IxChariot is commercial enterprise-level network assessment tool that can simulate real-world network environments and applications at the transport layer (Layer 4), supporting testing via TCP, UDP, RTP, IPX, SPX, IPv4, IPv6, IP Multicast, and VoIP. You can measure throughput, jitter, packet loss, end-to-end delay, MOS and MDI. It's offered as a Windows-based console but also provides endpoint software for many platforms, including Windows CE, Linux, Sun Solaris, Novell Netware, and others.

Find out more about IXChariot over at ixia here or checkout a list of comprehensive tools over at LinkedIn here.