Optical Interfaces Lab Last Update Copyright 2014 Kenneth M. Chipps Ph.D. 1

Objectives of This Section Learn –How to configure optical interfaces Copyright 2014 Kenneth M. Chipps Ph.D. 2

Activating Optical Interfaces In this lab we will activate two types of optical interfaces –A fiber optic cable Ethernet interface such as would be used to connect two nearby buildings to each other using singlemode or multimode fiber optic cable –A fiber optic cable ATM interface such as would be used to connect two distant buildings to each other over dark fiber Copyright 2014 Kenneth M. Chipps Ph.D. 3

Activating Optical Interfaces We will do the Ethernet interface lab in Packet Tracer The ATM interface lab will be done using Cisco 3640 routers Copyright 2014 Kenneth M. Chipps Ph.D. 4

Fiber Optic CAN Link In Packet Tracer create this network Copyright 2014 Kenneth M. Chipps Ph.D. 5

Fiber Optic CAN Link Copyright 2014 Kenneth M. Chipps Ph.D. 6

Fiber Optic CAN Link Use the 2811 for the two routers Place the NM-1FE-FX module in the 2811s in the larger left side slot –Connect the fiber ports using the orange fiber optic cable link Use the switches Use the generic host Copyright 2014 Kenneth M. Chipps Ph.D. 7

NM-1FE-FX Module The fiber optic module used in this case is the NM-1FE-FX It looks like this Copyright 2014 Kenneth M. Chipps Ph.D. 8

NM-1FE-FX Module Copyright 2014 Kenneth M. Chipps Ph.D. 9

NM-1FE-FX Module It fits in the router and connects to the fiber, either simplex or duplex, this way Copyright 2014 Kenneth M. Chipps Ph.D. 10

NM-1FE-FX Module Copyright 2014 Kenneth M. Chipps Ph.D. 11

NM-1FE-FX In general a FX module uses a 1300 nm near-infrared light source on two strands of optical fiber One for receive and one for transmit The maximum distance is two kilometers using multi-mode fiber optic fiber Copyright 2014 Kenneth M. Chipps Ph.D. 12

Fiber Optic CAN Link In the real world a link such as this would connect buildings like this Any of these four buildings could be connected Copyright 2014 Kenneth M. Chipps Ph.D. 13

Fiber Optic CAN Link Copyright 2014 Kenneth M. Chipps Ph.D. 14

Fiber Optic CAN Link Here are the commands to make this work Copyright 2014 Kenneth M. Chipps Ph.D. 15

Building on the Left –enable –config t –hostname BuildingLeft –int fa0/0 –ip address –no shutdown –int fa1/0 –ip address –no shutdown Copyright 2014 Kenneth M. Chipps Ph.D. 16

Building on the Left –exit –ip route fa1/0 –end Copyright 2014 Kenneth M. Chipps Ph.D. 17

Building on the Right –enable –config t –hostname BuildingRight –int fa0/0 –ip address –no shutdown –int fa1/0 –ip address –no shutdown Copyright 2014 Kenneth M. Chipps Ph.D. 18

Building on the Right –exit –ip route fa1/0 –end Copyright 2014 Kenneth M. Chipps Ph.D. 19

Fiber Optic CAN Link A connection over such a short distance as between any of these buildings should just work if everything is installed properly To be sure a power budget as discussed for the MAN link just below here can be computed first Copyright 2014 Kenneth M. Chipps Ph.D. 20

Fiber Optic MAN Link Let’s switch to the MAN link using the Cisco 3640 routers with an ATM OC-3 module installed For a link like this a singlemode fiber optic cable is used, which should make a connection up to 27 miles For example, we could connect the Irving campus to the Richardson location using a dark fiber link from this company Copyright 2014 Kenneth M. Chipps Ph.D. 21

Fiber Optic MAN Link Copyright 2014 Kenneth M. Chipps Ph.D. 22

Fiber Optic MAN Link Copyright 2014 Kenneth M. Chipps Ph.D Irving Location Richardson Location

Fiber Optic MAN Link At 23 miles the distance should be just within the maximum To be sure we will compute a power budget for the link With a power budget we are predicting that light reaching the receiver will be strong enough to be read correctly Here are the values for the interface card type that would be used for this link Copyright 2014 Kenneth M. Chipps Ph.D. 24

Fiber Optic MAN Link Copyright 2014 Kenneth M. Chipps Ph.D. 25

Fiber Optic MAN Link Let’s do a power budget for the proposed link If we use the Intermediate Reach card the power budget is 13 dB If we use the Long Reach card the power budget is 29 dB Copyright 2014 Kenneth M. Chipps Ph.D. 26

Fiber Optic MAN Link Here is a discussion on this from the Cisco Network Modules Hardware Installation Guide section on ATM cards The power budget - PB - is the difference between transmitter power - PT - and receiver sensitivity - PR For the Intermediate Reach card the values are –TX -15 dB and RX -28 dB Copyright 2014 Kenneth M. Chipps Ph.D. 27

Fiber Optic MAN Link –The available power budget being 13 dB –Computed in this way PB = PT – PR PB = –15 dB – (–23 dB) PB = 13 dB Copyright 2014 Kenneth M. Chipps Ph.D. 28

Link Loss Power loss - Link Loss - over a fiber-optic link arises from the following –Passive components Attenuation caused by cables, cable splices, and connectors is common to both multimode and single-mode transmission –Chromatic dispersion The signal spreads in time because of the differing speeds of the different wavelengths of light Copyright 2014 Kenneth M. Chipps Ph.D. 29

Link Loss –Modal dispersion In multimode fiber, the signal spreads over time because of the different propagation modes –Higher-order mode loss This loss results from light radiated into the fiber cladding –Clock recovery at the receiver This recovery consumes a small amount of power Copyright 2014 Kenneth M. Chipps Ph.D. 30

Link Loss The power lost over the data link is the sum of all these losses This table gives an estimate of the amount of loss attributable to each cause Copyright 2014 Kenneth M. Chipps Ph.D. 31

Link Loss Copyright 2014 Kenneth M. Chipps Ph.D. 32

Power Margin The difference between the power budget and the link loss is the power margin - PM If the power margin is zero or positive, the link should work If it is negative, the signal may not arrive with enough power to operate the receiver Copyright 2014 Kenneth M. Chipps Ph.D. 33

Power Margin For example –In this case where single-mode fiber optic cable is being used as there is a single transmission path within the fiber modal dispersion does not occur Copyright 2014 Kenneth M. Chipps Ph.D. 34

Power Margin –Here is the example they provide of this type of calculation The power budget is the output power, in this case 20 Bb, minus the loss due to the attenuation of the single over distance and the connectors in the path Two buildings 8 kilometers apart Connections through a patch panel in an intervening building with a total of 12 connectors Copyright 2014 Kenneth M. Chipps Ph.D. 35

Power Margin PM = PB – LL –= 20 dB – (8 km x (0.5 dB/km) – 12 x (0.5 dB)) –= 20 minus (4 plus 6) –=20 minus 10 –= 10 dB –A positive value means this link should have enough power for transmission –The PM in this case is 10 –The link will work as specified Copyright 2014 Kenneth M. Chipps Ph.D. 36

Fiber Optic MAN Link How about our link Will it work First the Intermediate Reach module The distance is 23 miles or 37 km PM = 13 – ((37*0,5)+(12*0.5) PM = 13 – ( ) PM = 13 – 24.5 PM = minus 11.5 Copyright 2014 Kenneth M. Chipps Ph.D. 37

Fiber Optic MAN Link That will not work How about the Long Reach version PM = 29 – ((37*0,5)+(12*0.5) PM = 29 – ( ) PM = 29 – 24.5 PM = 4.5 We must use the Long Reach version of the card Copyright 2014 Kenneth M. Chipps Ph.D. 38

Fiber Optic MAN Link Since we know it will work, let’s configure the equipment It is best to test in a lab before deploying equipment into the field So we will connect the two routes back to back Copyright 2014 Kenneth M. Chipps Ph.D. 39

Fiber Optic MAN Link For the back to back connection we will use a multimode patch cable First, we need to clean and inspect all of the connectors, patch cable, and the router interfaces Next let’s enter the configuration for each router First the Irving router Copyright 2014 Kenneth M. Chipps Ph.D. 40

Fiber Optic MAN Link enable config t hostname Irving interface atm 3/0 atm clock internal interface atm3/0.1 point-to-point ip address pvc 1/5 Copyright 2014 Kenneth M. Chipps Ph.D. 41

Fiber Optic MAN Link encapsulation aal5snap protocol ip broadcast end Copyright 2014 Kenneth M. Chipps Ph.D. 42

Fiber Optic MAN Link Now the Richardson router Copyright 2014 Kenneth M. Chipps Ph.D. 43

Fiber Optic MAN Link enable config t hostname Richardson interface atm 3/0 interface atm3/0.1 point-to-point ip address pvc 1/5 Copyright 2014 Kenneth M. Chipps Ph.D. 44

Fiber Optic MAN Link encapsulation aal5snap end Copyright 2014 Kenneth M. Chipps Ph.D. 45

Fiber Optic MAN Link Test the link by pinging between the routers from each end Copyright 2014 Kenneth M. Chipps Ph.D. 46