Riverbed Optimization System (RiOS) 6.1

RiOS Technical Overview
appliance to a Steelhead appliance and is meaningful only to those appliances, so Correct Addressing sends that traffic using the
appliance addresses. . When performing Correct Addressing, RiOS also utilizes port 7800 for optimized traffic flows by default.
Using this dedicated port in Correct Addressing mode does not tunnel traffic over the WAN. Instead, the traffic remains unencapsulated
and TCP flows are proxied on a one-to-one basis for each connection.
Correct Addressing is the most commonly implemented visibility mode for Riverbed customers, because it is the easiest and most
reliable mode to deploy. Many organizations also use Correct Addressing in conjunction with real-time traffic such as VoIP,
videoconferencing, and other QoS traffic, and RiOS functions seamlessly in this mode. In addition, Steelhead appliances and
Virtual Steelhead, using Correct Addressing can perform NetFlow exports for customers who desire greater visibility as well. The
diagram below shows how traffic is essentially NATed as it traverses the infrastructure.
Figure-4: Correct Addressing mode uses Steelhead appliance addresses and ports over the WAN This is the default mode of operation and the vast majority of
implementations are deployed in this fashion.
Correct Addressing plus Port Transparency
Correct Addressing plus Port Transparency introduces a mild form of “spoofing” for the traffic sent over the WAN. Although the
appliances are actually sending optimized traffic that looks different to network inspection devices than the “original” un-optimized
traffic, Port Transparency uses those same original source and destination ports for optimized traffic sent across the WAN.
However, in this mode the WAN traffic is still addressed to and from the appliances’ IP addresses – only the port information is
spoofed. Customers using this mode keep the benefits of Correct Addressing in terms of reliability and ease of deployment, and
also gain the ability to solve some problems that are more easily addressed by spoofing ports. For example, integrating into some
port-based traffic classification or reporting systems on the WAN side of Steelhead appliances or Virtual Steelhead can be easier
by using Port Transparency.. Port Transparency still needs to be used with some caution since it can lead to unexpected results,
especially with any technologies that inspect traffic and check for anomalies; but it also has the significant benefit of avoiding the
more dangerous risks associated with spoofing source or destination IP addresses.
© 2010 Riverbed Technology. All rights reserved. 5