passing through a bottleneck link with transmission rate R bps. (By bottleneck link, we mean that for each connection, all the other links along the connection's path are not congested and have abundant
In this section we return to our study of TCP. As we learned in Connection-Oriented Transport TCP, TCP provides a reliable transport service between two processes running on different hosts. Another key component of TCP is its congestion-control mechanism. As indicated
We close this section with a brief case study of the congestion-control algorithm in ATM ABR - a protocol that takes a network-assisted approach toward congestion control. We emphasize that our objective here is not to describe aspects of the ATM architecture in great detail,
In TCP Congestion Control, we'll look at TCP's specific approach to congestion control in great detail. Here, we identify the two broad approaches to congestion control that are taken in practice and discuss particular network architectures and congestion-control protocols
In the previous sections, we considered both the general principles and specific TCP mechanisms used to provide for a reliable data transfer service in the face of packet loss. We mentioned earlier that, in practice, such loss usually results from the overflowing of router buffers as
In this section well examine how a TCP connection is established and torn down. Though this topic may not seem particularly exciting, it is important because TCP connection establishment can considerably add to perceived delays (for instance, when surfing the Web). Moreover,
Remember that the hosts on each side of a TCP connection set aside a receive buffer for the connection. When the TCP connection receives bytes that are correct and in sequence, it places the data in the receive buffer. The associated application process will read data from this
Remember that the Internet's network-layer service (IP service) is untrustworthy. IP does not guarantee datagram delivery, does not guarantee in-order delivery of datagrams, and does not guarantee the integrity of the data in the datagrams. With IP service, datagrams can
TCP, like our rdt protocol in Principles of Reliable Data Transfer, uses a timeout/retransmit mechanism to recover from lost segments. Though this is conceptually simple, many subtle issues arise when we implement a timeout/retransmit mechanism in an actual protocol such
Having briefly examined the TCP connection, let's look at the TCP segment structure. The TCP segment comprises header fields and a data field. The data field includes a chunk of application data. As mentioned above, the MSS limits the maximum size of a segments data field.