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A Glimpse Into The Future: 25G & 50G Ethernet

2017-11-24 10:54:55 | Transceiver

With the ever growing usage of 10G network, 10G could not satisfy the requirement for some Ethernet network users who urge for a higher demand on speed, distance, media and cost. Under this circumstance, upgrading network is paramount. For 100G network upgrading, there are three available approaches, “10G—40G—100G”, “10G—25G—100G” or “10G—25G—50G—100G”. The latter two are announced to better satisfy the data center and cloud network. Comparing to 40G and 100G, people heard less about 25G and 50G. So what are they? This article would put emphasis on 25G Ethernet and 50G Ethernet as well as their optics.

25G-100G immigration

 

25G Ethernet

25 Gigabit Ethernet, abbreviating as 25G Ethernet, is standard for Ethernet network connectivity. Developed by IEEE P802.3by 25 Gb/s Ethernet Task Force, 25G Ethernet is a standard for Ethernet connectivity. The 25 Gigabit Ethernet Consortium is an open organization to all third parties who wish to participate as members to enable the transmission of Ethernet frames at 25 or 50 Gigabit per second (Gbps) and to promote the standardization and improvement of the interfaces for applicable products. The main features of 25G Ethernet are listed in the following:

  • A single lane per physical port maximizes the number of connected servers or uplinks per switch.
  • Single higher speed 25 Gb/s lanes maximize bandwidth and switch fabric utilization vs. 4 x 10 Gb/s lanes.
  • Overall higher port count, utilization and total server interconnect bandwidth vs. 40 GE.
  • Connections to switch ASICs is limited by SERDES count and bandwidth.
SFP28 Pluggable Modules

SFP28 is the abbreviation of Small Form-Factor Pluggable 28, which is the third generation of SFP interconnect systems. The SFP28 optical module is designed for 25G performance and developed by the IEEE 802.3by specification. According to the SFP28 Multi-Source Agreement (MSA) and SFP28 specification, the SFP28 is designed with a form factor, optical/electrical connection and digital diagnostic interface. In addition, the SFP28 optical transceiver has also been designed to meet the harshest external operating conditions including temperature, humidity and EMI interference. Below are the industry standard 25G optics:

industry standard 25G optics

50G Ethernet

Comparing to 40G Ethernet, 50G Ethernet is more rarely known by people. Being led by the 25G Ethernet Consortium, 50G Ethernet is initially based on 2 lanes of 25 Gb/s. IEEE802.3bs is the 50G per lane specifications to support Nx50G configurations. And the standard expected in September 2018 while the interface expected on the market in 2018+. Different from 40G Ethernet, 50G initial limited deployment as proprietary 2x25G. In terms of technology, 40G and 50G per lane (Serial) technology will be defined together (40G as reduced speed 50G). With the respect of cost, 40G and 50G Serial will have similar cost, i.e. 50G Serial will offer 25% more bandwidth for the same cost. The core features of 50G Ethernet are listed in the below:

  • A faster base signaling rate is needed to for higher capacity.
  • Similar to 25 GE, 50 GE extends existing common network topology for higher speed.
  • The server and data center market requirements vary widely.
50G Pluggable Modules

New 50 GE pluggable modules are in the same common form factor sizes as other common pluggable modules. There are two form factors of 50G modules, SFP56 and QSFP56. The SFP56 pluggable module has the same size as SFP, SFP+ and SFP28 while the QSFP56 pluggable module has the same size as QSFP, QSFP+ and QSFP28.

Conclusion

Through this article, we are cleared the 25G and 50G Ethernet as well as their optics respectively. With the ever increasing usage of network data due to millions of new connected devices to servers and storages data centers, 25G Ethernet and 50G Ethernet provide a flexibility, scalibilty, cost-efficient way for adapting to future network growth.

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10G Technology: 10GBASE-T Vs. SFP+

2017-11-09 10:34:40 | Transceiver

As the basis of upgrading network, 10G network has been ubiquitous in data center, enterprise network and even home networking. 10GBASE-T and 10G SFP+ are two different kinds of technology which transmit data via copper and fiber respectively. 10GBASE-T technology provides the most flexible and economical solution while 10G SFP+ offers the compatible and user-friendly solution for 10G Ethernet connectivity option. This article would shed light on the difference between 10GBASE-T and 10G SFP+.

10GBASE-T Technology

As the fourth generation of IEEE standardized Base-T technologies, 10GBASE-T is designed to reduce overall costs and improve flexibility. By using RJ45 connectors and unshielded twisted pair cabling, 10GBASE-T allows 10Mbps, 100Mbps, 1Gbps, and 10Gbps data transmission, while being backward-compatible with prior generations. Merits and demerits of using 10GBASE-T are listed in the below.

Pros of 10GBASE-T
  • Cheap twisted pair cables.
  • Patch panels can be used without messing around with transceivers.
Cons of 10GBASE-T
  • Higher power consumption.
  • People may get tempted to use substandard cabling, and this would have a negative influence on the speed.
  • No good way to extend length beyond 100m (though this can be somewhat mitigated by choosing switches with mostly 10GBASE-T but also a handful of SFP+ ports) limited choice of equipment.
10G SFP+ Technology

The 10G SFP+ transceiver meets the standard of Multi-Sourcing Agreement (MSA), and provides the cost effective solution for 10G optical data communication. It supports both duplex and simplex LC optics interfaces. The 10G SFP+ transceiver consists of 10Gbit/s DFB/EML optical transmitter and PIN receiver, which allow 300m~120km 10G Ethernet and 10G fiber channel applications. Advantages and disadvantages of using 10G SFP+ transceivers are listed in the below.

Pros of SFP+
  • Lower latency
  • Lower power consumption
  • Cheaper NICs and switches
  • More choice of connected equipment.
  • With transceivers and fiber basically any run length can be covered.
Cons of SFP+
  • Apparently, it is not a big deal for transmission within short distance.
  • For longer runs or runs that need to go through patch panels needs transceivers and fiber. Fiber itself is cheap but transceivers, termination, patch panels, and etc for fiber would cost a lot.
10GBASE-T Vs. SFP+

This passage would mainly demonstrate the difference between 10GbE base T and SFP+ options from the respective of technology, latency, and power consumption.

—Technology

Generally, 10GBase-T is cheaper and easier to deploy than the alternative SFP+ technologies. You can further compare these two different technologies in the following table:

Table1 Comparison between 10GBASE T and SFP Plus

—Latency

Low latency is paramount to ensure fast response time and reduce CPU idle cycles. That increases data center efficiency and ROI. With the increasing of using private cloud applications, the need for low latency is growing fast in large scale data centers.

When it comes to 10GBase-T, the PHY standard uses block encoding to transport data across the cable without errors. The standard specifies 2.6 microseconds for the transmit-receive pair, and the size of the block requires that latency to be less that 2 microseconds. SFP+ uses simplified electronics without encoding, and typical latency is around 300 nanoseconds (ns) per link. You can further compare them in the below table.

latency comparison

Basically, there are only slight differences between 10GBASE-T and SFP+ in terms of application latency. Relatively speaking, 10G SFP+ has lower latency than 10GBASE-T. High latency would exert negative influence on CPU and therefore limiting data center efficiency and increasing operational costs.

—Power Consumption

10GBase-T components today require anywhere from 2 to 5 watts per port at each end of the cable (depending on the distance of the cable) while SFP+ requires approximately 0.7 watt (regardless of distance). The difference is clearly shown in the below chart.

power consumption comparison

(Resource: http://www.datacenterknowledge.com)

Conclusion

Through this article, we are clear about the pros and cons of 10GBASE-T and SFP+ as well as their differences in technology, application latency and power consumption. It is evident that SFP+ is the right technology to ensure optimal performance with lowest latency and lower power usage in the data center. The cost saving becomes obvious when deploying from 1000 to 10,000 cables in the data center.

Originally published at http://www.fiber-optic-cable-sale.com/10g-technology-10gbase-t-technology-vs-sfp-plus-technology.html.

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Stacking Vs. Chassis Switch: How to Choose?

2017-11-03 10:38:13 | Switch

Maximizing scalability and optimizing performance are two paramount factors when you design or upgrade your network. It is hard to find the right balance. Given that you need more than 48 ports in a wiring closet, but you could not decide which type of switches to buy. Stacking switch or non-stacking switch? Or does a modular chassis solution make more sense? In this article, we would make a comparison between stacking and chassis access switches and guide you to make an appropriate decision.

Stacking Switches Solutions

Over the years, stacking network switches have been highly favored by lots of Ethernet users and been a core component of an enterprise-grade switch. So what is reason for the popularity of stacking switches? By using stacking switches, we can add ports as we need them by simply purchasing another switch and adding it to the stack. We can stack up to nine Cisco 3750-X switches and have 432 x 10/100/1000 ports and 18 x 10 Gbps ports. We can do this using only 9RU's of rack space. A chassis would require over double the rack space to achieve this access port density. This makes these switches very popular as top-of-rack switches in the data center.

brocad-stackable-switches

Figure1: Brocade Stackable Switches

Pros of Stacking Switches
  • Pay-as-you-grow
  • Small Physical Footprint
  • Convenient 100v Power Standard
  • Virtual Chassis Capability
  • Cross-Stack EtherChannel
Cons of Stacking Switches
  • Management Difficulties
  • Power Demands
  • Software Complexity
  • Instability
Chassis Switches Solutions

Chassis devices, often being "premier" devices, may offer software and/or hardware features unavailable on a stack. They are the flagship models of every vendor's switching line. In contrast to the fixed configuration switches, it is engineered to operate as single integrated system. Configuring high availability is simple and it works every single time. A failed line card will not bring down the entire chassis. Additionally, a chassis will drive consistency in deployment.

Cisco Chassis Switches

Figure2: Cisco Chassis Switches

Pros of Stacking Switches
  • Solid High Availability Features
  • Modular Design
  • Supports Wide Range of Line Cards
  • Simple to Deploy
Cons of Stacking Switches
  • Physical Space (twice the space of stacks)
  • Expensive Power Supplies
  • 220v Power for PoE Solutions
How to Choose?

Just as the same as the every comparison on the similar kits, the decision really depends on your actual requirements. Once we have this, finding the right hardware is very straightforward. It is important to balance the cost of acquisition versus the cost of operations and impact to the business due to outages. And that is what we always thinking about when we make a decision.

In this article, we mainly provide the detailed information about stacking and chassis switches solutions, and offer you relatively enough information to help you to make a decision on choosing the best switching solutions for setting up or upgrading your network. There are too many variables to give a one-size-fits-all recommendation, but in general chassis Ethernet switches' solutions are our preference. In addition, you should keep in mind that pricing should not be the focused too much. We can get both designs for a pretty reasonable price, regardless of requirements. If your network can benefit from both stackables and chassis, the chassis solution would be a good choice.

Originally published at http://www.fiber-optic-cable-sale.com/stacking-vs-chassis-switch-how-to-choose.html.

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