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First Steps to Using Xpress Compression and Acceleration

Table of Contents

Overview ...............................................................................................................................................................................................1 Compression .................................................................................................................................................................................1 Packet Packing .............................................................................................................................................................................1 Acceleration ..................................................................................................................................................................................2 Xpress Modes................................................................................................................................................................................2 Requirements and Limitations ...............................................................................................................................................2 Migrating to Xpress 8.x ....................................................................................................................................................................3 Migration Mode ...........................................................................................................................................................................3 Migration Procedure ..................................................................................................................................................................3 Step 1: Upgrade One Site to PacketWise v8.x ...................................................................................................................4 Step 2: Verify Legacy Compression.......................................................................................................................................4 Step 3: Set Enhanced Tunnel Options .................................................................................................................................5 Step 4: Upgrade a Partner Unit...............................................................................................................................................6 Step 5: Set Tunnel Passwords .................................................................................................................................................6 Step 6: Test Enhanced Tunnels...............................................................................................................................................6 Step 7: Upgrade All Units to PacketWise v8.x ...................................................................................................................8 Step 8: Switch to Enhanced Tunnel Mode .........................................................................................................................8 Using Enhanced Tunnel Mode ................................................................................................................................................... 10 Defining Xpress-IP Addresses .............................................................................................................................................. 10 Enabling/Disabling Tunnel Features................................................................................................................................. 11 Setting Global Tunnel Options............................................................................................................................................ 12 Monitoring Tunnels................................................................................................................................................................. 13 Viewing the Compression Summary................................................................................................................................. 14 Displaying the Acceleration Summary ............................................................................................................................. 17 Compression Problems? ........................................................................................................................................................ 17 Acceleration Problems? ......................................................................................................................................................... 19

Table of Contents

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First Steps to Using Xpress

Overview

Packeteer's Xpress feature allows you to use compression to increase the virtual size of WAN bandwidth, use acceleration to fully utilize bandwidth in moderate to high latency environments, and use compression and/or acceleration to improve application performance on your network. By integrating these technologies with traffic management, PacketWise ensures that the increased virtual WAN pipe is not consumed by aggressive, nonmission critical applications that burst to consume any bandwidth given to them. In addition, the effective throughput of the mission critical traffic can also increase, providing a double benefit. Traffic management protects mission critical traffic, contains recreational and unsanctioned traffic, and smooths peaks in bursty traffic, while Xpress provides greater throughput and network capacity. Xpress works by identifying other PacketShapers on the network, dynamically setting up a communication link, called a tunnel, between the units, and sending data through the tunnels. Xpress uses tunnels to transport compressed data, packed data, and/or accelerated data. Each of these features is described in the following sections. Note: Compression and packing are features included with the compression key. Acceleration requires the acceleration key.

Compression

Xpress compression shrinks the size of transferred traffic, effectively increasing the amount of bandwidth available on a link. It uses a variety of methods, called compression algorithms, to compress data, for example ICNA, CNA, PRED1, PRED2, and RETD. You can enable/disable compression globally, for a specific tunnel, or on a perclass or perservice basis. Xpress does not attempt to compress all traffic. Because PacketShaper is application intelligent, it is able to identify each traffic flow and compress only the flows that are likely to achieve useful gains. Previously compressed traffic (such as streaming media) and encrypted data (such as HTTPS) are examples of non compressible traffic. The ability to apply appropriate compression algorithms to different applications is built into the Xpress compression engine. Xpress automatically assigns the appropriate algorithm to each application, in order to achieve the best compression ratio, with minimal latency.

Packet Packing

When Xpress packing is enabled, multiple packets are combined into a single "super packet" before being sent through the Xpress tunnel. Since fewer packets are sent, packing saves on overhead introduced by packet headers. You can enable/disable packet packing globally, for a specific tunnel, or on a perclass or perservice basis. Packing is a feature that is included with the compression key. The maximum size of the super packet is determined by the Maximum Transfer Unit, or MTU. MTU is the largest datagram than can be transmitted by an IP interface, without it needing to be broken down into smaller units. Because the packet size is maximized to the MTU, packing improves link utilization. The MTU can be set globally or for an individual tunnel. Since different types of traffic can tolerate different amounts of latency, each service is assigned an appropriate packing hold time -- the length of time the super packet is held to wait for additional packets to be packed into it. For example, latencysensitive services, such as RadioNetscape and Streamworks, have a preset 1ms packing hold time. The default packing settings are appropriate in most situations, but CLI commands are available to finetune these settings if you find the need. Due to the inherent delay in the process of combining packets, packing will increase network latency. 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 wait time or disabling packing altogether.

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Packing is most efficient and effective when dealing with small packets or packets that can be reduced in size with compression.

Acceleration

The acceleration feature significantly improves the performance of TCP/IP over satellite links or longdelay terrestrial networks. It accelerates both transactions and file transfers to enhance network performance. Xpress acceleration allows you to maximize bandwidth utilization, speed up application response times, accelerate the transfer of large files, and minimize the impact of other problems that are common with TCP based applications on highlatency links. A highlatency environment is generally any link with ping time of 150 ms or more. Virtually all overseas connections and the majority of East Coast West Coast US links are high latency. The benefits of acceleration are not restricted to networks with high latency -- other factors come into play as well. Highspeed links with small window sizes and moderate latency can also benefit from Xpress acceleration. For example, a data center with a 45 Mbps link, using Windows 2000 with a 16K window size, has a 30 ms roundtrip time during data backups. Because of the small window size, the link is underutilized and is less than 10 percent full. With Xpress acceleration, the data center would be able to fully utilize the bandwidth in the 45 Mbps link. You can enable/disable acceleration globally, for a specific tunnel, or on a perclass or perservice basis. In addition to accelerating data between PacketShapers, Xpress can accelerate data between a PacketShaper and a SkyX device. This is called a SkyX tunnel.

Xpress Modes

To help in the transition to the new capabilities in Xpress, three modes are offered: enhanced, legacy, and migration. · Legacy mode uses the PacketWise v6.x/7.x tunnel infrastructure. In legacy mode, the commands and capabilities are limited to those that were available in PacketWise 7.x. A tunnel's sole capability is to transport compressed data. · Enhanced mode uses the new 8.x tunnel infrastructure. In enhanced mode, a tunnel serves multiple purposes and can include one or more of the following: compression, packing, and acceleration. Al though the basic functionality of compression is the same in legacy and enhanced modes, enhanced compression is more efficient, has better firewall and MPLS support, and is more tolerant to latency and loss. Instead of the IPCOMP protocol used in legacy compression, enhanced mode transports compressed data with TCP in stateful mode and raw IP (protocol 99) in stateless mode. · Migration mode supports both types of tunnels: legacy and enhanced. Use this mode when migrat ing from earlier versions of PacketWise. By default, 50 percent of compression memory is allocated to legacy compression tunnels and 50 percent is assigned to enhanced Xpress tunnels. This ratio can be modified. The default mode for new installations is enhanced mode; see "Using Enhanced Tunnel Mode" on page 10. The default mode for units that have upgraded to 8.x is migration mode, in most cases; see "Migrating to Xpress 8.x" on page 3. The exception is when watch mode is enabled before the upgrade. If watch mode is enabled in 7.x, the unit will be in legacy mode after the upgrade. (This is because watch mode only operates in legacy mode.)

Requirements and Limitations

See PacketGuide for details on Xpress feature requirements and limitations.

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First Steps to Using Xpress

Migrating to Xpress 8.x

This section is applicable to existing PacketShaper Xpress deployments that are upgrading to v8.x. For new installations, skip this section and go directly to "Using Enhanced Tunnel Mode" on page 10.

Migration Mode

When you upgrade to v8.x, PacketShaper is automatically in migration mode. In migration mode, the enhanced Xpress code (v8.x) and legacy compression code (included in 6.x/7.x) run in parallel. PacketShapers in migration mode will be able to create compression tunnels with units running 6.x/7.x software and compress data between these units. In addition, units with migration mode enabled can create Xpress tunnels with units running 8.x software and compress, pack, and accelerate data between these units. Migration mode is useful for upgrading PacketShapers from 6.x/7.x versions of PacketWise to the new Xpress capabilities in PacketWise v8.x. Migration mode is intended to be a temporary, transitional mode of operation. For best results and to take advantage of all the capabilities Xpress offers, it is important to move to enhanced mode as soon as possible. This section describes the best way to accomplish the migration. Migration mode has full support of legacy functionality and a subset of support for enhanced functionality. · Legacy functionality: As in previous versions of Xpress, compression tunnels will automatically form with autodiscovered Xpress partners. Compression tunnels are formed with partners that are running PacketWise v8.x in legacy mode, v8.x in migration mode, or v6.x/7.x. Note that compression must be enabled on both PacketShapers for a tunnel to be formed between them. All of the compres sionrelated CLI commands (such as class compress and setup compression) are available. · Enhanced functionality: Unlike in enhanced mode, migration mode's enhanced Xpress tunnels will not form automatically because the mechanism for autodiscovery of hosts and partners for en hanced tunnels is not available. Enhanced Xpress tunnels must be manually configured in migration mode. In addition, hosts must be assigned to each tunnel using CLI commands (tunnel remote add and tunnel local add). However, all other enhanced mode functionality is available: transport accel eration, HTTP acceleration, tunnel monitoring and configuration via the new Xpress tab, ability to override global settings on a pertunnel basis, a new set of tunnelrelated CLI commands, and so forth.

Migration Procedure

If you are upgrading to 8.x so that you can use the enhanced Xpress features, Packeteer recommends using the following migration procedure: 1. 2. 3. 4. 5. 6. 7. 8. Starting with one remote site, upgrade PacketShaper to v8.x. Verify legacy compression tunnels are working. Set enhanced tunnel options. Upgrade a partner unit to v8.x. Set tunnel passwords. Test enhanced tunnels (using manuallycreated tunnels) and verify compression is working. Upgrade all units to v8.x. Switch to enhanced mode on all units. Note: Details for each step are described in the following pages. This procedure assumes that you have been running Xpress successfully on your network using PacketWise v7.x software. It is also assumed that XpressIP addresses have been configured and compression has been enabled.

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Step 1: Upgrade One Site to PacketWise v8.x

Decide which PacketShaper would be best for the initial 8.x installation; most likely this will be one of your remote sites. Once you have selected the initial unit, you can load the 8.x software on it. Download the software image file from the Packeteer support website (http://www.packeteer.com/support/ down_main.cfm) to your client workstation and then FTP the file to the PacketShaper. You can then load the new software image using the image load command in the commandline interface.

Step 2: Verify Legacy Compression

In order for compression to work, XpressIP addresses must be configured on all devices that will be used for compression. The upgrade process will automatically use the same addresses you configured in v7.x. PacketWise 8.x has the additional requirement that the XpressIP address cannot be the same as the management IP address. If they are the same, you will see the following error message on the Info tab (in the browser) or in the CLI banner after you log in: Warning: No XIP addresses have been configured. Compression will not work until you configure the XpressIP addresses. You can view and change XpressIP addresses using the new Xpress tab in v8.x: 1. 2. 3. Click the xpress tab. Click xpressip settings. The XpressIP Settings window appears. For each network interface (builtin or LEM) you want to use for Xpress tunneling, fill in the following information:

Field IP Address

Description Xpress-IP address to assign to the interface; each interface must have a unique address. Note that this address is used by the Xpress feature and is not for managing the PacketShaper. An Xpress-IP address can NOT be the same as the unit's management address or customer portal address. Subnet mask (for example, 255.255.0.0) IP address of the router; leave blank or enter none if there is no gateway. The gateway is required in the following situations: If the tunnel partner is not on the same subnet - or If acceleration is enabled and the TCP connection endpoints are not on the same subnet as the XIP address

Net Mask Gateway

4. 1. 2.

Click OK to update the settings. Click the xpress tab. Click global tunnel settings. The Edit Global Tunnel Settings window appears. Note: The Tunnel Mode should be set to Migration.

Make sure legacy compression is enabled:

3. 4.

Set Legacy Compression to on. Click OK.

To verify legacy compression is working and compression tunnels are being established, use the setup compression show command in the CLI. The output should show that compression is enabled, list the IP address and status of active tunnel partners, and list details about the services that have active flows being compressed. For example:

setup compression show

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Tunnel Interface: Tunnel Partner: Tunnel Status: Tunnel Quality: Tunnel Savings:

main 192.21.0.85 Compressing (Up: 30m 54s, Idle: 1s) 100 33 KBpm

Compressors Type %Bytes Saved -----------------------------------------------------------------------------GROUP DICTIONARY cna-1M 38% ( 1 secs old) NetBIOS-IP-SSN cna-1M 38% ( 1 secs old) DNS cna-1M 3% ( 22 secs old) KaZaA-Cmd cna-1M 45% ( 50 secs old) DCOM cna-1M ----% (126 secs old) Observed cna-1M 29% ( 60 secs old) Compression: On Memory: 1282 KB / 318750 KB Tunnels: 1 Active, 0 Idle, 1 Total

Step 3: Set Enhanced Tunnel Options

Your settings for the DiffServ interoperability and firewall support variables were automatically carried forward during the upgrade process. These variables apply to legacy compression only. The corresponding settings for enhanced tunnels can be set via the Xpress tab, as described below. 1. 2. 3. 4. Click the xpress tab. The current global settings are displayed next to the global tunnel settings button. Click global tunnel settings. The Edit Global Tunnel Settings window appears. Set Compression to on. (The Compression setting applies to enhanced tunnels.) Set global options: Description Enable firewall support if the PacketShaper will be sending or receiving tunneled traffic through a firewall. Enable DiffServ mode when using compression or packing on a DiffServ network. If an Xpress tunnel has DiffServ enabled, Xpress will inspect all packets for its DiffServ Code Point (DSCP) value. Within the tunnel, it will create a separate lane for each DSCP value. When Xpress sees packets with a DSCP different from those seen before, it will create a new lane associated with that DSCP. Any packets with that DSCP are then sent through the associated lane. Notes: When DiffServ mode is enabled, the tunneled super packets will inherit the DiffServ markings of the original packets. If a super packet is marked with a different DSCP value while it's inside the MPLS network, the partner PacketShaper at the other end of the tunnel will remark each of the original packets with this new value. Xpress supports up to five DSCP values. If your network exceeds the maximum, the super packets in the tunnel will not have DiffServ markings. However, if the super packet is marked with a different DSCP value while it's inside the MPLS network, the partner PacketShaper will remark each of the original packets with the new value.

Feature Firewall

DiffServ

Discovery

Enable/disable the auto-discovery of hosts and partners on all Xpress tunnels. Note: In migration mode, Discovery is disabled because this feature operates in enhanced mode only. Most likely, you will want to enable Discovery after switching to enhanced mode.

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Feature Maintenance

Description Check the availability of remote hosts by sending maintenance probe packets if a host hasn't responded through the tunnel during the last 30 seconds. Maintenance probes are recommended when direct standby is enabled in enhanced tunnel mode. When maintenance probes are enabled, Xpress will send a probe packet to non-responsive hosts on a tunnel's remote list, to make sure they are still available through the existing tunnel. If the host doesn't respond to the probe (perhaps because a link is down), Xpress will use an alternate path (available via the direct standby connection) to tunnel the traffic to the host. Note that if bidirectional traffic to/from a host goes through the tunnel continuously, the maintenance probes are not sent; they are sent only if a host hasn't responded during the last 30 seconds. Once Xpress receives a tunneled packet from the remote host, the 30-second timer will be reset.

MTU

Set the Maximum Transmission Unit (MTU) used for packing and acceleration. The MTU defines the maximum size of the super packet -- it's the largest datagram than can be transmitted by an IP interface, without it needing to be broken down into smaller units. Valid MTU values are 100-1500; the default is 1500. Or choose auto to let the system pick the MTU automatically.

5.

Click OK.

Step 4: Upgrade a Partner Unit

To verify that enhanced tunnels are functioning properly, you'll need to upgrade and configure a partner PacketShaper following the same steps as you did for the initial unit.

Step 5: Set Tunnel Passwords

For security purposes, you should configure a community password for Xpress tunnels. This authentication mechanism is used to determine whether tunnel partners can be "trusted" for purposes of receiving host updates. When tunnel partners have matching passwords, the tunnels will be in secure mode and will exchange host updates. Follow these steps to set the same password on each Xpress partner: 1. 2. 3. 4. 5. Click the xpress tab. Click global tunnel settings. The Edit Global Tunnel Settings window appears. In the Password field, type the tunnel password. Passwords can be up to nine characters long and are case sensitive. They can consist of a combination of letters, numbers, and all special characters. In the Retyped Password field, type the password again. Click OK.

Don't forget to repeat the above steps for the partner unit.

Step 6: Test Enhanced Tunnels

In enhanced mode, Xpress is able to autodiscover tunnel partners and hosts and therefore tunnels are created automatically. In migration mode, legacy compression tunnels are autodiscovered but enhanced tunnels must be manually configured. Before switching to enhanced mode, you'll want to define an enhanced tunnel to make sure it is able to form and then verify that it is compressing data. To define a tunnel, you must assign it a name, specify the tunnel partner's XpressIP address, and indicate on which device (builtin or LEM) that the tunnel will be formed. If you want the tunnel to have special parameters different from the default settings, you can change the settings while creating the tunnel. To create a static tunnel:

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1. 2. 3.

Click the xpress tab. Click add tunnel. The Add Tunnel window appears. Enter a descriptive Name for the tunnel. The name can be up 24 characters long and may include alphanumeric characters and the following special characters: . _ : @ $ % = + [ ] { } Spaces are not allowed. For Partner IP, specify the XpressIP address of the partner PacketShaper. For Device, select the device to configure on the local unit: main-- built-in interface upper -- upper LAN Expansion Module (LEM) lower -- lower LEM right -- right LEM left -- left LEM

4. 5.

6. 7.

If you want the tunnel to use all of the default global tunnel settings, you can click OK to create the tunnel. Otherwise, select the appropriate setting for each option. Click OK. The static tunnel will now be listed in the Xpress Tunnels Overview. If you changed any of the default settings, the tunnel name will be italicized.

Add Hosts Since automatic host discovery is not available for enhanced tunnels in migration mode, you will need to assign hosts using the tunnel local add or tunnel remote add commands in the commandline interface. If you specified identical tunnel passwords in Step 5, you will need only to assign local hosts. If you don't assign passwords or the passwords don't match on the partner units, you will need to assign remote hosts. To configure the subnets, host ranges, and individual hosts that are local to a particular physical interface, use the following command:

tunnel local add <device> <host>|<range>|<subnet>/<cidr>|list:<hostlist>

For example: tunnel local add main 10.0.0.0/8 192.168.0.0192.168.0.60 192.168.10.12 Any tunnel formed on that interface will then assume that those hosts are eligible to receive traffic on that tunnel. To add remote hosts to a static Xpress tunnel, use this command:

tunnel remote add <tunnel> <host>|<range>|<subnet>/<cidr>|list:<hostlist>

For example: tunnel remote add tunnel3 192.168.0.0192.168.10.100 Monitor Enhanced Tunnels The Xpress tab provides a convenient way to monitor your enhanced Xpress tunnels. It lists all the enhanced tunnels that have been formed with your PacketShaper and indicates configuration information and statistics for each tunnel.

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To see if the enhanced tunnel you created for testing purposes is actively compressing data, click the xpress tab. The tunnel you created should be listed on the Xpress Tunnels Overview, and statistics should appear in the Outbound and Inbound columns.

On the partner unit, the tunnel should appear as a dynamic tunnel on its Xpress Tunnels Overview.

Step 7: Upgrade All Units to PacketWise v8.x

At this stage, you are ready to upgrade the remainder of your PacketShapers to PacketWise v8.x. If you are managing your units with PolicyCenter, you can use the image distribution feature to upgrade all units at once.

Step 8: Switch to Enhanced Tunnel Mode

Because migration mode has its limitations, the goal is to get all your units running in enhanced mode as soon as possible. 1. 2. 3. 4. 5. Click the xpress tab. Click global tunnel settings. The Edit Global Tunnel Settings window appears. Select Enhanced for the tunnel mode. Click OK. A popup window explains that PacketShaper must be reset to enable the new tunnel mode. Click OK. On the Xpress Tunnels Overview page, the tunnel mode setting doesn't appear to have changed, and a warning icon appears next to the mode.

The new tunnel mode will not take effect until you reset the device. The warning icon will disappear after the reboot and relogin. To reset the PacketShaper: 1. 2. 3. Click the setup tab. From the Choose Setup Page list, choose unit resets. Click reset device and click OK.

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After you log back in, click the xpress tab and verify that the Tunnel Mode is set to Enhanced. At this point you might want to make sure global Discovery is enabled so that enhanced tunnels can be autodiscovered. You can also enable packing and acceleration, if applicable. For more information on using enhanced mode, see the following pages.

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Using Enhanced Tunnel Mode

Note: This section assumes your PacketShapers are running v8.x software in enhanced mode. In enhanced mode, Xpress tunnels are created automatically when all of the following conditions are met: · Tunnel host and partner discovery is enabled. · A flow is destined for a host on the other side of a PacketShaper or a flow is received from a host on the other side of an PacketShaper. · The two PacketShapers are configured outside port to outside port. · An XpressIP address is configured for each PacketShaper device (builtin or LEM) you want to use for Xpress compression, packing, or acceleration. (This configuration is required for automatic and manual tunnels.)

LAN LAN

INSIDE OUTSIDE

WAN or Internet

INSIDE

OUTSIDE

Each unit's OUTSIDE port connected to router

Tunnels that are autodiscovered in this manner are called dynamic tunnels. Optionally, you can manually configure an Xpress tunnel by specifying the device to configure on the local unit (such as the main interface or upper LEM) and the IP address of the partner PacketShaper. Tunnels that you manually create are called static tunnels. Dynamic Xpress tunnels can be converted to static tunnels so that the settings can be fine tuned. Because certain settings (such as manually adding remote hosts) can be configured for static tunnels only, you'll need to convert the tunnel to static if you want to adjust these settings.

Defining Xpress-IP Addresses

Xpress compression and acceleration require that each network interface (builtin and LEMs) on the PacketShaper be assigned a unique IP address, called an XpressIP address. The XpressIP (XIP) address is used for establishing tunnels between PacketShapers. Until you assign XIP addresses, PacketWise will not be able to set up tunnels for compression, packing, or acceleration. If you haven't already done so, follow these steps to configure XpressIP addresses: 1. 2. Click the xpress tab. Click xpressip settings. The XpressIP Settings window appears.

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3.

For each network interface (builtin or LEM) you want to use for Xpress tunneling, fill in the following information: Description Xpress-IP (XIP) address to assign to the device; each device must have a unique address on the appropriate network segment. Note that this address is used by the Xpress feature and is not for managing the PacketShaper. An XIP address can NOT be the same as the unit's management address or customer portal address. Subnet mask (for example, 255.255.0.0) IP address of the router; leave blank or enter none if there is no gateway. The gateway is required in the following situations:

Field IP Address

Net Mask Gateway

If the tunnel partner is not on the same subnet If acceleration is enabled, and the TCP connection endpoints are not on the same subnet as the XIP address

- or

In most cases, the XIP gateway will need to be configured. For VLAN networks only: (optional parameters) VLAN ID 802.1Q VLAN ID (0 - 4095) Note: A maximum of three VLAN IDs can be assigned per PacketShaper (one for each device). VLAN Priority 802.1P VLAN priority (0-7) If your network isn't using VLAN IDs but you want to set a VLAN priority, you must set a VLAN ID of 0 (zero) before you can select a priority. 4. Click OK to update the settings.

Enabling/Disabling Tunnel Features

As part of Xpress configuration, you need to configure the default settings for tunnel features and options. As dynamic and static tunnels are created, they will inherit these default settings. On the Global Tunnel Settings page, you can globally enable one or more of the following tunnel features: acceleration, compression, and/or packing. In addition, you can set the default options for your tunnels: firewall support, DiffServ support, automatic host and partner discovery, and MTU size. To set default settings for tunnel features: 1. 2. 3. Click the xpress tab. The current global settings are displayed. Click global tunnel settings. The Edit Global Tunnel Settings window appears. Turn on/off the features you want to enable/disable globally: Description Xpress acceleration allows you to maximize bandwidth utilization, speed up application response times, accelerate the transfer of large files, and minimize the impact of other problems that are common on high-latency links (such as satellite links).

Feature Acceleration

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Feature Prefetch (client) Prefetch (server)

Description (Available when acceleration is enabled) The Prefetch feature reduces the time required to download and display web pages. The Prefetch client mechanism intercepts browser connections destined to ports 80 and 8080, and attempts to match them with connections already in the process of delivering content from the remote PacketShaper. The Prefetch server mechanism operates on the PacketShaper closest to the web server; it inspects all content returning from connections to ports 80 and 8080, tries to find and prefetch any embedded objects that the browser will probably request, and will immediately start pushing that content back towards the browser-side PacketShaper. The Prefetch client and server can be enabled/disabled independently. For prefetching to work, Prefetch client support must be enabled on the PacketShaper closest to the browser machines, and Prefetch server support must be enabled on the PacketShaper closest to the web server. If there are web servers on both sides of the link and you want to provide prefetching for web connections in both directions, you can enable Prefetch client and server on both PacketShapers. Note: When Prefetch is enabled, the PacketShaper and partner must be configured with the address of at least one DNS server. If more than one DNS server is configured, the Prefetch logic will spread its requests equally among them.

FastStart

(Available when acceleration is enabled) The FastStart feature accelerates web downloads by reducing the time needed to establish each new HTTP connection. Using FastStart, Xpress acknowledges TCP connections immediately without waiting for a connection to be established to the web server. This immediate acknowledgment allows the browser to send its HTTP GET request right away. Xpress then combines the HTTP GET request with the XTP connection request. This process delivers the HTTP request to the web server one round-trip faster. For web pages that consist of large numbers of objects, FastStart greatly improves the responsiveness of the web page display. FastStart is enabled by default. There is typically no need to disable FastStart unless you are using SCPS.

SCPS

(Available when acceleration is enabled) When SCPS (Space Communications Protocol Standards) is enabled, it becomes the transport protocol for the transmission of data over the satellite portion of the link.

Compression

Xpress compression shrinks the size of transferred traffic, effectively increasing the amount of bandwidth available on a link. When Xpress packing is enabled, multiple packets are combined into a single super packet before being sent through the Xpress tunnel. Notes: The maximum size of the super packet is determined by the MTU. Packing is most efficient and effective when dealing with small packets or packets that can be reduced in size with compression.

Packing

4.

Click ok.

Setting Global Tunnel Options

Through the global tunnel options, you can set default values for firewall support, DiffServ support, auto discovery of hosts and tunnel partners, and MTU size.

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To set default settings for tunnel options: 1. 2. 3. Click the xpress tab. The current global settings are displayed next to the global tunnel settings button. Click global tunnel settings. The Edit Global Tunnel Settings window appears. Set global options: Description Enable firewall support if the PacketShaper will be sending or receiving tunneled traffic through a firewall. Firewall support is disabled by default. Enable DiffServ mode when using compression or packing on a DiffServ network. If an Xpress tunnel has DiffServ enabled, Xpress will inspect all packets for its DiffServ Code Point (DSCP) value. Within the tunnel, it will create a separate lane for each DSCP value. When Xpress sees packets with a DSCP different from those seen before, it will create a new lane associated with that DSCP. Any packets with that DSCP are then sent through the associated lane. Discovery Maintenance Enable/disable the auto-discovery of hosts and partners on all Xpress tunnels. Check the availability of remote hosts by sending maintenance probe packets if a host hasn't responded through the tunnel during the last 30 seconds. Maintenance probes are recommended when direct standby is enabled in enhanced tunnel mode. When maintenance probes are enabled, Xpress will send a probe packet to non-responsive hosts on a tunnel's remote list, to make sure they are still available through the existing tunnel. If the host doesn't respond to the probe (perhaps because a link is down), Xpress will use an alternate path (available via the direct standby connection) to tunnel the traffic to the host. Note that if bidirectional traffic to/from a host goes through the tunnel continuously, the maintenance probes are not sent; they are sent only if a host hasn't responded during the last 30 seconds. Once Xpress receives a tunneled packet from the remote host, the 30-second timer will be reset. MTU Set the Maximum Transmission Unit (MTU) used for packing and acceleration. The MTU defines the maximum size of the super packet -- it's the largest datagram than can be transmitted by an IP interface (without it needing to be broken down into smaller units). Valid MTU values are 1001500; the default is 1500. Or choose auto to let the system pick the MTU automatically.

Feature Firewall

DiffServ

Monitoring Tunnels

To see the dynamic tunnels that the Discovery feature has created, go to the Xpress tab and look at the Xpress Tunnels Overview. Static tunnels you have manually defined, as well as dynamic tunnels you have converted to static, are also listed here. It lists all the enhanced tunnels that have been formed with your PacketShaper and indicates configuration information for each tunnel: name, functionality (Compression, Packing, Acceleration), the IP address of the Xpress partner, and whether it's static or dynamic. Dynamic tunnels will have names that identify the endpoints of the tunnel: the partner's IP address and the device (such as main or upper) on the local unit, for example, 172.21.18.160:Main.

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In addition, the Xpress tab displays Inbound and Outbound statistics for each tunnel: speed before and after compression/decompression, percentage of bytes saved due to compression, and rate of accelerated traffic. If there is a problem with the tunnel, a warning icon will appear next to the tunnel name.

Viewing the Compression Summary

The Xpress tab gives pertunnel statistics. If you would like a report on how compression is performing overall on your link, you can display the Compression Summary report. The top of this report has a table that summarizes compression statistics for the Inbound and Outbound links. The Inbound statistics represent inbound traffic that gets decompressed by Xpress, and the Outbound statistics represent outbound traffic that Xpress compresses. This report contains a total of eight graphs -- four graphs for the Inbound direction and four for Outbound. The graphs compare bandwidth usage, with and without compression, so that you can quickly see the amount of compression on your link. To see a meaningful Compression Summary, wait approximately an hour after enabling compression before viewing the report. To display the compression summary: 1. 2. Click the report tab. Click compression summary. The Compression Summary report displays in the current window. Note: By default, only compressible traffic is included in the graphs and data. If you want to show all traffic (compressible and non-compressible), select the include non-compressible traffic in graphs and data checkbox. When this checkbox is selected, you may also want to select the include link size in graphs checkbox. (Link size is less meaningful when viewing only some of the traffic, as is the case when noncompressible traffic is not included.) 3. Adjust the time period and end date, if desired.

The top of the Compression Summary report has a table that summarizes compression statistics for the Inbound and Outbound links. Each statistic is described below: Statistic Precompression Bytes Description Outbound: For compressible outbound traffic, the number of bytes before compression has been applied Inbound: For inbound compressed traffic, the number of bytes after decompression

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Statistic Postcompression Bytes

Description Outbound: For outbound traffic sent through a compression tunnel, the number of bytes after compression has been applied Inbound: For inbound compressed traffic, the number of bytes before decompression

Bytes Saved

The number of bytes that didn't have to traverse the link, due to compression; allows you to see how many bytes the compression feature actually saved on the link. Bytes Saved is the difference between precompression bytes and postcompression bytes. For traffic sent through a compression tunnel, the percentage of bytes saved, due to compression For traffic sent through a compression tunnel, the percentage by which virtual bandwidth is increased due to compression

% Bytes Saved Bandwidth Multiple

Here's an example of one of the compression graphs in the Compression Summary.

The Compression Summary report contains the following graphs: Graph Average Rates Description Compares average bandwidth usage of compressible traffic, with and without compression. The Tunneled Postcompression Average Rate line represents usage with compression enabled, and the Tunneled Precompression Average Rate line represents what average usage would have been without compression. If you enable the include non-compressible traffic in graphs and data checkbox, the graph includes all traffic (compressed and non-compressible) and compares Postcompression Average Rate with Precompression Average Rate. Peak Rates Compares peak bandwidth usage of compressible traffic, with and without compression. The Tunneled Postcompression Peak Rate line represents usage with compression enabled and the Tunneled Precompression Peak Rate line represents what peak usage would have been without compression. If you enable the include non-compressible traffic in graphs and data checkbox, the graph includes all traffic (compressed and non-compressible) and compares Postcompression Peak Rate with Precompression Peak Rate.

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Graph Compression

Description Shows the total number of bytes recorded on the link, with and without compression. The Tunneled Postcompression Bytes line shows the number of bytes that went through a compression tunnel. The Tunneled Precompression Bytes line represents the number of bytes that would have passed through the link if compression weren't enabled. The Bytes Saved line shows the number of bytes that didn't have to traverse the link, due to compression; it's the difference between precompression and postcompression bytes.

If you enable the include non-compressible traffic in graphs and data checkbox, the graph includes all traffic (compressed and non-compressible) and compares Postcompression Bytes with Precompression Bytes. This graph includes an additional line, Non-compressible Bytes, which shows the number of bytes that PacketWise did not attempt to compress, either because they didn't belong to a compressible service or because they were destined for a location without an Xpress partner. Percent Bytes Saved Shows the percentage of bytes saved on the link, due to compression. The Tunneled Percent Bytes Saved value is calculated by subtracting tunneled postcompression bytes (the size after compression) from tunneled precompression bytes (the size without any compression) and dividing this difference by tunneled precompression bytes. For example, if a link would have had 700k without compression and is 400k after being compressed, the Tunneled Percent Bytes Saved would be approximately 43%: (700-400)/700. If you enable the include non-compressible traffic in graphs and data checkbox, the graph includes all traffic on the link (compressible and non-compressible). The Percent Bytes Saved value is calculated by subtracting precompression bytes (the size without any compression) and postcompression bytes (the size after compression) and dividing this difference by precompression bytes. For example, if the link in the example above had 100k of non-compressible traffic, the Percent Bytes Saved would be 38%: ((700+100)-(400+100))/(700+100). If your Compression Summary doesn't show any compression data, see "Compression Problems?" on page 17.

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Displaying the Acceleration Summary

For an overview of how acceleration is working on your link, you can display the Traffic Acceleration Summary report. There is one graph for the Inbound direction and another for Outbound. Each graph displays bandwidth utilization of accelerated bytes that went through Xpress tunnels. A red horizontal line above the graph indicates the periods that acceleration was enabled during the time period.

To display the acceleration summary: 1. 2. 3. 4. Click the report tab. Click acceleration summary. The Traffic Acceleration Summary report displays in the current window. To display the link size as a horizontal green line on each graph, select the include link size in graphs checkbox and click update. Adjust the time period and end date, if desired.

Compression Problems?

If your compression reports don't show any results, check the table below for possible problems and solutions. Problem Cables are connected backwards. Solution Refer to the chapters earlier in this guide for instructions on connecting your PacketShaper to the network. If you discover that you have miscabled the unit, reconnect the cables properly, and then turn compression off and back on. Make sure compression is enabled on the PacketShaper in front of the host.

You are not sending/receiving flows to/from a host on the other side of a compression-enabled PacketShaper. Compression is not enabled on the partner unit(s).

Xpress can't compress data unless the partner unit has also turned on compression. Log in to each of the partner units and go to the xpress tab and make sure Compression is set to on.

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Problem Xpress-IP settings are not configured.

Solution Xpress will not create tunnels or compress data for devices (main or LEM) that are not configured with Xpress-IP (XIP) settings. To configure XIP settings for each device, go to the xpress tab and open the Xpress-IP Settings page. Note: In PacketWise v8.x, the XIP cannot be the same as the management IP address. If the addresses were the same when you upgraded from 7.x, the XIP address will be cleared and compression will be disabled.

The Compression Summary shows little compression savings.

Enable the checkbox include non-compressible traffic in graphs and data and click update. Look at the Non-compressible Bytes line in the Compression graph. If this line shows that non-compressible bytes are at about the same level as precompression bytes, most of the traffic on your link is not compressible. This could be because: the traffic is destined to sites without Xpress. Make a site-based traffic tree, creating classes for each of your branch offices. Look at compression reports for each class. If no traffic is being compressed to a site, it's possible that there is no PacketShaper, compression is not turned on, or Xpress-IP settings haven't been configured. or the applications are non-compressible. Go to the Top Ten page and make note of the top Outbound classes. Examples of non-compressible applications are streaming media and encrypted data. View Class Compression Bytes Transferred graphs for each class and enable the checkbox Include Non-Compressible Traffic in Compression Graphs. If the Non-compressible Bytes line is at about the same level as the Precompression Bytes line, most of the traffic in the class is not compressible.

Some traffic isn't getting compressed.

To see the reasons why traffic isn't being compressed, you can look at the Non-Compressible Traffic graph. On the Compression Summary, enable the checkbox include non-compressible traffic in graphs and data and click update. Click the Non-compressible traffic breakdown link. The Non-Compressible Traffic line graph indicates the amount of traffic that was non-compressible due to each of the following reasons: Compression Disabled -- Compression was not enabled (for example, a particular tunnel had compression disabled so none of the traffic in the tunnel was compressed). Traffic Policy -- The traffic was classified as a non-compressible service, compression was disabled for the service or class, or the traffic was broadcast or multicast. (Note: Multicast traffic won't be compressed unless the Class D addresses are added to remote and/or local host lists.) System Availability -- There was insufficient compression memory to tunnel the traffic or the CPU was too busy. No Tunnel for Host -- Hosts were restricted from using compression, partners were excluded from using compression, a tunnel partner wasn't found, or hosts were not discovered.

You applied a never-admit policy to the RSVP class.

The tunnel discovery process will not function if the RSVP class has a never-admit policy. Delete the policy.

If you are still experiencing problems with compression after trying the above solutions, use the tunnel show and tunnel compression show commands in the commandline interface. These commands provide tunnel partner status. PacketGuide provides additional troubleshooting details -- just search for tunnel troubleshooting.

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Acceleration Problems?

If your acceleration report doesn't show any data being accelerated, check the table below for possible problems and solutions. Problem Cables are connected backwards. Solution Refer to the chapters earlier in this guide for instructions on connecting your PacketShaper to the network. If you discover that you have miscabled the unit, reconnect the cables properly, and then turn acceleration off and back on. Make sure acceleration is enabled on the PacketShaper in front of the host, or that a SkyX device is in front of the host.

You are not sending/receiving flows to/from a host on the other side of an acceleration-enabled PacketShaper or a SkyX device. Acceleration is not enabled on the partner unit(s).

Xpress can't accelerate data unless the partner unit has also turned on acceleration. Log in to each of the partner units and go to the xpress tab and make sure Acceleration is set to on. Xpress will not create tunnels or accelerate data for devices (main or LEM) that are not configured with Xpress-IP (XIP) settings. To configure XIP settings for each device, go to the xpress tab and open the Xpress-IP Settings page. Note: In PacketWise v8.x, the XIP cannot be the same as the management IP address. If the addresses were the same when you upgraded from 7.x, the XIP address will be cleared.

Xpress-IP settings are not configured.

A site router is configured. You applied a never-admit policy to the RSVP class.

Acceleration won't work if a site router is configured. Set the site router to none. The tunnel discovery process will not function if the RSVP class has a never-admit policy. Delete the policy.

If you are still experiencing problems with acceleration after trying the above solutions, use the tunnel show and tunnel acceleration show commands in the commandline interface. PacketGuide provides additional troubleshooting details -- just search for tunnel troubleshooting.

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