Please refer to WAAS sizing guidelines to size specific to customer requirements. * NME Hardware Assist for Enterprise Class Virtual. Blades . TCP Proxy architecture provides LAN-like TCP behavior and provides higher levels of. Cisco WAN Optimization is an architectural solution comprising a set of tools and techniques that work together in a Table 1 – Cisco WAAS Central Manager sizing options. Device .. of the chosen hardware form-factor. All connections are . Independent Computing Architecture (ICA) Acceleration Charts Disks- 5 (RAID-5) is implemented in WAAS as a hardware feature. RAID-5 devices can . Complete the sizing phase that includes the following tasks.
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Cisco WAAS is a software component that hafdware resident on a hardware device deployed at each location with users and servers. The distinction between the two is that a WAVE device, available only as an appliance, can also provide branch office virtualization services in conjunction with WAN optimization and application acceleration.
WAE devices provide only WAN optimization wass application acceleration and do not provide virtualization. This chapter provides an introduction to the Cisco WAAS hardware family, along with an in-depth examination of the hardware and software architecture.
This chapter also looks haddware the licensing options for Cisco WAAS, positioning for each of the hardware platforms, and performance and scalability metrics for each of the platforms. The Cisco WAAS product family consists of a series of appliances and router-integrated network modules that are based on an Intel x86 hardware architecture.
The product family scales from MB of memory to 24 GB archigecture memory, utilizing single-processor subsystems up to dual quad-core processor subsystems. Each Cisco WAAS device, regardless of form factor, is configured with some amount of hard disk storage and a compact flash card.
The compact flash card is used for boot-time cusco and configuration files, whereas the hard disk storage is used for optimization data including object cache and Data Redundancy Elimination [DRE] sizijg, swap space, software image storage repository, and guest operating system storage in the case of WAVE devices.
Having a compact flash card enables the device to remain accessible on the network should the device suffer hard drive subsystem failure for troubleshooting and diagnostics purposes in such a scenario, optimization and virtualization services would not be operational.
Hardware Family > Cisco WAAS Architecture, Hardware, and Sizing
Also, by using the compact flash card in this way, a WAAS device can successfully boot and become accessible on the network if no disks are available to the device. The Cisco Linux platform is cisoc to ensure that rogue services are not installed and secured such that third-party software or other changes cannot be made. The Cisco Linux platform hosts a command-line harvware CLI shell similar to that of Cisco IOS Software, which, along with the Central Manager and other interfaces, form the primary means of configuring, managing, and troubleshooting a device or system.
All relevant configuration, management, monitoring, and troubleshooting subsystems are made accessible directly through this CLI as opposed to exposing the Linux shell. These include disk encryption, Central Management Subsystem CMSinterface manager, reporting facilities, network interception and bypass, application traffic policy ATP engine, and kernel-integrated virtualization services, as shown in Figure Cisco WAAS devices can be configured to encrypt the data, swap, and spool partitions on the hard disk drives using encryption keys that are stored on and retrieved from the Central Manager.
The disk encryption feature uses AES encryption, the strongest commercially available encryption, and keys are stored only in the WAAS device memory after they have been retrieved from the Central Manager during the device boot process. Should a WAAS device be physically compromised or a disk stolen, power is removed from the device, which destroys the copy of the key in memory memory is not persistent.
When the hard disks are encrypted, loss of the key renders data on the disk unusable and scrambled. Keys are stored in the Central Manager database which can be encrypted and synchronized among all Central Manager devices for high availability. If a WAAS device is not able to retrieve its key from the Central Manager during boot time, it remains in pass-through mode until connectivity is restored or disk encryption is administratively bypassed. Each WAAS device includes two integrated Gigabit Ethernet interfaces including the network modules, one interface is internal and shares connectivity to a peer interface in the router through the router backplane, the other is external and can be cabled to a LAN switch, similar to an appliance.
Each WAAS appliance has expansion slots to support one or more additional feature cards, such as the inline bypass adapter, which has two two-port fail-to-wire pairs. The interface manager also provides management over logical interfaces that can be configured over physical interfaces.
Cisco WAAS Architecture, Hardware, and Sizing
Another logical interface is the PortChannel interface, which can be used to team WAAS device interfaces together for the purposes of high availability and load balancing. Cisco Linux provides an interface for the Cisco WAAS software to use for purposes of monitoring and generating alarms. Cisco WAAS also supports the definition of up to four syslog servers, which can be used as amd recipients when syslog messages are generated.
Transaction logs are not covered in this book, but a full reference on their usage can be found in the Cisco WAAS documentation.
The alarm book which covers syslog messages, SNMP traps, and Central Manager dashboard alarmserror book which covers console messagesand product documentation can be downloaded from Cisco. The network interception and bypass manager is used by the Cisco WAAS device to establish relationships with intercepting devices where necessary and ensure low-latency bypass of traffic that the WAAS device is not intended to handle.
As flows are intercepted by the WAAS device and determined to be candidates for optimization, those flows are handed to the Application Traffic Policy ATP engine to identify what level of optimization and acceleration should be applied based on the configured policies and classifier matches.
The ATP is discussed in the next section, and Chapter 8 and Chapter 9 discuss the configuration and management of policies. The ATP is responsible for examining details of each incoming flow after being handled by the interception and bypass mechanisms in an attempt to identify the application or protocol associated with the flow. This association is done by comparing the packet headers from each flow against a set of predefined, administratively configured, or dynamic classifiers, each with its own set of one or more match conditions.
Flows that do not have a match with an existing classifier are considered “other” traffic and are handled according to the policy defined for other traffic, which indicates that there are no classifier matches and that the default policy should be used.
When a classifier match is found, the ATP examines the policy configuration for that classifier to determine how to optimize the flow. The ATP also notes the application group to which the classifier belongs to route statistics gathered to the appropriate application group for proper charting visualization and reporting. The configured policy dictates which optimization and acceleration components are enacted upon the flow and how the packets within the flow are handled.
The list of configurable elements within a policy include the following:. Settings configured in the policy are employed in conjunction with one another. This can be coupled with a configuration that applies a specific DSCP marking to the packets within the flow.
This is defined in a single policy, thereby simplifying overall system policy management. The ATP is consulted only during the establishment of a new connection, which is identified through the presence of the TCP synchronize SYN flag which occurs within the first packet of the connection.
By making a comparison against the ATP using the SYN packet of the connection being established, the ATP does not need to be consulted for traffic flowing in the reverse direction, as the context of the wxas is established by all WAAS devices in the path between the two endpoints and applied to all future packets associated with that particular flow.
Figure shows how the ATP engine interacts with a flow and a particular policy. As of version 4.
The WAAS VB architecture helps enable customers cixco further consolidate infrastructure by minimizing the number of physical servers required in the branch office for those applications which are not good candidates for centralization into a data center location.
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Sample Chapter is provided courtesy of Cisco Press. Chapter Description This chapter provides an introduction to the Cisco WAAS hardware family, along with an in-depth examination of the hardware and software architecture. It also looks at the licensing options for Cisco WAAS, positioning for each of the hardware platforms, and adn and scalability metrics for each of the platforms. Hardware Family Next Section. About Affiliates Cisco Systems, Inc.