Tag Archives: 10G BiDi SFP+

How to Light a DWDM Ring Beyond 10G?

Network layout nowadays is no longer limited by old rules created for early Ethernet networks. The technology and infrastructure devices available currently allows for different network topologies, including bus, star, ring and mesh networks. Each of them has its benefits and drawbacks and can be combined to suit application needs. This article emphasizes on the DWDM ring network configuration, illustrating the approaches to build a fiber ring beyond 10G.

What Is a DWDM Fiber Ring?

A fiber ring refers to the network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node. A ring configuration is designed to withstand a single failure. If there happens to be a failure, the system automatically reconfigure itself.

Similarly, a DWDM ring network includes a fiber in a ring configuration that fully interconnects nodes. Two fiber rings are even presented in some systems for network protection. This ring DWDM topology is commonly adopted in a local or a metropolitan area which can span a few tens of kilometers. Many wavelength channels and nodes may be involved in DWDM ring system. One of the nodes in the ring is a hub station where all wavelengths are sourced, terminated, and managed, connectivity with other networks takes place at this hub station. Each node and the hub have optical add-drop multiplexers (OADM) to drop off and add one or more designated wavelength channels. As the number of OADMs increases, signal loss occurs and optical amplifier is needed.

DWDM ring

How to Create a DWDM Fiber Ring Beyond 10G?

Assuming to build a higher than 10G optical ring using two strands of dark fibers, all nodes in this ring configuration are less than 10km apart and there are 8 nodes in total. Here we illustrate the options for achieving a DWDM ring beyond 10G.

20G Fiber Ring

For a 20G ring, the configuration is rather simple. There is no need for an OADM or Mux/Demux, it is recommend to use an Ethernet switch with two SFP+ ports and a pair of BIDI SFP+ optics.

Items Description
S5800-48F4S High Performance Data Center Switch (48*1GE+4*10GE)
10GBASE-BX SFP+ Generic Compatible 10GBASE-BX SFP+ 1270nm-TX/1330nm-RX 10km DOM Transceiver
10GBASE-BX SFP+ Generic Compatible 10GBASE-BX SFP+ 1330nm-TX/ 1270nm-RX 10km DOM Transceiver
40G Fiber Ring

There are three options for creating a 40G DWDM ring.

1. Use a switch with QSFP+ ports, and using QSFP+ optics in accordance. This can be the most cost-effective option for 40G if you have no future plan for more than 40G on the ring.

Items Description
S5850-48S6Q High Performance Data Center Switch (48*10GE+6*40GE)
40GBASE-LR4 Generic Compatible 40GBASE-LR4 and OTU3 QSFP+ 1310nm 10km LC Transceiver for SMF

2. Use four 10G SFP+ optics and a CWDM OADM. You could even scale up to 18 channels giving you a 180G ring if you were use all 18 CWDM channels and had that large of a OADM or Mux/Demux. First four channels with lower cost SFP+ optics, wavelength 1270nm through 1310nm. Then the next 14 channels 1350nm to 1610nm adopts SFP+ with relatively higher cost. You would need a SFP+ port per channel on both ends, and a passive CWDM OADM.

Items Description
CWDM OADM Single Fiber/ Dual Fiber CWDM OADM, East and West
10GBASE-LR SFP+ Generic Compatible 10GBASE-LR SFP+ 1310nm 10km DOM Transceiver
10GBASE-ER SFP+ Generic Compatible 10GBASE-ER SFP+ 1550nm 40km DOM Transceiver

3. Use 10G DWDM SFP+ optics and a DWDM OADM. You can choose less expensive 100Ghz optics that have up to 40 or 44 channels, or the expensive 50Ghz optics that can reach up to 80 or 88 channels.

Items Description
DWDM OADM Single Fiber/ Dual Fiber DWDM OADM, East and West
10G DWDM SFP+ Generic C40 Compatible 10G DWDM SFP+ 100GHz 1545.32nm 40km DOM Transceiver
10G DWDM SFP+ Generic H50 Compatible 10G DWDM SFP+ 50GHz 1537nm 40km DOM Transceiver
100G Fiber Ring

As for a 100G fiber ring, you can count on Ethernet switches that have 100G QSFP28 uplink ports, along with 100G QSFP28 optics. This would allow a 100G connection each way around the ring.

Items Description
S5850-48S2Q4C Carrier Grade 100G-uplink Switch (48*10GE + 2*40GE + 4*100GE)
100GBASE-LR4 Generic Compatible QSFP28 100GBASE-LR4 1310nm 10km Transceiver
Conclusion

Fiber ring enables more reliability and survivability: if a single link failure should occur – the traffic can simply be sent the other way around the ring. With the pervasiveness of Ethernet technology, the ring architecture is widely adopted to construct a Metropolitan Area Network (MAN), Metro-Ethernet service and school district that uses municipal fiber pathways. Several options for creating fiber ring beyond 10G are presented, along with the optical components needed. Hope this could be informative enough.

10G SFP+ Optics Modules and Patch Cords Selection Guide

10G connection in telecommunication network is gradually moving from the backbone to layer 2 and layer 3. Both technology and market of 10G optics modules are mature: the 10G optics modules have advanced from XENPAK which is the first generation of 10G transceiver to SFP+ which is now the most popular 10G optics. In addition, the price of 10G modules is getting lower. 10G modules are becoming affordable. Some genius guys even buy 10 SFP+ modules online to DIY private point to point 10G network. This article will offer basic information about 10G SFP+ optics modules and their connection instructions.

Basic of 10G SFP+ Optics

10G SFP+ transceiver has the same form factor of Gigabit SFP transceiver. Thus, many SFP+ modules can support 1/10G data rate to increase its flexibility during practical using. A SFP+ transceiver usually has two LC ports (as shown in the following picture). While 10G BiDi SFP+ transceiver, which transmitting and receiving signals from the same fiber optic cable, only has one LC port.

10G SFP+ transceiver and duplex patch cable

Except fiber optic transceivers, there are also various factory terminated copper-based or fiber optic based cables which are terminated with a SFP+ module on each end of the cable. There are mainly three types of these 10G cables: 10G SFP+ passive direct attached copper cable, 10G active direct attached copper cable and 10G SFP+ active optical cable. These 10G cables eliminate the used of additional patch cable and can be directly plugged into the SFP+ ports on switches. It is acceptable that these cables are an cost-effective and reliable solutions for 10G connections in short distance.

Optical Standards of 10G SFP+ Transceiver

According to IEEE standards, there are a variety 10GBASE SFP+ transceivers. For short distance transmission, 10GBASE-SR SFP+ and 10GBASE-LRM SFP+ can support transmission distance up to 300 meters and 220 meters over multimode fiber optic cables separately. 10GBASE-SR SFP+ modules is the most commonly used transceiver for short distance. It is suggested to work over wavelength of 850 nm.

There are a lot of 10G SFP+ transceivers that support long distance, like 10GBASE-LR SFP+, 10GBASE-ER SFP+, 10GBASE-ZR SFP+, CWDM SFP+, DWDM SFP+, BiDi SFP+, etc. These transceivers can support transmission distances ranging from 10 km to 120 km over single-mode fiber optic cables.

There is another special type of 10G SFP+ transceivers which has been mentioned in this post, which is known as dual-rate SFP+. For example, dual-rate 1000BASE-LX and 10GBASE-LR SFP+ transceiver can be adjusted to support both 1G and 10G data rate up to 10 km over wavelength of 1310 nm.

10G BiDi SFP+ and simplex patch cable

Fiber Patch Cable Selection Guide for 10G Transceivers

As 10G SFP+ DAC and AOC eliminate the using of additional patch cords. This part will introduce the selection guide for 10G SFP+ transceivers. During the selection of fiber optic patch cables for 10G transceivers, the transmission distance is the first element to be considered. Single-mode patch cable is used for long distance transmission and multimode is designed for short distance transmission. Then the ports on the transceiver for receiving and transmitting should be considered. As mentioned, most 10G SFP+ transceiver use duplex LC port, while BiDi SFP+ use simplex port (as shown in the above picture). Thus, simplex LC patch cords or duplex LC patch cords are used according to the port type on the transceiver. The following chart introduces detailed cabling information for 10G SFP+ transceivers.

10G SFP+ Transceivers Cabling Solution
Optical Standards Cable Type Distance
10GBASE-SR SFP+ LC duplex, MM 300 m
10GBASE-LRM SFP+ LC duplex, MM 200 m
10GBASE-LR SFP+ LC duplex, SM 10 km
10GBASE-ER SFP+ LC duplex, SM 40 km
10GBASE-ZR SFP+ LC duplex, SM 80 km
10GBASE-BX SFP+ LC simplex, SM 80 km
CWDM SFP+ LC duplex, SM 120 km
DWDM SFP+ LC duplex, SM 80 km
Dual-Rate 1000BASE-LX/10GBASE-LR LC duplex, SM 10 km
Dual-Rate 1000BASE-SX/10GBASE-SR LC duplex, MM 300 m

This post just introduced the basic information of 10G SFP+ optics and cabling information. For more specific information, please visit FS.COM, where you can find a variety of 10G SFP+ optics modules.