The wireless network is provided by numerous Cisco APs (signal propagation in a steel ship at sea is terrible). The wired network is run by a series of Cisco 2900 gigabit switches. Both VLANs have wired and wireless clients. Both VLANs are piped into a SonicWall TZ 215 (running SonicOS Enhanced 5.8.1.2-6o) which controls the pipe to the Internet. The network consists of two VLANs (one for ship's computers, and the other for guests). At the moment, we have about 300 people aboard, all sharing that pipe. Being a satellite link, it runs about 650ms ping times. Unfortunately, the bandwidth costs for this type of link are prodigious, so we're stuck with a 1Mbps down / 512kbps up connection. It uses a satellite link to communicate with the Internet. The network in question is aboard a ship at sea. Let me lay out our situation, and I would love to hear from people more knowledgeable than myself on other directions of inquiry to resolve the problem. What's confusing me is that as far as I know, there are only two reasons for this sort of issue: a flaky link that drops packets, and congestion. 36 samples (taken with Wireshark 1.10.8 running on 32-bit Windows 7) totaling a little over seven hours, ranging between 2 and 53 minutes each shows retransmits occupying between 43 and 61 percent of the total ingress bandwidth. I've been attempting to troubleshoot a network issue that presents with very high rate of TCP retransmits.
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