Understanding the behavior of TCP for real-time CBR workloads

ABSTRACT

In this paper, we examine the feasibility of sending real-time CBR workloads over TCP. This is motivated by the friendliness of NATs and firewalls towards TCP as opposed to UDP as well as by recent improvements in Internet's bandwidth and loss rates. Traditionally, TCP has been considered undesirable for real-time CBR workloads. We evaluate this assertion by developing a novel analytical tool that yields TCP's sender-to-receiver socket delay distribution for CBR workloads. A key insight gained is that the use of smaller than MSS-sized packets in CBR workloads can exploit the TCP's ACK counting mechanism thereby limiting the delay impact of congestion window variations. We leverage this insight to provide a heuristic and system-level guidelines for reducing TCP transport delays.

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