Watch Mode Overview
Packeteer's watch mode is used when you don’t want the Packeteer unit to be cabled into the main data path — when your situation requires that the unit monitor the traffic non-inline. This type of deployment is sometimes required for data centers that have restrictions on the introduction of inline elements into the network.
This feature works with PacketSeeker, PacketShaper, PacketShaper ISP, and PacketShaper Xpress units. When a unit is in watch mode, it passively monitors the traffic on your network and performs all the traffic classification and reporting tasks that PacketShapers and PacketSeekers typically do: identify your network traffic, measure response times, track bandwidth utilization, notify you of conditions of interest, and report on the performance of your applications and network. It can provide you with insight into what applications are being used on your network and highlight performance issues. Consistent with its role as a passive watcher, a Packeteer unit in watch mode will not perform traffic shaping; any existing policies and partitions will be ignored.
Note: Because a Packeteer unit in watch mode cannot perform traffic shaping, this feature is more often used on PacketSeekers, rather than PacketShapers. The watch mode documentation refers to using watch mode on PacketSeekers, but bear in mind that it works on PacketShapers as well.
In watch mode, PacketSeeker’s OUTSIDE port(s) are used for monitoring network traffic and the INSIDE port(s) can be used for managing the unit itself. PacketWise decides which port to use for management access by looking at which INSIDE ports are connected. If none of the INSIDE ports is connected, the OUTSIDE port can be used for management. If more than one INSIDE port is connected, only one will be active and pass traffic; the other connected ports will provide redundant management access, in case of link failure. To see which port is configured for management access, view the Watch Mode Configuration page. (See Display Watch Mode Configuration for more information.)
Watch mode is supported in a variety of network configurations. One example is shown above; see the Getting Started Guide for other supported topologies.
PacketSeeker in watch mode includes the following features:
Is compatible with SPAN ports, mirrored switch ports, and hubs connecting multiple routers
Can monitor traffic to/from up to 256 WAN routers
Can receive traffic from up to three network segments (if LAN Expansion Modules are installed)
Can be managed from a separate network than the one being monitored
Non-Inline Deployment Requirements and Limitations
Packeteer's non-inline deployment has the following requirements and limitations:
Packeteer has tested and certified watch mode compatibility with the Cisco Catalyst 4000/5000 series and the Dell PowerConnect 5212.
Packeteer has tested and certified tap compatibility with the following NetOptics taps: 10/100 Ethernet, Gigabit 1000BaseTX, and fiber-optic splitter.
Packeteer's watch mode and direct standby features cannot be used together.
The host show command will not display output if both of the main LEM ports are disconnected and watch mode is enabled.
Compression Estimator Mode
Another useful application of the watch mode feature is to evaluate Packeteer’s Xpress compression feature, using a single Packeteer unit. When a Packeteer unit is deployed non-inline with compression and watch mode enabled, PacketWise will estimate the amount of compression that would have occurred on outbound data if the unit had been deployed inline. All the compression statistics, graphs, and reports are accessible and reflect an estimation of compression benefits. To come up with these estimates, Xpress does not compress the live data; it compresses the packets in the outbound direction (those that are destined to routers on the router watch list) and then drops the compressed data.
Packeteer's Compression Estimator capability provides you with a simple way to project compression gains from PacketShaper's Xpress option with a single unit evaluation. Deployed using mirrored switch ports, taps, or SPAN ports, Compression Estimator allows PacketSeeker to monitor traffic and estimate the bytes saved for different application traffic types and produce overall compression savings estimation for the entire link.
See Configure Compression Estimator.
Compression Estimator Limitations
Compression Estimator mode has the following limitations:
Works on outbound traffic only. An outbound data center traffic installation represents a good proxy for traffic mixes. Due to the asymmetric nature of traffic, the majority of traffic is served outbound from data center servers and represents a suitable proxy for overall network traffic.
Offers statistics on byte savings and bandwidth increases, but doesn't provide differences in response times. (An inline deployment of PacketShaper Xpress offers this capability.)
Is not applicable where existing PacketSeekers or PacketShapers are deployed inline. This mode is targeted for new customers. Existing customers with inline deployments can enable compression evaluation keys on two PacketShapers to enable a real-world test. |
發表於 2008-5-7 11:57
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