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Copper-to-Optical Aggregator nTAP Installation – viavidoc.com/observerstart
Copper-to-Optical Aggregator nTAP InstallationRelated information
Features
Key features of the Copper-to-Optical Aggregator nTAP include:
♦ Passive access without packet tampering or introducing asingle point of failure
♦ All traffic (including errors) is passed from all OSI layers foranalyzing
♦ Enhanced security because the nTAP does not require or usean IP address, making it undetectable compared to a SPAN
♦ Allows you to connect and disconnect the analysis device asneeded without taking the network down
♦ Fully IEEE 802.3 compliant
♦ Fully RoHS compliant
♦ Automatic link failover for devices that have an alternatepath
♦ Optional redundant power ensures maximum monitoringuptime
♦ LEDs show power and link status
♦ Front-mounted connectors make installation simple
♦ Optional 19-inch 1U rack mount panel holds up to three nTAP
PartsThe Copper-to-Optical Aggregator nTAP comes with several parts.If any part is missing or damaged, contact VIAVI immediately.
The Copper-to-Optical Aggregator nTAP ships with the followingitems:
♦ Copper-to-Optical Aggregator nTAP
♦ Quick Reference Card
♦ A/C power cord
♦ Voltage auto-sensing universal power supply
Your kit may also contain optionally available parts (for instance,patch cables).
Installing
Prerequisite(s):
♦ Decide where to place the nTAP and physically mount it, ifdesired. Depending on the form factor purchased, this maybe in a drive bay, rack mount bracket, or wherever it is mostconvenient.
♦ Keep the nTAP horizontal for efficient heat dissipation.
♦ The network adapter you connect to the Analyzer side ofthe Copper-to-Optical Aggregator nTAP must have auto-negotiation disabled, otherwise no traffic will be passed tothat network adapter. This also means the network adaptermust support the ability to disable auto-negotiation; notall third-party network adapters support this. However,all Gen3 capture card models can enable and disable auto-negotiation.
A Conversion Aggregator TAP is used when the analyzercommunicates over a different topology than the network (coppervs. optical). It merges full-duplex links into a single stream fortransmission to the analyzer ports. The TAP receives a full-duplexsignal and sends it out as a half duplex signal. The Link andAnalyzer sides negotiate their connections independently so thateach is optimized. The Link (network) side's signal may be thesame speed or slower than the Analyzer side; it cannot be faster.
This is true whether you use copper or optical connections forthe Analyzer ports. For instance, if your Link side is at 100 Mband your analyzer connection is 1 Gb, the TAP sends data to theanalyzer at 1 Gb, known as up-converting, and there is no chanceof over-subscribing the buffer. If your Link side is 1 Gb, then yourconnection to the analyzer must also be 1 Gb. It cannot be 100 Mbbecause the analyzer cannot receive the traffic from the Link sidefast enough.
When traffic comes in to Link A, two copies are made in the TAP.One copy is sent out Link B to the switch and the other copy isjoined with a copy of the traffic from Link B and sent out theAnalyzer AB ports to the analysis device(s). A similar thing happenswith traffic that comes in Link B. Two copies are made. Due tohow the TAP is designed, it is not possible for traffic from theAnalyzer side to pass to the Link side.
Caution: Before you temporarily break the linkbetween the device of interest and the network, you
© 2018 Viavi Solutions (2 Jul 2018)
may want to shut down access to that device andnotify users of the down time.
1. Ensure that power is connected to the nTAP. You can providepower to one or both power supply sockets on the backpanel of each nTAP. Connecting both sockets to differentexternal power sources provides fail-safe power redundancyfor the Analyzer side.
2. Disconnect the cable from your device (typically a switch)and connect it to Link B. You want to connect Link B firstbecause it negotiates its network speed first, and Link Athen must use the same speed as Link B. If your link is partof a failover or redundancy arrangement, then connect thefailover device to Link B.
3. Connect your network device (or primary device in a failoverarrangement) to Link A.
4. Connect the Analyzer ports on the TAP to the receiving portsof the monitoring device.
Note: The role of the buffer is to absorb traffic spikesof over 50% full-duplex bandwidth saturation (100%with both sides combined), because the analyzer’ssingle-receive interface cannot receive the trafficfast enough to keep up at line rate. For more detailsabout the Aggregator TAP’s buffer, see Choosing theAggregator TAP buffer size.
Choose either copper or optical cables to connect to youranalyzer. If an SFP is present, its corresponding copper Analyzerport is disabled. The optical ports only support a 1 Gb networkconnection.
All Optical TAP devices contribute to optical attenuation. See afuller discussion of it in Attenuation.
When turned on, the TAP performs a sequence of steps todetermine whether its link ports are connected to any devices,and what speeds and other capabilities those devices have. Theblinking pattern of the LEDs indicate which step of the connectionprocess the TAP is performing. The duration of each state dependson the type of equipment attached to each port of the TAP. Hereare the connection steps, listed in the order they occur:
1. Capabilities search. Both link ports/connections on theTAP are attempting to attach to their respective devices anddetermine a common speed and other capabilities. The LEDpattern is that the Speed LEDs flash (slower) and the LinkLEDs flicker (faster).
2. Connecting. The link parameters are attempting to connectusing the parameters determined during the capabilitiessearch. The LED pattern is that the TAP shows the connectionspeed while the Link LEDs continue to flicker.
3. Connected. Both link ports/connections are connected tothe link partners at a common speed. The Speed LED showsconnection speed. The Link LEDs light steadily (idle) or flickerdepending on whether there is any traffic present. If a LinkLED is unlit, there is no functioning device connected to thatport.
When the Copper-to-Optical Aggregator nTAP experiences powerloss, the following occurs:
♦ If you are using a redundant power supply or the TAPis attached to an uninterruptible power supply (UPS), itprovides power with no loss of network connection.
♦ If you are not using a redundant power supply or UPS, orpower to both power supplies is lost, then:
● The Analyzer ports stop working and the analysisdevice(s) connected to the TAP will go “dark.”
● The TAP continues to pass data between the networkdevices connected to it (firewall/router/switch toserver/switch). In this sense the TAP is passive.
● The network devices connected to the TAP on the Linkports must renegotiate a connection with each otherbecause the TAP has dropped out. This may take a fewseconds.
Error conditions are shown by the LEDs for approximately 10seconds, after which the TAP resets itself (goes back to theCapabilities connection step).
LED Pattern Error Condition
The LEDsrepeat thesequence:10> 100>1000.
No Common Speed. There is no commonspeed capability between the devicesattached to Link A and Link B.
Memory Failure (aggregator nTAP only). Thesoftware failed to initialize the aggregationbuffer.
The 10 LEDflashes. Theother SpeedLEDs are onand do notflash.
Timed Out. The TAP software has timed outwaiting for some event.
Theexpectedspeed’s LEDis on, whilethe actualspeed’s LEDflashes.
Wrong Speed. One of the links has connectedat the wrong speed.
The 1000LED flashes.The otherSpeed LEDsare on anddo not flash.
Logic Error. This error occurs when the linkpartner capabilities are ambiguous.
FAQ – viavidoc.com/observerstart
FAQProduct dimensions, weight, power consumption, installedoperating system, RAM and details along with photos of theappliance.
Technical specificationsThis section lists the dimensions, power requirements, supportedmedia, and environmental requirements.
Both power connectors are located on the back panel, along withthe model information and serial number.
Power requirements
AC Input 100-240V 50/60Hz 0.5A
OperationalVoltage
5V (+10%/-5%, < 100 mV ripple)
OperationalCurrent
Typical: <= 1.8 amps; Max: <= 2.8 amps
PowerDissipation
Typical: 8 watt; Max: 14 watt
Environmental requirements
Temperaturerange
32°F - 113°F / 0°C - 45°C (operating): Thefanless cooling design relies on conductionand convection from the nTAP casing. Yourinstallation environment must provideenough cool airflow for the nTAP casing tomaintain an operating temperature less than113°F/45°C.
-52° to +185°F / -47° to +85°C (storage)
Humidity 35-85% (non-condensing)
Supported media
Link ports Straight-through RJ-45 cable or crossovercable
CopperAnalyzerports
Straight-through RJ-45 cable or crossovercable
SFP/XFPAnalyzerports
1000BaseSX, 850nm, Multimode, LCConnector; 62.5 or 50 µm fiber
1000BaseLX, 1310nm, Multimode or Single-mode, LC Connector; 62.5, 50, or 8.3 µm fiber
Wavelength tolerance ranges
Multimode850/1300(Dual-window)
+/- 20 nanometers
Single-mode 1310 or1550 (Dual-window)
+/- 40 nanometers
Buffer size 256 MB, 512 MB, or 1 GB (depending on TAP)
Dimensions
Width 5.62 in/14.28 cm
Height 1.15 in/2.93 cm
Length 7.79 in/19.78 cm
What latency does a TAP create?Latency is created by the copper ports of a TAP. The latency istypically 200-250 nanoseconds. This is the time it takes to receivea packet, process and copy it, and begin forwarding the copy. Theoptical portion does not introduce any latency.
Are the analyzer ports “send only”?Yes, the analyzer ports are send only. The TAP is incapable ofsending data from the Analyzer side of the TAP to the Link (ornetwork) side of the TAP.
The “A,” “B,” or “AB” ports on the Analyzer side of the TAP mustbe capable of both transmitting and receiving data to negotiatea connection with the analyzer and they do this through thephysical interface. The physical interface is responsible fornegotiating a bi-directional connection with the analyzer andunidirectionally sending data from the TAP to the analyzer.
There is no physical connection between the receive port onthe Analyzer side of the TAP and the TAP’s internal processor.Therefore, the TAP cannot transmit data from the analyzer back tothe Link side of the TAP.
This image shows the data flow for the High Density OpticalTAP. In it you can see a Y-cable is used to connect the TAP to theAnalyzer. Notice that only the RX side of the LC connectors in theAnalyzer have a physical cable. The TX side of the LC connectors inthe Analyzer—even if there is a cable present—cannot send datato the TAP.
All TAPs that have an optical connection to the Analyzer use theY-cable. This includes the pure optical TAPs, Copper-to-OpticalConversion, and Copper-to-Optical Aggregator. Instead of a Y-cable two single TX-to-RX connectors could be used. The TX side isinserted into the TAP and the RX into the Analyzer.
© 2018 Viavi Solutions (2 Jul 2018)
Not seeing traffic at the analyzer from theTAPIf your TAP is not transmitting to the analyzer as you expect,check the following:
♦ The Link is definitely up and running.
♦ The cable connected to the analyzer functions properly. Use adifferent cable to confirm this.
♦ The Ethernet/SPAN or Fiber channel is not divertedelsewhere.
♦ Try swapping the cables between the ports.
♦ The nTAP is receiving power using a VIAVI power adapter. TheLink A and Link B lights flash when there is traffic traversingthrough the nTAP, which indicates the nTAP has power.
♦ Use a light meter to verify there is enough light power forany optical links.
♦ The correct SFPs are used.
♦ If you are using an optical connection from the nTAP toyour analyzer, including a GigaStor, ensure that the receiveNIC on the analyzer has auto-negotiation disabled. If auto-negotiation on the NIC is enabled, you will not be able to seetraffic from the nTAP. If this network adapter does not havethe option to disable auto-negotiation, you must obtain adifferent network adapter that can—there are no exceptions.
♦ If the system you are monitoring is Linux or UNIX based, youmay have an issue with the Maximum Transmission Unit size.The TCP stack in the UNIX system uses algorithms to producean MTU based on response time from SYN ACK. A small MTUforces a server and client to redo their handshake. Increasethe MTU on your server to alleviate this issue.
Can I daisy chain an Aggregator TAP?Yes, you can daisy chain TAPs, but it is not recommended becauseof the negotiation time and latency introduced by the TAP.Although the latency is very small, if the packets do not reachtheir destination fast enough and the receiving device has a lowMTU (maximum transmission unit), the receiving device couldrestart the negotiation process. For more details, see Not seeingtraffic at the analyzer from the TAP (page 4).
If you experience issues daisy chaining Aggregator TAPs to morethan two analyzers, and you are certain your MTU on the receivingdevices is high enough, contact VIAVI Support for assistance.
How do I connect my failover devices?When the device connected to Link B fails, the TAP disables Link Aso that the device on Link A can initiate its failover procedure.
The TAP then restarts its search phase. Until the Link B device isworking again, the TAP repeats the following steps:
1. Search.
2. Determine if Link A is up. If not, keep searching.
3. If Link B is up, then re-establish the connection. If Link B isstill down, then shut down Link A.
4. Go to first step.
This figure is for illustrative purposes and may not match yourproduct.
Managing attenuationManaging signal attenuation is critical for running a network atoptimal performance.
If signal attenuation is too high, destination devices may notbe able to establish a link or receive network traffic. Repeaterscan help, but they can be costly and inconvenient to implement.In general, unless a signal must travel a long distance or iscompromised by patch panels, there should not be a problemusing the 50/50 split ratio. The most efficient and cost-consciousway to manage attenuation is to measure signal levels throughoutthe network and place repeaters only when and where they areneeded.
To determine if a light signal is at an acceptable level at anypoint on a network, it is helpful to use an optical power meter.Optical power meters measure signal power at a port, helpingyou determine whether a device is receiving a strong enoughsignal and thereby identifying if repeaters need to be placed. Themeters are typically inexpensive and are offered from a number ofvendors.
MemoryFully optical TAPs do not have internal memory or any electroniccomponents and are strictly a pass-through wherein a copy of thedata is made. TAPs with any copper connections have two distinctand separate memory stores.
The two memory stores are non-volatile memory and volatilememory. They are not connected in any way and no data canmove between them. The non-volatile memory provides certainfunctions that make the device work and cannot be modified orchanged during normal operation of the device. Volatile memoryholds network data as it is copied and passed through the device.Turning off the device clears any data in the volatile memorybuffer.
Technical Support
NorthAmerica
1.844.GO VIAVI / 1.844.468.4284
LatinAmerica
+52 55 5543 6644
EMEA +49 7121 862273
APAC +1 512 201 6534
All OtherRegions
viavisolutions.com/contacts
email [email protected]
Support hours are 7:00 A.M to 7:00 P.M. (local time foreach office).
