Keysight Technologies N4891A Getting Started
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© Keysight Technologies 2020
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Manual Part Number
N4891-90118
Edition
First edition, March 2020
Keysight Technologies Deutschland GmbH
Herrenberger Strasse 130,
71034 Böblingen, Germany
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CAUTION
A CAUTION notice denotes a hazard. It
calls attention to an operating proce-
dure, practice, or the like that, if not
correctly performed or adhered to,
could result in damage to the product
or loss of important data. Do not pro-
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A WARNING notice denotes a hazard. It
calls attention to an operating proce-
dure, practice, or the like that, if not
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Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
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Contents
Contents
1 Introduction
Safety Issues
6
Safety and damage messages
6
Safety Warnings
6
Introduction to the N4891A Solution
7
N4891A 400G Multi-Port Tester
7
N4891A 400GBASE FEC-aware Receiver Test Solution
7
Specifications
8
2 Getting Started with the N4891A Solution
Chassis Setup
10
Installing the N4891A equipment
10
Front Panel Overview
12
Controlling the Equipment
13
Connecting to the N4891A chassis
13
Configuring the Hostname
14
Setting up the N4891A solution
14
Installing License
16
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution
Getting Started Guide
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Introduction
Safety Issues
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Introduction to the N4891A Solution
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Specifications
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Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
Safety Issues
Safety and damage messages
The safety alert symbol
is used to indicate a hazard. Specific keywords and additional
graphical representations are used to explain the specific nature of each hazard. describes the safety
warning and equipment damage icons and textual conventions used in this document.
Table 1
Types of hazard
Safety Warnings
Reliable Earthing
Protective earthing connection of the socket-outlet should be verified by a SKILLED PERSON.
Touch Current from Coaxial Cables
Connect the shield coaxial cables to building earth in accordance with applicable local, national, and
international electrical codes.
Fan Instruction
Moving fan blade. Keep body parts away from fan blades.
Type of Hazard
Icon
Description
CAUTION
Indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.
WARNING
Indicates a hazardous situation that, if not avoided, could result in death or serious injury.
Additional icons are used to indicate specific types of warnings.
Laser radiation hazard warning.
Electrostatic discharge hazard warning.
High voltage hazard warning.
Hot surface hazard warning.
Moving fan blades hazard warning.
NOTICE
Indicates a condition or occurrence that could result in property damage.
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
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Introduction
1
Introduction to the N4891A Solution
N4891A 400G Multi-Port Tester
The N4891A is a compact Bit Error Rate (BER) and Forward Error Correction (FEC) test system. You
can use it to characterize and quantify, at line rate, the actual BER and FEC performance of silicon
communication devices, ASICs, fiber and copper interconnects, optical transceivers, and the port
electronics of switches, routers, and other networking equipment with 26.5625 Gbaud PAM4
interfaces. You can also use it to test the interconnection interoperability for all types of networking
devices and equipment.
It is available in two models: 2-port or 4-port. The 2-port model is field-upgradeable to 4 ports.
For both models, an optional RS-544 (KP4) FEC test capability is available that simplifies FEC lane
testing.
The N4891A is powered by IXIA's KiOS operating system, and includes Layer 1 BERT 400GE test
software. A browser-based user interface makes it easy to run tests and manage the N4891A
equipment. Keysight N4891A and Ixia A400GE-QDD offer the same capabilities and are
interchangeable.
The N4891A chassis can be mounted on a bench-top or in a rack. See “Installing the N4891A
equipment” on page 10 for more information.
N4891A 400GBASE FEC-aware Receiver Test Solution
When used in combination with the Keysight M8040A, the N4891A offers a unique 400GBASE
FEC-aware Receiver Test Solution. This solution enables measurement of frame loss ratio in 400G
Ethernet links using FEC by supplying one stressed lane, while maintaining the proper FEC striped
test pattern data. The test method is prescribed in the IEEE 802.3 standard clauses 121,122, 124 and
136, 137 and 138 (802.3bs and 802.3cd respectively). This solution provides unique insights to
understand how component and system design trade-offs are affected by Forward Error Correction
(FEC) requirements and to predict the system margin under realistic conditions.
For more information regarding the M8040A J-BERT system, refer to
https://www.keysight.com/find/M8040A.
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
Specifications
Table 2 lists out the specifications for various characteristics of the N4891A chassis.
Table 2
N4891A Specifications
Device Characteristics
Specification values
Physical Interfaces
Native QSFP-DD MSA compatible physical ports
Chassis Configurations
2- or 4-port base chassis system, desktop or rack mount, 2 RU
Chassis Connector Systems
Power ON/OFF button
1 LED per port
Clock IN / OUT: 2 SMA female connectors
Trigger IN / OUT: 2 SMA female connectors
4 USB: (2) USB 2.0 (2) USB 3.0 compatible ports
1 RJ45: 1000/100/10Mbps Ethernet management port
1 Display Port, supports a maximum resolution of 4096 x 2304 @60Hz
Chassis Clock IN – Electrical Specifications
Frequency: 166.015625 MHz +/- 100 PPM
50 ohm termination
Minimum = 0.5 Vpk-pk = 0.18 Vrms (sine)
Maximum = 3.0 Vpk-pk = 1.06 Vrms (sine)
Chassis Clock OUT – Electrical Specifications
Frequency: 166.015625 MHz +/- 100 PPM
HCSL, 50 Ohm
VOH > 0.55V, VOL < 0.15V, Swing > 0.55V
Hardware Trigger IN / OUT – Electrical
Specifications
Trigger In: 50 ohm termination; Minimum = -1.0V, Maximum = +4.0V, Swing > 0.2V
Trigger Out: HCSL, 50 ohm; VOH > 0.55V, VOL < 0.15V, Swing > 0.55V
Chassis System Electrical Power
Operates on 100-240VAC, 50/60Hz,
•
8 Amps on 100-125VAC
•
4 Amps on single phase, 200-240VAC
Chassis System Dimensions
11.14” (L) x 17.4” (W) x 3.65” (H)
283mm (L) x 442mm (W) x 92.65mm (H)
Chassis System Weights
Hardware only: 21.75 lbs. (9.87 kg)
Shipping: 30.49 lbs. (13.83 kg)
Includes rack mount ears, cable support bracket, power cord, accessories and packaging.
Temperature
Operating: 41°F to 95°F (5°C to 35°C)
Storage: 41°F to 122°F (5°C to 50°C)
Humidity
Operating: 0% to 85%, non-condensing
Storage: 0% to 85%, non-condensing
Regulatory Compliance Specifications
IEC 60950-1, UL 60950-1, CSA C22.2 No.60950-1, IEC 62368-1, UL 62368-1,
CSA 62368-1, CE (LVD, EMC, RoHS), EN/IEC 55032, EN/IEC 55024, CFR 47, FCC Part 15B, ICES-003, AS/NZ CISPR
32/24, KN32/35
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution
Getting Started Guide
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Getting Started with the
N4891A Solution
Chassis Setup
/ 10
Front Panel Overview
/ 12
Controlling the Equipment
/ 13
Installing License
/ 16
Getting Started with the N4891A Solution
10
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
Chassis Setup
The workflow to install and use a new N4891A chassis is as follows:
1
Unpack the N4891A.
2
Attach the accessories depending on how you will mount the equipment (see “Installing the
N4891A equipment” on page 10):
•
On a bench: Attach the rubber feet.
•
In a rack: Attach the mounting ears and then insert the N4891A chassis into the rack.
3
Connect the N4891A's management port to a network, and obtain an IP address.
4
Activate the license for the N4891A.
5
Connect the N4891A to the DUT.
6
Access the KiOS software and begin testing.
Installing the N4891A equipment
The N4891A chassis can be mounted on a bench or in a rack.
Bench mounting
To mount the N4891A chassis on a bench, install the four rubber feet to the bottom of the unit, one
at each corner, using the supplied screws. Refer to Figure 1.
Figure 1
Illustration for bench mounting the N4891A chassis
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
11
Getting Started with the N4891A Solution
2
Bench mounting
To mount the N4891A chassis in a rack (refer to Figure 2):
1
Install the mounting ears (one at each corner).
2
Insert the N4891A chassis into the rack and fasten the ears to the rack.
Figure 2
Illustration for bench mounting the N4891A chassis
Getting Started with the N4891A Solution
12
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
Front Panel Overview
The N4891A front panel includes the following components:
•
Power ON/OFF button
•
1 link/activity LED per port
•
Clock in/out: 2 SMA female connectors
•
Trigger in/out: 2 SMA female connectors
•
4 USB: 2 USB 2.0 + 2 USB 3.0 ports
•
1 RJ45: 1000/100/10Mbps Ethernet management port
•
1 Display Port supporting a maximum resolution of 4096 x 2304 @60Hz
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
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Getting Started with the N4891A Solution
2
Controlling the Equipment
Connecting to the N4891A chassis
The N4891A is pre-configured to obtain an IP address over DHCP. To setup N4891A and to use it for
testing, you must find the IP address assigned to it.
There are two methods you can use to find the IP address assigned to the N4891A:
•
DisplayPort: You can plug a monitor into the DisplayPort on the front panel.
•
USB flash drive: After booting and obtaining an IP address, the N4891A chassis automatically
copies its address to a USB flash drive inserted into any of the USB ports.
DisplayPort method
1
With the N4891A chassis powered off, connect one end of an Ethernet cable to the management
port of the chassis, and connect the other end to a switch port that has access to a network that
includes a DHCP server.
2
Connect a monitor to the DisplayPort on the front panel of the N4891A chassis, and a keyboard
and mouse to the USB ports.
3
Power on the N4891A chassis.
4
Use either a web browser or a console window to fetch the IP address.
•
Web Browser:
i
Launch a browser window.
ii
In the URL field, type localhost.
iii When the Landing page appears, select System Admin from the main menu (in the upper right
corner).
iv Note the IP address from the Linux OS attributes.
Figure 3
Finding IP address using the web browser
Getting Started with the N4891A Solution
14
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
•
Console window:
i
Launch a console window on the N4891A chassis.
ii
Use the ifconfig command to display the IP address.
Flash Drive method
1
With the N4891A chassis powered off, connect one end of an Ethernet cable to the management
port of the chassis, and connect the other end to a switch port that has access to a network that
includes a DHCP server.
2
Insert a thumb drive into and of the USB ports.
3
Power on the N4891A chassis.
4
Remove the flash drive and use a file explorer to find a file named hostname.txt in the root
directory of the file system on the flash drive.
5
Open the hostname.txt file and make a note of the IP address in it.
Configuring the Hostname
1
With the N4891A chassis powered off, connect one end of an Ethernet cable to the management
port of the chassis, and connect the other end to a switch port that has access to a network that
includes a DHCP server.
2
Power on the N4891A chassis.
3
Launch a terminal window to the N4891A chassis.
4
Use the following command to set the host name:
hostnamectl set-hostname
Setting up the N4891A solution
The setting up of the N4891A 400GBASE FEC-aware Receiver Test Solution requires following
additional steps:
1
Connect the ‘Clock Out’ of the N4891A chassis to the ‘Ref CLK In’ of the M8045A pattern
generator.
2
Connect the ‘Trigger Out’ of the N4891A chassis to the ‘Ctrl In A’ of the M8045A pattern
generator.
3
Connect the device under test (DUT).
i
Plug a QSFP-DD HCB Tx breakout adapter in an N4891A port.
ii
Connect lanes #2-8 of the QSFP-DD HCB Tx breakout adapter to a module compliance board
(MCB).
iii Terminate lane #1 of the QSFP-DD HCB Tx breakout adapter with a 50Ohm terminations.
4
Connect the M8045A pattern generator data out signal (from M8057A/B remote head) to the
remaining MCB lane loopback the DUT to a different N4891A port.
i
Using a compatible QSFP-DD module or cable.
ii
Using a QSFP-DD HCB Rx breakout adapter.
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
15
Getting Started with the N4891A Solution
2
Figure 4
Connection diagram sample for the N4891 solution
Getting Started with the N4891A Solution
16
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
Installing License
You must install and activate the license for the KiOS software before you can use it.
Before you begin, ensure that you:
•
know the MAC address of the N4891A chassis (you can find the MAC address on the System
Admin page)
•
have a valid license
To activate a license:
1
Ensure that you know the IP address assigned to the N4891A chassis.
2
On a PC that can access the same network as the N4891A chassis is on, open a browser window
and enter the IP address into the URL field.
The KiOS software landing page is displayed.
3
In the Settings menu, select Settings | License.
The License Manager page is displayed.
Figure 5
The License Manager page in KiOS software
4
On the License Manager page, click the MyKeysight.com link at the top of the page.
5
Login to the Keysight website, and download your license file.
6
On the License Manager page, select Add New License.
7
Select Choose File, then select the license file.
8
Select OK to add the license file to the KiOS.
NOTE
After license options are installed, the Options field in the kiOS table of the
SYSTEM ADMIN displays ‘4 Ports’ as 4P, ‘-KP4 option’ as FEC and ‘-SYC
option’ as LOKI.
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
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Getting Started with the N4891A Solution
2
Table 3 shows the fields that appear in the License Manager page along with their description.
Table 3
License Manager fields and description
License Manager field
Description
Feature
Feature enabled after installing the license.
Description
Description of the licensed feature.
Version
Version of the licensed feature.
Expiration
Date and time that the license shall expire.
Type
Type of license.
Count
Number of licenses installed.
Location
Location where license is stored.
Filename
Name of the license file.
Getting Started with the N4891A Solution
18
Keysight N4891A 400GBASE FEC-Aware Rx Test Solution Getting Started Guide
NOTE
For more information regarding the functionality and usage of the N4891A
solution, refer to the Keysight N4891A 400GBASE FEC-Aware Rx Test
Solution User Guide.
This information is subject to
change without notice.
© Keysight Technologies 2020
March 2020
www.keysight.com