auto | Specifies the automatic detection of TCP optimization. This mode detects the optimal TCP optimization by using the peer SteelHead appliance mode for inner connections, SkipWare when negotiated, or standard TCP for all other cases. Both the client-side and the server-side SteelHead appliances must be running RiOS 7.0. For single-ended interception connections, this mode uses SkipWare when possible, or standard TCP otherwise. |
default | Specifies standard TCP optimization (RFC compliant). This mode optimizes non-SCPS TCP connections by applying data and transport streamlining for TCP traffic over the WAN. For details on data and transport streamlining, see the SteelHead Deployment Guide. This option clears any advanced bandwidth congestion control that was previously set. |
hstcp | Specifies high-speed TCP optimization. This option allows for more complete use of long fat pipes (high-bandwidth, high-delay networks). Do not enable for satellite networks. We recommend that you enable high-speed TCP optimization only after you have carefully evaluated whether it benefits your network environment. |
bw-est | Specifies TCP bandwidth estimation optimization. This option calculates optimal transmission window sizes. Satellite networks typically have high latencies (order of 600ms to 1.2s), variable bandwidth, and packet losses (in chunks). |
per-conn-tcp | Specifies SkipWare per-connection TCP optimization. Applies TCP congestion control to each SCPS-capable connection. The congestion control uses: • a pipe algorithm that gates when a packet should be sent after receipt of an ACK. • the NewReno algorithm, which includes the sender's congestion window, slow start, and congestion avoidance. • timestamps, window scaling, appropriate byte counting, and loss detection. |
err-tol-tcp | Specifies SkipWare error-tolerant TCP optimization. Enables SkipWare optimization with the error rate detection and recovery mechanism on the SteelHead. This option allows the per-connection congestion control to tolerate some amount of loss due to corrupted packets (bit errors), without reducing the throughput. Use caution when enabling error-tolerant TCP optimization, particularly in channels with coexisting TCP traffic, because it can adversely affect channel congestion with competing TCP flows. |
cubic | Enables the cubic congestion-control algorithm for optimizing TCP. Enabling cubic mode accelerates .traffic over the internet for SaaS services. When two SteelHeads peer with each other, they exchange their congestion control (CC) algorithm (among other things) on an out-of-band channel. If a SteelHead is configured to autonegotiate, it uses the same algorithm as the peer SteelHead. If both use autonegotiate, they fallback to a local default, which in RiOS 9.10 or later is the cubic congestion control algorithm. Prior versions of RiOS default to New Reno TCP. |