Riverbed SteelHead 5080, Руководство по установке и настройке

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22 | Product Overview
Fail-to-block (disconnect) mode
When the SteelHead is in bypass mode the traffic passes through uninterrupted. Traffic that was
optimized might be interrupted, depending on the behavior of the application-layer protocols. When
connections are restored, they succeed, although without optimization.
In an out-of-path deployment, if the server-side SteelHead fails, the first connection from the client fails.
After detecting that the SteelHead is not functioning, a ping channel is setup from the client-side
SteelHead to the server-side SteelHead. Subsequent connections are passed through unoptimized.
When the ping succeeds, processing is restored and subsequent connections are intercepted and
optimized.
For detailed information about the ping command, see the Riverbed Command-Line Interface
Reference Manual .
Fail-to-block (disconnect) mode
In fail-to-block mode, if the SteelHead has an internal software failure or power loss, the SteelHead LAN
and WAN interfaces power down and stop bridging traffic.
When fail-to-block mode is enabled, a failed SteelHead blocks traffic along its path, forcing traffic to be
rerouted onto other paths (where the remaining SteelHeads are deployed). This is only useful if the
network has a routing or switching infrastructure that can automatically divert traffic off of the link once
the failed SteelHead blocks it.
Note: You can use this mode with connection-forwarding, the allow-failure CLI command, and an additional
SteelHead on another path to the WAN to achieve redundancy. For more information, see the Riverbed Command-
Line Interface Reference Manual .
You set fail-to-block mode in the SteelHead CLI. For detailed information, see the SteelHead
Deployment Guide .
Upgrading RiOS
This section provides information specific to upgrading and downgrading the SteelHead. For more
general information and procedures, see
Chapter 1, “Riverbed Software Licenses, Upgrades, and Image
Signing.”
RiOS is backward compatible with previous RiOS versions. However, to obtain the full benefits of the new
features in the software, you must upgrade the client-side and server-side SteelHeads on any given WAN
link. After you have upgraded all linked appliances, all the benefits of the features and enhancements are
available.
The SteelHead uses image signing verification to ensure that software upgrades and downgrades are
authentic Riverbed images.