CWDM, Gigabit Pluggable Transceivers and OADM

1
CWDM, Gigabit Pluggable Transceivers and OADM
Ðorde Vulovic University of Belgrade djordjev_at_rcub
.bg.ac.yu
2
CWDM

• Stands for Coarse Wave Division Multiplexing
• Form of WDM with fewer wavelengths, and with
  wider spacing between the wavelengths (compared
  to DWDM)
• The cost of the CWDM equipment is significantly
  lower than DWDM due to
• Greater spectral width and thermal drift allowed
  for lasers
• Uncooled laser technology requires less power,
  and, therefore, easier packaging
• Less films needed for mulitplexer/demultimplexer

3
CWDM DWDM Comparison
4
CWDM Standards

• ITU-T G.694.2 Spectral grids for WDM
  applications CWDM wavelength grid
• Defines 18 center wavelengths (from 1271 nm to
  1611 nm)
• 20 nm wavelength spacing
• ITU-T G.695 Optical interfaces for coarse
  wavelength division multiplexing applications
• Physical parameters for 4-channel, 8-channel and
  16-channel operation
• Aggregate Output
• Optical Path
• Aggregate Input
• Nomenclature of the CWDM systems
• CnWx-ytz (unidirectional)
• B-CnWx-ytz (bidirectional)

5
CWDM Devices

• Product range
• Optical Multiplexer/Demultiplexer
• CWDM Transceivers (GBIC, SFP)
• Optical Add-Drop Multiplexer (OADM)
• Features/Parameters to look at
• Insertion loss for the Mux/Demux/OADM
• Transmit Power/Min Receive Power/Link Budget for
  the Transceivers
• Type of connectors (SC, LC)
• Existence of the monitor port

6
CWDM Devices Cisco

• Two-module chassis (CWDM-CHASSIS-2)
• Old Modules (EOS from March 27)
• 4-Channel Multiplexer/Demultiplexer Module
  (CWDM-MUX-4)
• 8-Channel Multiplexer/Demultiplexer Module
  (CWDM-MUX-8)
• Add-Drop Module (CWDM-MUX-AD-1470,1490,1510,1530,
  1550,1570,1590,1610)
• New Modules
• 8-Channel Multiplexer/Demultiplexer Module
  (CWDM-MUX-8A)
• 4-Channel Single Fiber Multiplexer/Demultiplexer
  Module (CWDM-MUX-4-SF1,2)
• 4-Channel Add-Drop Module (CWDM-OADM4-1,2)
• Single Wavelength Dual Channel Add-Drop Module
  (CWDM-OADM1-1470,1490,1510,1530,1550,1570,1590,16
  10)

7
CWDM Devices Cisco (contd)
4-Channel Single Fiber Multiplexer/Demultiplexer
Module
Single Wavelength Dual Channel Add-Drop Module
4-Channel Add-Drop Module
8-Channel Multiplexer/Demultiplexer Module
8
CWDM Devices Finisar

• Standalone (Optibox) or rack-mountable
  (Plugin)
• Products
• 4-Channel Multiplexer/Demultiplexer
  (MUX-DEMUX-4-P-SC,LC)
• 8-Channel Multiplexer/Demultiplexer
  (MUX-DEMUX-8-P-SC,LC)
• Single Wavelength Dual Channel Add-Drop Module
  (FSW-OADM1-47,49,51,53,55,57,59,61)
• 4-Channel Add-Drop Module (FWS-OADM-4-1,2)

9
CWDM Applications Point-to-Point
10
CWDM Applications Bus
11
CWDM Applications Protected Hub-and-Spoke
Primary link
Backup link
12
CWDM Applications Ring
Primary link
Backup link
13
Gigabit Pluggable Transceivers

• Gigabit Ethernet ports usually come in the form
  of the placeholder for the transceiver
• Two types of transceivers
• GBIC GigaBit Interface Converter
• SFP Small Form-factor Pluggable
• Plug-and-play, hot-swappable

14
GBIC

• Originally made for Fiber Channel nowadays most
  popular for Gigabit Ethernet
• Standardized by the SFF committee
  (http//www.sffcommittee.org).
• Current specification v5.5 (document SFF-8053)
• Most GBICs support line rate around 1 Gbps
• Line rate for 1xFC 1.0625 Gbps
• Line rate for Gigabit Ethernet 1.25 Gbps
• There are GBICs for 2xFC (line rate 2.125 Gbps)
• Host interface SCA-2 (20-pin)
• Network interface
• DSC (1000BASE-SX, 1000BASE-LX, 1000BASE-LX, CWDM)
• RJ-45 (1000BASE-T)
• etc.

15
GBIC EEPROM

• EEPROM which contains fields as
• Type of serial transceiver (GBIC, SFP etc.)
• Connector (SC, LC, MT-RJ etc.)
• Code for electronic and optical compatibility
  (1000BASE-SX, 1000BASE-LX etc.)
• Link length supported for 9/125 µm fiber, in km
• Link length supported for 9/125 µm fiber, in 100m
  units
• Link length supported for 50/125 µm fiber, in 10m
  units
• Link length supported for 62,5/125 µm fiber, in
  10m units
• Vendor name
• Vendor OUI
• Specified in the Annex D of the GBIC
  specification

16
GBIC EEPROM (contd)

• cisco3550pwrsh controllers ethernet-controller
  gi0/1 phy
• General GBIC Registers
• Identifier 01
• Connector 00
• Transceiver 00 00 00 08 00
  00 00 00
• Encoding 01
• BR_Nominal 00
• Vendor Name CISCO_at_SYSTEMS
• Vendor Part Number WS-G5483
• Vendor Revision 20 20 20 20
• Vendor Serial Number FHH0749T0MK

0x01GBIC
0x00Unspecified (er)
0x081000BASE-T
17
GBIC Compatibility

• A GBIC from any vendor in a device from any
  vendor unfortunately NO
• Even though the GBICs comply with the same
  standard
• Moreover, major equipment vendors do not
  manufacture GBIC they sell it as an OEM product
  (so vendor X switch may not use vendor Y GBIC
  although it may be exactly the same as the vendor
  X GBIC)
• If the GBIC has EEPROM, device can read e.g. the
  Vendor ID and block the port if a foreign GBIC
  is found
• Cisco, Extreme, 3Com etc.
• Cisco GBICs have security code which is
  recomputed by the switch if they differ, port
  will be put in the err-disabled state

18
SFP

• Created as an effort to achieve greater port
  density
• GBIC width 3 cm
• SFP width 13 mm (similar to RJ-45 jack width)
• Other new features
• SONET application
• 4xFiber Channel application (4 Gbps)
• Transceiver Diagnostic
• Standardized by the SFF committee (current
  specification SFF-8074)
• Network interface
• LC (1000BASE-SX, 1000BASE-LX, 1000BASE-LX, CWDM)
• etc.

19
SFP Diagnostics

• Host can read in real-time the following
  parameters
• Internally measured transceiver temperature
• Internally measured transceiver supplied voltage
• Measured TX bias current
• Measured TX output power
• Measured RX received optical power
• Two more parameters can be added in the future
• Specified in the SFF-8472
• Some newer GBICs have adopted this feature
• e.g. Cisco DWDM GBICs (Cisco calls this feature
  DOM Digital Optical Monitoring)

20
SFP Diagnostics (contd)

• CVT-Bratislavash inte tra
• If device is externally calibrated, only
  calibrated values are printed.
• high alarm, high warning, - low
  warning, -- low alarm.
• NA or N/A not applicable, Tx transmit, Rx
  receive.
• mA milliamperes, dBm decibels (milliwatts).
• Optical
  Optical
• Temperature Voltage Current Tx Power
  Rx Power
• Port (Celsius) (Volts) (mA) (dBm)
  (dBm)
• ------- ----------- ------- -------- --------
  --------
• Gi3/3 50.5 3.30 36.1 2.9
  0.6
• Gi3/9 54.0 3.29 54.0 2.8
  3.3
• Gi3/10 51.6 3.30 40.2 2.9
  3.7
• Gi4/6 50.7 3.30 44.6 2.9
  1.6
• Gi4/12 41.1 3.30 36.3 2.8
  -0.8