Comtech EF Data turboIP v4.0 - Manual (Page 16)

turboIPv4.0 Revision 6
Overview MN/TURBOIP.IOM
The key features of turboIP™ that help alleviate TCP/IP performance bottlenecks are:
Quick Start turboIP™ makes full and immediate use of the links available, eliminating
the inefficiencies of the TCP slow-start algorithm.
Window Scaling turboIP™ supports window sizes up to 1 Gbyte, far exceeding the standard
TCP window size of 64 Kbytes.
Intelligent
Congestion
Control turboIP™ 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.
Rate Pacing
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turboIP™ meters out bursty traffic at a rate not to exceed the configured
transmission rate of the satellite channel. This prevents the satellite channel
from becoming congested.
Per-Connection
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turboIP™ Version 4.0 adds Per-Connection Mode to support dynamic
bandwidth paths, where the bandwidth may be different for any of the paths
being accelerated by the turboIP.
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.
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Note: With turboIP™ Version 4.0, either Rate Pacing or Pre-Connection Mode can be
selected to optimize TCP acceleration performance.
Rate Pacing Mode Should be used when the bandwidth path for accelerated TCP
traffic remains constant with the set WAN Transmission Rate.
Per-Connection Mode Should be used to support dynamic bandwidth paths, where the
bandwidth may be different for any of the paths being accelerated
by the turboIP.
1.4 S
ELECTIVE
A
CCELERATION
Selective Acceleration implemented by the Comtech turboIP is a mechanism for providing
different quality of service (QoS) for different datagrams. Selective Acceleration only applies to
IPv4 datagrams that are received on the LAN interface and forwarded to the WAN interface.
Selective Acceleration is implemented as an ordered table of rules that determine the QoS to be
provided for traffic passing through the turboIP. The rules have three parts: an accounting part
that specifies the location and status of the rule in the table, a filter part that matches the
datagram’s passing through the turboIP to each rule, and a QoS part that determines how the data
that matches the rule is to be treated. Each rule can specify that either all packets matching the
rule be dropped or the following QoS parameters be applied:
• A priority level
• A maximum data rate (bandwidth) for all traffic matching the rule
•
Whether or not to accelerate TCP sessions matching the rule (i.e., invoke
SCPS-TP)
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