Apposite Technologies Linktropy Mini2 User manual

LINKTROPY®MINI2&MINI-G™
WAN EMULATOR
USER’S GUIDE
Firmware Version 3.0
®

Linktropy® Mini2& Mini-G™WAN Emulator User’s Guide
Revision 4d, August 2017
Apposite®Technologies LLC
11500 W. Olympic Blvd., Suite 510
Los Angeles, CA 90064 USA
1.310.477.9955
[email protected]
www.apposite-tech.com
Copyright ©2005-2017 Apposite Technologies LLC. All rights reserved. Apposite, Linktropy, and Netropy are registered
trademarks of Apposite Technologies LLC. The Apposite logo and “WAN Emulation Made Easy” are trademarks of
Apposite Technologies LLC.
Part No. DOC-UG-LM2G-4C

CONTENTS
1 Overview ...........................................................................................................................................................................................4
1.1 Linktropy Product Family..............................................................................................................................................4
1.2 Linktropy Operation........................................................................................................................................................6
1.3 Linktropy Configuration ................................................................................................................................................7
2 Getting Started: Installing the Linktropy WAN Emulator...........................................................................................8
3 Linktropy GUI ............................................................................................................................................................................... 11
3.1 Overview........................................................................................................................................................................... 11
3.2 Status Box ........................................................................................................................................................................ 12
3.3 Emulation On/Off Button........................................................................................................................................... 12
3.4 Message Bar.................................................................................................................................................................... 13
4 Link Emulation Tab: Link Emulation Parameter Configuration ............................................................................. 14
4.1 Basic Parameters ........................................................................................................................................................... 16
4.1.1 Bandwidth....................................................................................................................................................... 16
4.1.2 Delay ................................................................................................................................................................. 16
4.1.3 Loss.................................................................................................................................................................... 17
4.2 Advanced Parameters ................................................................................................................................................. 17
4.2.1 Queue Depth ................................................................................................................................................. 18
4.2.2 Framing Overhead....................................................................................................................................... 18
5 Bridge/Route Tab: Bridge and Routing Mode Configuration ............................................................................... 19
5.1 Bridging Mode............................................................................................................................................................... 19
5.1.1 Emulation Bypass ......................................................................................................................................... 20
5.1.2 Learning Bridge............................................................................................................................................. 20
5.2 IP Routing Mode........................................................................................................................................................... 20

5.2.1 IP Addresses................................................................................................................................................... 21
6 Device Settings Tab: Device and Interface Parameters............................................................................................ 23
6.1 Device Name................................................................................................................................................................... 24
6.2 MGMT Interface............................................................................................................................................................. 24
6.3 Management Access ................................................................................................................................................... 24
6.4 Ethernet Ports................................................................................................................................................................. 25
7 Save / Load Tab: Save, Load, and Delete Named Emulations............................................................................... 26
7.1 Save Emulation .............................................................................................................................................................. 27
7.2 Load Emulation.............................................................................................................................................................. 27
7.3 Delete Emulation........................................................................................................................................................... 28
8 Upgrade Tab: Firmware Upgrades and License Keys................................................................................................ 29
8.1 Upgrade Firmware........................................................................................................................................................ 29
8.2 License Key ...................................................................................................................................................................... 30
9 Linktropy Monitor ...................................................................................................................................................................... 31
9.1 Statistics............................................................................................................................................................................ 31
9.2 ARP Table......................................................................................................................................................................... 33
10 Security ........................................................................................................................................................................................ 34
10.1 Passwords...................................................................................................................................................................... 34
10.2 SSL.................................................................................................................................................................................... 34
10.3 SSH................................................................................................................................................................................... 34
11 Command Line Interface....................................................................................................................................................... 35
12 Apposite Support..................................................................................................................................................................... 38
Appendix A: Linktropy End User License Agreement.......................................................................................................... 39
Appendix B: Third Party Licenses ................................................................................................................................................ 42

1OVERVIEW
Thank you for purchasing the Apposite Technologies Linktropy Mini2or Linktropy Mini-G WAN
Emulator. This User’s Guide describes the installation, configuration, and operation of the
Linktropy functionality. Please consult the companion Hardware Guide for information on the
Linktropy Mini2or Mini-G hardware. A separate Quick Start Guide provides a walk-through for first
time configuration.
1.1 Linktropy Product Family
The Linktropy Mini2and Mini-G are portable, low cost members of the Linktropy WAN Emulator
product family, designed primarily to emulate basic WAN conditions for customer demonstrations
of networking products and application development of client/server systems. Their small size
and light weight make them easy to carry, while their fanless design and solid-state storage offer
extra reliability for frequent shipping. The Linktropy Mini2has 10/100baseT Ethernet ports and is
limited to 100 Mbps while the Mini-G includes Gigabit Ethernet ports with higher throughput and
packet forwarding rates.
The Linktropy Mini2and Mini-G are not designed to provide the same level of precision,
performance, and functionality as the Linktropy 5510 and 8510 which are built as professional test
tools for lab testing and product validation. The table on the next page shows the matrix of
features for the different products in the Linktropy product family.
SECTION 1OVERVIEW 4

Linktropy Model Mini2 Mini-G 5510 8510
Performance
Maximum throughput per link (full duplex) 100 Mbps 1 Gbps 1 Gbps 1 Gbps
Emulated links 1 1 1 4
Maximum packet forwarding rate (pps) 80,000 350,000 3 million 12 million
Test lab level precision XX
Jumbo Frame Support (up to 9 KB) X
Link Impairment Emulations
Bandwidth 
Latency (constant, uniform, and normal
distributions) 
Packet Loss 
Bit Errors 
Background Traffic XX
Packet Duplication XX
Packet Reordering XX
Live condition capture and replay XX
Linktropy Scheduler for dynamic conditions XX
Installation
Record and download traffic statistics XX
Install as Bridge 
Install as Router 
Emulation interfaces 2 FE
10/100baseT
2 GigE
RJ45
2 GigE
RJ45 or SFP
8 GigE
RJ45 or SFP
Form factor compact compact 1U 1U
Hardware warranty and software maintenance 1 year 1 year 1 year 1 year
Customer support 90 days 90 days 1 year 1 year
SECTION 1OVERVIEW 5

1.2 Linktropy Operation
The Linktropy Mini2and Mini-G emulate a wide area network link between two local networks.
Depending on configuration, the Linktropy device is installed as either a bridge or a router
between the Ethernet segments connected to the LAN A and LAN B ports of the unit. Frames
received on one port are subjected to the emulated WAN conditions before being forwarded to
the opposite port.
Frames are processed by the Linktropy WAN Emulator in the following steps:
1. Ethernet frames arrive on the LAN A or LAN B interface of the Linktropy emulator.
2. The effective size of the frame is calculated as the data portion of the Ethernet frame (without
the Ethernet header or FCS) plus the configured value for framing overhead.
3. Frames are throttled to the specified WAN bandwidth. Frames in excess of the specified WAN
bandwidth are queued to the configured maximum queue depth. When the queue is full,
newly-arriving frames are discarded.
4. Frames are subjected to random discard based on the configured packet loss and bit error
parameters.
5. Frames remaining after the discard procedure are held for the specified link delay. Frames are
not reordered in this step, even if subjected to differing delays. For example, if the delay is
specified as a uniform distribution between 10 and 100 ms and the first frame is subjected to
a 90 ms delay and the second frame is subjected to a 20 ms delay, the second frame can not
be transmitted until after the first frame has been transmitted. This effect can skew the
measured mean delay to be higher than the configured value when using a normal or
uniform distribution.
6. Frames are bridged or routed to the opposite LAN interface and transmitted to the
destination address.
Frames are subject to three separate delays:
1. Propagation delay: Delay caused by the distance the signal travels. This delay is emulated as
the specified link delay.
2. Queuing delay: If frames arrive faster than they can be transmitted over the WAN link, they
are held awaiting their slot for transmission. The actual queuing delay will vary depending on
how quickly frames arrive compared to how quickly they can be transmitted. The maximum
queuing delay is determined by the maximum queue depth, which can be set in milliseconds,
bytes, or packets.
3. Transmission delay: The time to transmit the individual bits in each frame is an additional
delay that can be significant for large frames over low speed links. For example, the
transmission of a 1500 byte frame over a 9,800 bps link adds 1.25 seconds. The transmission
delay is fixed by the frame size and link bandwidth.
SECTION 1OVERVIEW 6

SECTION 1OVERVIEW 7
Only the propagation delay is specified directly as an emulation parameter. The end-to-end delay
is the sum of the three individual delays.
Frames are subject to three separate types of loss:
1. Emulated packet loss: Frames are randomly discarded based on the specified packet loss rate.
Since frame discard occurs after the frames have been rate throttled, discarded frames will
consume link bandwidth.
2. Emulated bit errors: Frames are randomly discarded based on the specified bit error rate.
Since this discard also occurs after the frames have been rate throttled, discarded frames will
consume link bandwidth.
3. Queue drops: If frames arrive faster than they can be transmitted over the emulated link,
excess frames will be queued to the specified maximum queue depth. Once the queue is full,
additional frames are discarded. These dropped frames do not consume WAN bandwidth.
When functioning as a bridge, the Linktropy WAN Emulator is not limited to emulating IP
networks, but can emulate any type of network so long as the traffic is encapsulated in Ethernet.
In addition to IP, the device can be used with IPv6, IPX, AppleTalk, SCPS, and proprietary network
and transport layer protocols.
1.3 Linktropy Configuration
Configuration of the Linktropy WAN Emulator is primarily through the browser-based Linktropy
GUI (Graphical User Interface). The GUI is accessible from any PC or other device with a standard
web browser. Management connectivity is via a dedicated Ethernet management interface on the
Linktropy WAN Emulator or in-band through the LAN A or LAN B interface. See Section 3 for
more information on the Linktropy GUI.
In addition to the GUI, the Linktropy WAN Emulator includes a limited command line interface
(CLI) that can be accessed via the console serial port or over the network using Telnet or SSH. The
CLI is used primarily to set the management IP address if the GUI is not accessible over the
network, and to load stored emulation conditions for use with script-based automated testing.
See Section 11 for details on the CLI.

2GETTING STARTED:
INSTALLING THE LINKTROPY WAN EMULATOR
The Linktropy WAN emulator is managed through a browser-based GUI over an Ethernet
connection to a dedicated management interface. Prior to operation, this management interface
must be configured with appropriate network settings, either through the Linktropy GUI or
through the command-line interface accessed via the serial console. For convenience, the
management interface comes preconfigured with an IP address of 10.0.0.10, and the GUI is
accessible from a directly-connected host on the 10.0.0.0/255.0.0.0 subnet.
Preparation
Management of the Linktropy WAN emulator requires a PC running a supported web browser
(Internet Explorer, Firefox, Chrome, and Safari). JavaScript must be enabled.
Initial configuration of the management interface requires either:
a PC running a supported web browser that can be configured and placed on the
10.0.0.0/255.0.0.0 network.
a PC with an RS-232 serial port running terminal emulation software such as
HyperTerminal or PuTTY.
Hardware Installation
Plug in the supplied AC to DC power adaptor to the DC power input on the back of the unit. The
Power LED on the front panel will glow green and the system will be available for use within 60
seconds.
For additional hardware installation details, please see the Linktropy Mini2or Linktropy Mini-G
Hardware Guide.
SECTION 2GETTING STARTED:
INSTALLING THE LINKTROPY WAN EMULATOR 8

IP Address Configuration via the Linktropy GUI
To configure the management interface using the Linktropy GUI:
Configure a PC running a supported web browser with the IP address 10.0.0.2 or other
address on the 10.0.0.0/255.0.0.0 subnet.
Connect an Ethernet cable between the PC and the MGMT port of the Linktropy WAN
emulator.
Open the browser on the PC and enter http://10.0.0.10 (the preconfigured management
address) in the address bar. The Linktropy End User License Agreement will be displayed in a
separate window.
Review the License Agreement. The Linktropy GUI will be displayed once the License
Agreement is accepted.
The Linktropy GUI will open to the Device Settings tab. If desired, modify the IP address,
netmask, and default gateway for the management interface. Click the Apply Changes button
when done.
IP Address Configuration via the Serial Console
Using the provided DB-9 cable, connect the serial port of a PC running terminal emulation
software to the CONSOLE port of the Linktropy Mini2. Set the serial port parameters to 9600
baud, 8 bits, no parity, 1 stop bit, and disable flow control. For more details on connecting
to the serial console, see the Linktropy Mini2or Linktropy Mini-G Hardware Guide.
Press [ENTER] to display a login prompt. At the prompt, log in as “admin”. There is no
password.
linktropy login: admin
Use the following commands to set the IP address, IP netmask, and default gateway of the
Linktropy management interface:
mgmt set addr <interface-ip-address> netmask <ip-netmask>
mgmt set gw <default-gateway>
IP addresses and netmasks are entered in dotted-decimal format. For example:
linktropy> mgmt set addr 192.168.1.1 netmask 255.255.255.0
Once the management interface has been configured, use the Ethernet cable to connect the
MGMT port to the management network.
SECTION 2GETTING STARTED:
INSTALLING THE LINKTROPY WAN EMULATOR 9

Operation
The Linktropy WAN emulator is installed between two LAN segments (or two individual devices)
using the ports labeled LAN A and LAN B. The Linktropy WAN Emulator acts as a bridge or
router between those two LAN segments. Frames
received on one port are subjected to the
emulated WAN conditions before being forwarded
to the opposite port.
Emulated WAN conditions are configured in the
Linktropy GUI. To set the emulation parameters,
use a web browser to connect to the Linktropy GUI
at the IP address of the management interface. All emulation parameters are found on the Link
Emulation tab. Emulation is disabled until the “Emulation On/Off” button at the top of the screen
is pressed. See the following chapters for details on Linktropy emulation parameters or click the
buttons on the GUI for information on specific parameters.
Registration
For access to firmware upgrades, documentation, and other support materials, register your unit
on-line at: http://www.apposite-tech.com/register.html.
Registered users will receive email notification whenever new firmware images are released.
SECTION 2GETTING STARTED:
INSTALLING THE LINKTROPY WAN EMULATOR 10

3LINKTROPY GUI
3.1 Overview
The browser-based Linktropy GUI is the primary configuration interface for the Linktropy WAN
emulator. The GUI is compatible with Internet Explorer, Firefox, Chrome, and Safari. JavaScript
must be enabled. The GUI is accessible via HTTP or HTTPS.
The Linktropy GUI consists of a Configuration window and the Linktropy Monitor.
Figure 2: Configuration Window Figure 3: Linktropy Monitor
The Configuration window contains a set of tabs used to specify the emulation parameters and
device settings. Sections 4 through 8 of this User’s Guide describe each of the individual tabs.
The top portion of the Configuration window also includes the Status Box, Emulation On/Off
button, and Message Bar. These elements remain visible across the various tabs.
Each input field is checked for validity when modified. Valid changes are displayed in bold. Invalid
changes are noted with a red box around the field. Additional checks are performed when the
user attempts to apply the changes, and any errors are marked with a red box at that time.
SECTION 3LINKTROPY GUI 11

Clicking any info button opens a Help window with documentation for the specific field.
This User’s Guide is also accessible from any Help window.
The Linktropy Monitor displays real-time statistics and throughput graphs of the traffic traversing
the emulated WAN link. See Section 9 for details on the Linktropy Monitor.
Figure 4: Status Box and Message Bar
3.2 Status Box
The Status Box, at the top right corner of the Configuration window, displays interface status and
basic statistics, and is visible across all tabs.
The Status Box displays the status of the LAN A and LAN B Ethernet interfaces. During normal
operation, the speed and duplex state of the interface are displayed in green. If the interface is
unplugged or fails to negotiate an Ethernet connection, “DOWN” is displayed in red.
When emulation is turned on, the Status Box displays the current instantaneous throughput in
each direction, averaged over 1 second intervals, and the total number of dropped frames. More
detailed statistics and throughput graphs are shown in the Linktropy Monitor.
3.3 Emulation On/Off Button
The Emulation On/Off Button displays and controls the state of the currently selected link. The
button is gray when emulation is off and green when emulation is on. Click the button to toggle
between on and off.
Emulation is turned off by default when the Linktropy WAN emulator is first installed.
SECTION 3LINKTROPY GUI 12

SECTION 3LINKTROPY GUI 13
3.4 Message Bar
The Message Bar, located at the top of the screen, is only visible when status messages are
displayed. Confirmation messages are displayed on a white background, error messages on a red
background, and alerts on a yellow background.

4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION
The Link Emulation tab contains all of the parameters for link emulation. Each parameter can be
configured separately for traffic from LAN A to LAN B and from LAN B to LAN A.
Basic parameter settings are always visible on the Link Emulation tab. Advanced parameters,
which generally only need adjustment for specialized conditions, are hidden by default. To display
the advanced parameters, click the show link. Click the hide link to hide them again if desired.
The active configuration is not modified until the Apply Changes button at the bottom of the tab
is pressed. The Apply Changes button is grayed out when there are no changes to apply. It is also
grayed out if there are any invalid entries. To return to the active configuration without applying
any changes, press the Clear Changes button.
When the Apply Changes button is pressed, final validation of the configuration is performed. If
there are no errors in the configuration, the new configuration will take effect and the message,
“Configuration Updated” will be displayed in the Message Bar. If there are any errors in the
configuration, a red box will be displayed around the invalid field or an error message will be
displayed in the Message Bar.
Advanced parameter settings are used in the emulation, even if the parameters are
hidden.
SECTION 4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION 14

Figure 5: Link Emulation Tab
SECTION 4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION 15

4.1 Basic Parameters
4.1.1 Bandwidth
The Bandwidth row is used to configure the link rate of the emulated WAN.
The link rate is set independently in each direction in increments of 1 bps, with a minimum rate of
300 bps and a maximum rate determined by the license key. Entered rates can not have fractional
bits per second.
The link rate is set in units of bps (bits per second), Kbps (kilobits per second), Mbps (megabits
per second), or Gbps (gigabits per second) selected from the drop-down menu next to the rate.
If the entered link rate is not a valid value when the Apply Changes button is pressed, a red error
box will be drawn around the invalid fields and the changes will not be applied.
1 Kbps is 1,000 bps, not 1,024 bps. Similarly, 1 Mbps is 1,000,000 bps.
4.1.2 Delay
The Delay parameter specifies the link latency in milliseconds, and is set independently for each
direction. Delay can be set from 0 milliseconds to 10 seconds. Entered values are rounded to the
nearest 0.1 millisecond. The delay parameter will not reorder frames.
The radio buttons are used to specify the delay distribution:
Constant: A single, fixed value for delay.
Uniform: A uniform distribution of delay ranging between the configured minimum and
maximum values.
Normal: A truncated normal distribution curve, with a specified minimum, mean and
standard deviation.
If the entered minimum delay is greater than the entered maximum (for a uniform distribution) or
mean (for a normal distribution), a red error box will be drawn around the invalid fields when the
Apply Changes button is pressed and the changes will not be applied.
The round trip time (RTT) of the link is the sum of the delay in both directions.
SECTION 4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION 16

Using the delay parameter, frames are not reordered even if subjected to differing
delays. For example, if the delay is specified as a uniform distribution between 10 and
100 ms and the first frame is subjected to a 90 ms delay and the second frame is
subjected to a 20 ms delay, the second frame will not be transmitted until after the
first frame has been transmitted. This effect can skew the measured mean delay to be
higher than the configured value when using a normal or uniform distribution.
4.1.3 Loss
Data loss rates are configured as bit error rates, packet loss rates, or both. Losses due to packet
loss and bit errors are emulated independently and may be combined to emulate links with
physical layer corruption as well as congestion-induced packet loss.
For a lossless link, set the packet loss rate and bit error rate to 0. The default setting is for a
lossless link.
Packet loss rates can be set from 0 – 100% in increments of 0.0001%.
Bit error rates can take values of 1x10-14 or greater and are entered in scientific notation. The
coefficient of the rate (the field on the left) must be entered as a value greater than or equal to 0
and less than 10. The exponent may be between -1 and -14. The minus sign is supplied and only
the digits of the exponent should be entered in the exponent field.
Losses are assumed to occur over the WAN link itself. Discarded packets therefore consume WAN
bandwidth. For example, if a 1 Mbps link is specified to have a 10% packet loss rate, the maximum
possible average throughput is 900 Kbps.
4.2 Advanced Parameters
To view and configure advanced emulation parameters, click on the show link next to the
Advanced Parameters label. Note that even when hidden, the advanced parameter settings are
used in the emulation. The advanced parameters section cannot be hidden when any of the
entered values are invalid.
SECTION 4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION 17

SECTION 4LINK EMULATION TAB:
LINK EMULATION PARAMETER CONFIGURATION 18
4.2.1 Queue Depth
The Queue Depth row specifies the maximum amount of data that will be buffered when data is
received at a rate exceeding the emulated link rate. Any frames that arrive when the queue is full
are discarded.
The queue depth can be set as a maximum numbers of packets, maximum amount of data in
kilobytes, or a maximum queuing delay in milliseconds. The queue depth is specified separately
for each direction. Valid entries are limited to 10,000 packets, KB, or milliseconds.
By default, the queue depth is set to 250ms. For most networks, this setting will lead to few
packet drops, but the queuing delay can reach 250ms in each direction. A smaller queue depth
will lead to a smaller maximum delay, but potentially more dropped packets. If possible, specify
the queue depth and units to match the queuing behavior of the WAN transmission equipment
on the network being emulated.
4.2.2 Framing Overhead
Framing overhead is the number of additional bytes required by a link-layer technology when
transmitting a packet of data. Typically, the framing overhead consists of link-layer addressing
and error checking information.
To emulate a link-layer technology with a particular framing overhead, select the value from the
drop-down list, if available, or choose Custom and enter the specific value.
To emulate the traversal of a frame over a link, the Linktropy WAN Emulator calculates the
effective size of the frame as the data portion of the Ethernet frame (without the Ethernet header
or FCS) plus the specified framing overhead.
The Linktropy WAN Emulator includes three choices for framing overhead:
Ethernet (header + FCS)
This option emulates a WAN link layer with an Ethernet-like frame of 18 bytes of header and
frame check sequence (FCS). This is the default option and is a reasonable choice if the
properties of the link layer are unknown.
Ethernet (header, FCS, preamble, pad)
This option emulates an actual Ethernet link, including the preamble and padding between
Ethernet frames. Select this option to emulate an Ethernet-based WAN network.
Custom
This option allows the specification of any link layer framing overhead in bytes per data
packet up to a maximum of 300 bytes. Select this option if the link layer framing overhead is
known.

5BRIDGE/ROUTE TAB:
BRIDGE AND ROUTING MODE CONFIGURATION
The Linktropy WAN emulator can be installed as either a bridge or router to forward frames
between the LAN A and LAN B Ethernet interfaces. By default, the Linktropy WAN emulator is
configured as a bridge, and this mode is recommended for simplicity unless the LAN A and LAN B
interfaces need to be on separate subnets.
To switch to IP Routing Mode from Bridging Mode, click on the link switch to IP Routing Mode. To
revert to Bridging Mode, click on the link switch to Bridging Mode.
Bridge/Route settings are not stored with emulation parameters and will not change when a
stored emulation is loaded.
5.1 Bridging Mode
In Bridging Mode, the Linktropy device functions as a bridge between the Ethernet segments
connected to the LAN A and LAN B ports. In this mode, it can forward any Ethernet-based frame
regardless of network layer protocol. VLAN tagged frames (IEEE 802.1Q) are supported, but no
special action is taken based on VLAN.
Figure 6: Bridging Mode
SECTION 5BRIDGE/ROUTE TAB:
BRIDGE AND ROUTING MODE CONFIGURATION 19