Comtech EF Data turboIP-G2 - Manual (Page 32)

turboIP-G2 Performance Enhancement Proxy Revision 2
Introduction CD-TURBOIP-G2
1–10
1.2.4.2 TCP/IP Performance Enhancement Proxy
Comtech EF Data’s turboIP-G2 Performance Enhancement Proxy is designed to alleviate TCP/IP
bottlenecks in an impaired environment (high delay, high bit error rate, or both), while preserving
interoperability with any TCP device. It achieves this by combining TCP with a number of
enhancements that modernize IP transport.
turboIP-G2 is based on SCPS-TP, the Transport Protocol of SCPS, an open standard specifically
defined for space communications. This standard is open, published, and internationally
distributed. SCPS-TP is an ISO standard (15893), a CCSDS standard (714.0-B-1), and a
MIL-STD (MIL-STD-2045-44000).
turboIP-G2 is fully compatible with network devices that use TCP, supporting existing Internet
standards, including network congestion and retransmission schemes. This allows turboIP-G2 at
one end of the link to operate with TCP devices at the other end of the link without the need for a
peer turboIP-G2 device, providing partial performance enhancement. However, it is
recommended that TCP traffic pass through a pair of turboIP
TM Performance Enhancement
Proxies, in order to take full advantage of the SCPS-TP protocol.
The key features of turboIP-G2 that help alleviate TCP/IP performance bottlenecks are:
• Quick Start. turboIP-G2 makes full and immediate use of the links available, eliminating
the inefficiencies of the TCP slow-start algorithm.
• Window Scaling. turboIP-G2 supports window sizes up to 1 GB, far exceeding the
standard TCP window size of 64 Kbytes.
• Intelligent Congestion Control. turboIP-G2 is optimized for real-world, mixed-loss
environments. It is capable of distinguishing data corruption from congestion-induced
data loss. Doing so prevents unnecessary activation of congestion control mechanisms,
which can lead to significant reductions in transmission rates.
• Selective Negative Acknowledgments (SNACKs). SNACKs identify specific lost or
damaged packets and request retransmission of those packets. This provides for quicker
recovery and better bandwidth utilization in lossy environments.
• Path MTU Discovery. turboIP-G2 allows Slipware to dynamically detect the allowed
MTU for the path between the Skip ware gateway and the peer gateway or end systems
for accelerated traffic, thus eliminating fragmentation of TCP segments that are too large
for the path MTU.
• Tolerance for packet reordering. turboIP-G2 prevents spurious retransmissions due to
packet reordering in the path between two skip ware gateways
• Support for large queues with congestion control. turboIP-G2 prevents spurious
retransmissions timeouts (RTO) caused by an increase in RTT due to queuing, improving
throughput when using the Per-Connection congestion control on long delay networks
that support large queues.