Note: To perform this task from PolicyCenter, you must first select a group and/or unit configuration from the Group: and Unit: drop-down lists at the top of the page.

Header Overhead (bytes)
Number of bytes that are added to each packet to account for WAN protocol header overhead

Link Overhead (ppt)
Number of parts per thousand* by which packet sizes are increased to account for link overhead. This adjustment is useful for links that do bit stuffing. (Bit stuffing is the practice of adding bits to a stream of data. Bit stuffing is required by many network and communications protocols, for example to prevent data from being interpreted as control information.)

* to be more precise, it’s actually parts per 1024

Small MSS Link Speed
Link speeds slower than this value will force the use of smaller MSS (maximum segment size)
Prevents PacketWise from changing the MSS on large WAN links

Maximum Segment Size (Inbound)
Maximum segment size of TCP packets on Inbound flows. This setting can help avoid packet fragmentation when using VPN and not being able to support 1500-byte packets (the default size) through the VPN tunnel.

Maximum Segment Size (Outbound)
Maximum segment size of TCP packets on Outbound flows

Clamp Early Retransmission (Inbound)
Number of milliseconds delay for clamping early retransmission time-out on Inbound packets. Puts a maximum on retransmit time.

Clamp Early Retransmission (Outbound)
Number of milliseconds delay for clamping early retransmission time-out on Outbound packets

Asymmetric Flows Only
By turning on this setting, PacketWise will automatically assume all flows are asymmetric and stop TCP Rate Control. In topologies where there are a large percentage of asymmetric flows, this may be more efficient than attempting to apply regular rate control. In addition to disabling rate control, turning on this setting disables all layer 7 classification activities. (PacketWise must see traffic in both directions in order to classify layer 7.)

Bridge PassThru
The Packeteer unit functions as a transparent bridge when traffic shaping is enabled — if the unit sees a packet with a source and destination MAC address on the same side, it will drop the packet since it doesn't need to be forwarded. In certain topologies, however, MAC addresses may be on the same side of the unit, but on different LANs. The packets will be dropped, but they shouldn't be. In this situation, you will want to enable bridge pass-through.

Caching of IP address-based classes
Cache IP address-based classes on the inside or outside of the Packeteer unit. Change this setting to outside to increase performance of classification if the majority of IP addresses in manually created classes are on the outside, rather than the inside.

Display "503 - Service unavailable" Messages
Control the display of the "503 - Service unavailable" server error message when a connection is refused because of admission control (such as a never-admit policy). When set to off, the "503 - Service unavailable" message will be customized with the text "This message is sent by Packeteer PacketShaper." When set to on, PacketWise will perform a TCP reset and drop the HTTP request; the error message will likely be "The attempt to load http://... failed."

Non-IP Flows
The number of new non-IP connections of a given type that must be identified within a one-minute time frame before PacketWise creates a class

Identifiable Services
The number of new connections of an identifiable service to a port less than or equal to 1024 that must be identified within a one-minute time frame before PacketWise creates a class

Dynamic Ports
The number of new connections of an identifiable service to a port greater than 1024 that must be identified within a one-minute time frame before PacketWise creates a class

Static Ports
The number of new connections to a static port within a one-minute time frame before PacketWise creates a Port_#### class in the DiscoveredPorts folder

It may be necessary to increase this value on Internet link deployments to prevent excessive number of DiscoveredPorts classes being created. If you don’t want any Port_#### classes discovered, set this variable to its maximum value.

Active
The number of seconds a dynamic partition will be retained after an established flow has sent packets

Note: If no other user needs a dynamic partition, the partition will be retained indefinitely.

Idle
The number of seconds a dynamic partition will be retained after an established flow has not sent or received packets

Note: If no other user needs a dynamic partition, the partition will be retained indefinitely.

Reserved for Static
The number of partitions reserved for static partitions; all other partitions can be used for dynamic or static partitions (applicable to Packeteer 1500 only)

Host Entries
The maximum number of hosts and partners that can be defined to use the compression facility

* 0 indicates that the default system limit will be used; the system limit depends on the amount of memory installed in the unit

ID Entries
The maximum number of entries (services, classes, and dictionaries) within a compression tunnel. For example, if HTTP is the first service to get compressed through a tunnel, two compression entries are created — one for the HTTP service and one for its shared group dictionary. If a second compressible service, such as ICMP, is detected and it uses the same group dictionary, only one compression entry is created (for the ICMP service).

* 0 indicates that the default system limit will be used; the system limit depends on the amount of memory installed in the unit.

Tunnels
The maximum number of compression tunnels

* 0 indicates that the default system limit will be used; the system limit depends on the amount of memory installed in the unit. For example, a Packeteer 8500 has a system limit of 100 tunnels.

Headers
Number of concurrent TCP flows per tunnel for header compression. By lowering this number, you can free up memory to create more compression tunnels. Raising this number from the default setting allows more flows to get header-compressed, but decreases the amount of memory available for tunnels.

* 0 indicates that the default system limit will be used; the system limit depends on the amount of memory installed in the unit.

Packing hold time
Maximum number of milliseconds packets will be held for packing. Packing is a feature of compression that combines multiple packets into a single "super packet," in order to save on overhead. Packing increases compression rates because less data is being sent out on the wire. When PacketShaper Xpress receives a packet, it is held up to the maximum packing hold time (10ms by default), waiting to be combined with additional packets. After that time expires, Xpress compresses all the accumulated packets into a super packet and sends it out.

A value of 0 disables packing.

Note: On very busy links, packing doesn't cause much latency because the packets are bundled and sent off quickly. On less active links, Xpress may have to wait to get enough packets in a bundle, possibly creating application performance problems. If you are experiencing latency, try lowering the packing hold time or disabling it altogether.

Packing ACK hold time
Maximum number of milliseconds to hold latency-sensitive packets, such as TCP ACKs, for packing.

Because packing adds latency, you can use this variable to adjust the maximum amount of time latency-sensitive packets will be held. By setting the value to 0, latency-sensitive packets will never wait for packing. If there are packets waiting to be packed, Xpress will pack the latency-sensitive packet with them and send out the compressed packet immediately; if there aren’t any packets waiting, the latency-sensitive packet will be sent without being packed.

Note: Increasing this setting and delaying ACKs too long can have severe negative performance implications on latency-sensitive applications like Netware and Citrix.

Transparent trigger threshold
The number of consecutive retransmissions of a packet before Xpress disables the compression tunnel and sends packets in the clear (uncompressed). The tunnel will resume normal operation after it gets an acknowledgment for the retransmitted packets; if acknowledgment is not received before the Tunnel shutdown threshold is reached, the tunnel will be shut down. (available in 6.0.1 and above)

Tunnel shutdown threshold
The maximum consecutive retransmissions of a packet before a compression tunnel is shut down (available in 6.0.1 and above)

Graph Timeout
The maximum number of seconds a graph can take to generate in the browser interface; if the graph takes longer to generate than this value, a system time-out error message will appear.

Note: Increasing this setting can make the browser interface appear to "freeze" while PacketWise is generating some of the more complex graphs. Sometimes the browser will not display the page until all of the graphs are generated.

Registered Events
The maximum number of events that can be registered

User-Defined Events
The maximum number of events that can be user-defined

Hot Standby Timeout
Number of milliseconds after which the standby unit becomes active if it has not received a keep-alive message from the active unit

Synthetic Transaction Timeout (Read)
Number of seconds after which a synthetic transaction will end when the response received is incomplete

Note: This variable is not available on PacketShaper ISP models.

Synthetic Transaction Timeout (Write)
Number of seconds after which a synthetic transaction will be canceled if the server fails to respond to a request

Note: This variable is not available on PacketShaper ISP models.

Maximum Frame Routes
The maximum number of route entries PacketWise can import from a FRAD or ATM routing table

Link State Mirroring
Enable/disable link state mirroring. With link state mirroring, PacketWise will bring down the second port of a NIC pair if the first goes down. This feature allows each Packeteer unit to sit between a WAN router and a switch without blocking detection of switch outages by the router. Link state mirroring is automatically enabled when direct standby is enabled and the redundant management port is connected.

Note: Link state mirroring is not active on the LEM being used for the direct link; this allows you to disconnect the redundant management port without impacting connectivity. However, link state mirroring is disabled when the redundant management link is disconnected.