Riverbed SteelHead 5080, Руководство по установке и настройке

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Product Overview | 19
Overview of the SteelHead
Application streamlining
In addition to data and transport streamlining optimizations, RiOS supports a rich set of application
protocols that includes but is not limited to Microsoft Exchange, CIFS, SMB, SharePoint, HTTP/HTTPS,
Lotus Notes, FCIP, SRDF, and SnapMirror.
Path selection for hybrid networking
These solutions maximize multiple WAN services based on business needs, service quality, and costs.
Path selection redirects specific traffic or applications through one of three alternate paths determined
by destination availability in cascading order. The path selection technology deterministically redirects
select traffic and application flows through alternate networks based on service metrics, such as path
availability, application priority, and policies you create.
Traffic classification
The SteelHead application flow engine, which covers more than 1,300 individual applications and
processes, uses information to understand where data is coming from, which application sent it, and
what function that application is trying to accomplish. The application flow engine utilizes a variety of
techniques, often in combination, such as port-based classification, application signature matching,
protocol dissection, behavioral classification, and others. Path selection classifies traffic using the full
assortment of packet rules including IP addresses, 5-tuple, differentiated services code point (DSCP),
TCP, user datagram protocol (UDP) port numbers, and so on. In this way, operators can instruct
SteelHead solutions to precisely associate applications to networks based on their nature, performance
requirements, and business criticality.
Packet forwarding
After the SteelHead has selected the right path, the next step is for it to steer traffic to the newly selected
path. This operation is transparent to the client, server, and any networking devices such as routers or
switches. RiOS forwards packets either directly using distinct SteelHead physical interfaces, or indirectly
using (MAC) address rewriting. When these forwarding methods aren’t possible. For example, with virtual
in-path deployments or where the SteelHead solution is not in the same Layer-2 domain, RiOS uses
DSCP marking with upstream policy-based routing.
Availability monitoring
The SteelHead monitors end-to-end path availability and quality. You define the endpoint IP address for
every path, and the SteelHead sends an Internet Control Message Protocol (ICMP) ping every two
seconds. To validate availability, each path can have a different remote host.
Failover management
If three consecutive pings are missed, the system considers the path to be unavailable, and selects the
backup path. Every application has a default and a prioritized set of backup paths. Should the default path
be unavailable, the higher-priority backup is instantly used (and then the lower one if needed). Operators
can block certain types of applications when the primary path becomes unavailable, with a goal of
reserving the remaining available bandwidth for more critical applications. As soon as the default path
becomes available, traffic is routed back to it.
Management streamlining