Riverbed SteelHead 5080, Руководство по установке и настройке

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Product Overview | 21
Fail-to-wire (bypass) mode
• Pass-through - Allow the SYN packet to pass through the SteelHead. No optimization is performed
on the TCP connection initiated by this SYN packet.
• Discard - Drop the SYN packet silently.
• Deny - Drop the SYN packet and send a message back to its source.
Peering rules
Peering rules determine how a SteelHead reacts when it sees a probe query. Peering rules are an ordered
list of fields a SteelHead uses to match with incoming SYN packet fields: for example, source or
destination subnet, IP address, VLAN, or TCP port, as well as the IP address of the probing SteelHead.
This is especially useful in complex networks. These types of peering rules are available:
• Auto - If the receiving SteelHead is not using enhanced autodiscovery, this has the same effect as
the Accept peering rule action. If enhanced autodiscovery is enabled, the SteelHead only becomes
the optimization peer if it’s the last SteelHead in the path to the server.
• Accept - The receiving SteelHead responds to the probing SteelHead and becomes the remote-
side SteelHead (that is, the peer SteelHead) for the optimized connection.
• Passthrough - The receiving SteelHead doesn’t respond to the probing SteelHead, and allows the
SYN+ probe packet to continue through the network.
For detailed information about in-path and peering rules and how to configure them, see the SteelHead
User Guide .
Fail-to-wire (bypass) mode
All SteelHead models and in-path network interface cards support a fail-to-wire mode. In the event of a
failure or loss of power, the SteelHead goes into bypass mode and the traffic passes through
uninterrupted.
Many in-path network interface cards (NICs) also support a fail-to-block mode in which case if there’s
a failure or loss of power, the SteelHead LAN and WAN interfaces power down and stop bridging traffic.
The default failure mode is fail-to-wire mode.
If there’s a serious problem with the SteelHead or it’s not powered on, it goes into bypass mode to
prevent a single point of failure. If the SteelHead is in bypass mode, you are notified in these ways:
• The Intercept/Bypass status light on the bypass card is triggered. For detailed information about
bypass card status lights, see the appendixes that follow.
• The Dashboard of the Management Console displays the Critical health icon next to the appliance
name.
• SNMP traps are sent (if you have set this option).
• The event is logged to system logs (syslog).
• Email notifications are sent (if you have set this option).
When the fault is corrected, new connections receive optimization; however, connections made during
the fault aren’t optimized. To force all connections to be optimized, enable the
kickoff feature. Generally,
connections are short-lived and kickoff is not necessary. For detailed information about enabling the
kickoff feature, see the
SteelHead User Guide and the SteelHead Deployment Guide .