Category Archives: Network Solutions

What’s the Differece: 10GBASE-SR vs 1000BASE-SX

As the development of fiber optic network, there appears lots of industry standards for fiber optic transceivers. Although transceivers with different standards may have different features and performance, they sometimes can be used in the same switch port. Thus, many people may get confused by these transceivers. For example, 10GBASE-SR and 1000BASE-SX transceivers can both be inserted into the Cisco Catalyst 2960S-48TD-L switch, but the 10GBASE-SR transceiver may not work fine with the 1000BASE-SX module in another switch. Why? This post will discuss 10GBASE-SR vs 1000BASE-SX and whether 10GBASE-SR transceiver can down-support connect to 1000BASE-SX transceiver.

connect 10GBASE-SR to 1000BASE-SX

10GBASE-SR vs 1000BASE-SX

As mentioned above, 10GBASE-SR and 1000BASE-SX are two kinds of industry standards for fiber optic transceivers. This part will introduce them in turns.

10GBASE-SR

10GBASE-SR is defined in the IEEE 802.3 Clause 49 standard, specially designed for multi-mode fiber optic medium that uses 850 nm lasers. It has a data transmission rate of up to 10.3125 Gbps and can be used over multiple cabling options. But the transmission distance may differ as the fiber cable changes. For example, when used over OM1 cabling, the 10GBASE-SR has a maximum working distance of 33 meters, as opposed to 82 meters when applied over OM2 cabling. Nowadays, the 10GBASE-SR module usually applied over OM3 and OM4 cablings to give a more structured optical cabling used in large buildings. And the transmission distance respectively are 300m and 400m.

1000BASE-SX

Like 10GBASE-SR, 1000BASE-SX is also an IEEE 802.3z standard for the multi-mode fiber optic cabling. But it has a minimum transmission distance of 220m and a maximum of 550m. Offering 1Gbps data transmission rate, 1000BASE-SX modules are mainly used to connect high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs.

Can 10GBASE-SR Transceiver Down-Support Connect to 1000BASE-SX Transceiver?

10GBASE-SR modules are generally referring to 10GBASE-SR SFP+ transceivers, and 1000BASE-SX modules are usually 1000BASE-SX SFP transceivers. And since SFP+ and SFP transceivers share the same size (as shown below), SFP transceivers can often used in most SFP+ ports (For example, almost all SFP+ ports of Cisco switch can accept SFP transceivers). Then can a 10GBASE-SR SFP+ transceiver down-support connect to the 1000BASE-SX SFP transceiver?

10GBASE-SR vs 1000BASE-SX

10GBASE-SR vs 1000BASE-SX Transceivers

The answer is no. Unlike copper SFP transceivers, 10GBASE-SR SFP+ transceivers do not have such functions as auto-negotiation. In fact, both 10GBASE-SR SFP+ and 1000BASE-SX SFP transceivers can only run at the rated speed fixed by the electro-optical conversion ASIC built into the transceiver hardware. That’s to say, 10GBASE-SR SFP+ transceivers can only run at 10Gbps and 1000BASE-SX SFP transceivers run at 1Gbps. So there is no such fiber link that one end does 1G while the other end does 10G.

10GBASE-SR vs 1000BASE-SX: Have You Known the Differences?

To conclude, although 10GBASE-SR and 1000BASE-SX share something in common, they are totally different Ethernet standards for transceivers. 10GBASE-SR SFP+ transceivers mainly work in 10G links, while 1000BASE-SX transceivers can only run at 1Gbps even though in the SFP+ slot. Thus, it will not work out to connect a 10GBASE-SR SFP+ transceiver with a 1000BASE-SX SFP transceiver.

Hyperconverged Infrastructure Basics

Hyperconverged infrastructure has been talked a lot in recent years and its adoption is skyrocketing in data centers. However, many people are still confused by this term. This post will introduce it in details.

What’s Hyperconverged Infrastructure

Hyperconverged infrastructure is often named HCI. It is introduced in 2012 to describe a fully software-defined IT infrastructure that virtualizes all the elements of conventional hardware-defined systems. In other words, the networking and storage tasks in the hyperconverged infrastructure are implemented virtually through software rather than physically in hardware. Generally, hyperconverged infrastructure is at least composed of virtualized computing (a Hypervisor), a virtualized SAN (software-defined storage) and virtualized networking (Software-defined networking). It can be utilized as a way to pool together resources so as to maximize the interoperability of on-premises infrastructure.

Hyperconverged Infrastructure

Hyperconverged Infrastructure VS Converged Infrastructure

Hyperconverged infrastructure and converged infrastructure are two alternative solutions to replace the traditional IT infrastructure. This part will tell the differences between them to help you choose one over another for your network deployment.

Hyperconverged Infrastructure VS Converged Infrastructure

Hyperconverged VS Converged Infrastructure Components

Converged infrastructure defines compute, storage, networking and server virtualization—which are the four core components in a data center—as one dense building block. Hyperconverged infrastructure is born from converged infrastructure and the idea of the software-defined data center (SDDC). Besides the data center’s four core components, hyperconverged infrastructure integrates more components such as backup software, snapshot capabilities, data deduplication, inline compression, WAN optimization and so on.

Hyperconverged VS Converged Infrastructure Principle

Hyperconverged infrastructure is a software defined approach. It means the infrastructure operations are logically separated from the physical hardware, and all components in a hyperconverged infrastructure have to stay together to function correctly. While converged infrastructure is a hardware-focused, building-block approach. Each component in a converged infrastructure is discrete and can be used for its intended purpose. For example, the server can be separated and used as a server, just as the storage can be separated and used as functional storage.

Hyperconverged VS Converged Infrastructure Principle

Hyperconverged VS Converged Infrastructure Cost

Converged infrastructure allows IT to use a single vendor for end-to-end support for all core components instead of the traditional approach where IT might buy storage from one vendor, network from another and compute from another. It also offers a smaller footprint and less cabling, which can reduce the cost of installation and maintenance.

Hyperconverged infrastructure allows IT to build, scale and protect your IT infrastructure more affordably and effectively. For example, a 10GbE Access Layer Switch (8*10/100/1000Base-T+8*1GE SFP Combo+12*10GE SFP+) specially for hyperconverged infrastructure only costs US$ 1,699. And the software-defined intelligence reduces operational management, providing automated provisioning of compute and storage capacity for dynamic workloads.

Conclusion

It is reported that hyperconverged infrastructure will represent over 35 percent of total integrated system market revenue by 2019. This makes it one of the fastest-growing and most valuable technology segments in the industry today. The upfront costs of hyperconverged infrastructure may be a little high now, but in the long term it can pay off.

Latency: What’s the Differences Between Fiber and Copper?

Fiber optic communication has development rapidly in recent years. And in many applications fiber cable has replaced copper cable for higher speed and higher bandwidth applications. Therefore, numbers of people claim that fiber optic lines have lower latency than copper connections, while others do not think so. Then what’s the latency differences between fiber and copper?

fiber-vs-copper latency

Latency in Fiber and Cooper

Before comparing the latency differences between fiber and copper, latency refers to a time delay between stimulation and its response. Usually, it’s caused by velocity limitations in a physical system. Put it in simple terms, latency is the time it takes for a signal to travel from one place to another place. And there are diverse types of latency: network latency, Internet latency, audio latency, WAN latency, etc. No mater in a fiber optic network or a copper network, latency can be described as distance and speed. In addition, latency does exist. It’s just a question of fast or slow. One key factor that affects the latency is the signal speed in transmission media. Fiber and copper are two of transmission media. The type of media used in communication system depends on the bandwidth and transmission distance required by the application.

Fiber Latency

As we know, the speed of light in free space is about 3×10meter per second. While the speed of light in air is slower than that in a vacuum. So does in the glass. Therefore, when an optical signal travels in a fiber link, there are five latency contributors: two are created when the signal moves from the electrical domain to the optical; another contribution occurs as the signal goes through the optical fiber; and as the signal is converted from the optical domain to the electrical, latency occurs.

fiber latency

Copper Latency

Signals in copper cables are easy to be interrupted by around environments, especially in longer distance transmission. The signals will attenuate as distance increases, which will lead to data transmission error, page error and make users feel slow speed at the moment. Actually the transmission speed doesn’t slow slow down. Besides, alien crosstalk also would cause transmission errors and latency.

copper latency

Fiber vs Copper: What’s the Latency Difference?

Signals are transmitted at 2/3 the speed of light in fiber optic cables. In copper it can be faster than that. However, this cannot account for system latency. In longer distance, latency in fiber optic system is lower because of less need for processing and repeating of the signals. While signals in copper are affected by electromagnetic interference and are prone to higher rates of loss over long distances.

In addition, no mater in a fiber optic network or a copper network, latency can be described as distance and speed. In addition, during the whole transmission process, serialization delay that shows how fast a data pocket can be serialized onto the wire, has far more impact on shorter distances. For example, it will take 8ms to serialize a 1500-byte packet on 1.5Mbps link, while it will only need 1.2us on 10Gbps, or less on higher speed. That shows speed makes a significant difference.

Summary

In a word, the latency differences between fiber and copper are influenced by transmission distance, speed and environments. For shorter distance, copper cables can be the first choices, for the delay in it does not mean much and its low cost. For longer distance transmission, fiber cable offers lower latency for the whole network and can be an optimal choice.

Compatible SFP Modules for Mikrotik CRS125-24G-1S-IN & CRS125-24G-1S-RM

Mikrotik CRS125-24G-1S series cloud router switch is available in CRS125-24G-1S-IN and CRS125-24G-1S-RM two models. It combines the best features of a fully functional router and a Layer 3 switch, is powered by the familiar RouterOS. As we know, these two models switch both have one SFP port. Then, what SFP modules can you choose for your switch? This blog will give some choices.

Overview for CRS125-24G-1S-IN and CRS125-24G-1S-RM Switch
As show in the figure below, both CRS125-24G-1S-IN and CRS125-24G-1S-RM switches have 24 RJ45 ports and 1 SFP port. One is a desktop type, and the other is a 1U rackmount type. You can according to your specific needs to choose the right one.

CRS125-24G-1S-IN CRS125-24G-1S-RM

Detailed specifications for CRS125-24G-1S and CRS125-24G-1S-RM are listed in the following table:

CPU Qualcomm Atheros AR9344 600 MHz
Memory 128MB
Ethernet 24x 10/100/1000 Mbit/s Gigabit Ethernet with Auto-MDI/X
Expansion microUSB port
Storage 128MB Onboard NAND with multiple OS partition support
Serial port One RJ45 serial port
Extras Reset switch; beeper; voltage and temperature monitoring, touchscreen LCD
Power options 8-28V, 24V 0.8A PSU included
Case dimensions 285x145x45mm
Temperature -35C to +65C tested
OS MikroTik RouterOS v6, Level 5 license
Included CRS switch, power adapter, and USB OTG cable (for 4G dongle or USB drive)

User Guide for CRS125-24G-1S-IN and CRS125-24G-1S-RM Switch
The CRS125-24G-1S and CRS125-24G-1S-RM are preinstalled with RouterOS and are ready to use. Switch is compatible with RouterOS v6 and newer, if your switch comes preinstalled with an earlier version, please upgrade before using it. For CRS125-24G-1S and CRS125-24G-1S-RM: All the ports are switched. Both models can be accessed though the IP 192.168.88.1, username is admin and there is no password. Please connect with your web browser to this IP address to configure it.

Compatible SFP Modules for CRS125-24G-1S-IN & CRS125-24G-1S-RM Switch
According to Mikrotik cloud router switch guide, CRS125-24G-1S-IN and CRS125-24G-1S-RM switches are compatible with 1.25G SFP modules. SFP+ port supports only modules up to 10KM LR (long reach). FS.COM provides a full range of compatible 1.25G SFP modules at high quality and low price, which can work well in Mikrotik switches. 1000BASE-SX SFP modules are only sold at US$  6.00. Part of the products from FS that are compatible with this Mikrotik CRS125-24G-1S-IN and CRS125-24G-1S-RM switches are listed below for your reference.

FS P/N Description
SFP-GB-GE-T Generic Compatible 1000BASE-T SFP Copper RJ-45 100m Transceiver
SFP-GB-GE-T Generic Compatible 10/100/1000BASE-T SFP Copper RJ-45 100m Transceiver
SFP1G-SX-85 Generic Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver
SFP1G-SX-31 Generic Compatible 1000BASE-SX SFP 1310nm 2km DOM Transceiver
SFP-LX Generic Compatible 1000BASE-LX/LH SFP 1310nm 10km DOM Transceiver

Can A Computer Connected to the PoE Switch?

The PoE switch is commonly used in various networks. It can be low-cost unmanaged edge switches with a few ports or complex multi-port rack-mounted units with sophisticated management. When used in small or home networks, many people may wonder if it can be connected directly with a computer. This post will discuss this question in details.

What Are PoE and PoE Switch

Before the discussion, it is necessary to have a basic understand of what are PoE and PoE Switch:

PoE

As demands for connection from networking devices such as IP phones, IP cameras and access points increase, deployment complexity and cost rise as well. For less cable usage and investment, Power over Ethernet (PoE) technology is developed to provide both data connection and electrical power to devices through just one Cat5/Cat5e/Cat6 cable.

PoE Switch

PoE switch is a network switch that has Power over Ethernet injection built-in, which can transmit both power and data through an Cat5/Cat5e/Cat6 Ethernet cable at the same time. This kind of switch makes it easy for different sectors to deploy powered devices like VoIP phones, wireless access points and IP surveillance cameras in challenging places like ceilings, walls, outdoors, or wherever electrical outlets are not easily available.

poe switch connection

Can A Computer Connected Directly to the PoE Switch?

As shown below,PoE switch usually have the same RJ45 port as a computer. So many people will think they can be connected directly. But do not forget that PoE switch may also transmit electrical power through the RJ45 port and Cat5/Cat5e/Cat6 cable to the computer. Then can a computer be connected directly to the PoE switch? This is largely depend on the switch you have:

poe switch

If you have a PoE switch that conforms to 802.3af (the PoE standard) or 802.3at (the PoE Plus standard) and doesn’t claim to be “passive”, you can definitely connect your computer with it. This is because this kind of PoE switch has the function of PoE detection which is designed to avoid damage to non-PoE devices. In other words, when you connect other network devices to your PoE switch, it will communicate with the these devices whether they need power or not. Power is only injected if and when this negotiation is successful. Ethernet devices such as phones and access points are detected by the switch as accepting PoE and will receive the additional power feature from the PoE switch/port. Whereas a computer and other non-PoE devices will not be detected as having PoE capability and will just use the data communications features of the port.

computer connect to poe switch

However, there exists a class of PoE switches, usually referred to as “passive” or “always on”, which supply power without PoE detection. Why would anyone do this? Because this kind of PoE switch is significantly cheaper. Whether it damages your device depends on the voltage of the passive PoE switch and your devices. For a computer, it may be damaged for excessive voltage or current.

Conclusion

PoE switch is a dedicated device that contains multiple Ethernet ports to provide power and network communications. It is usually used in NVR/IP camera networks. For small or home networks, if you want to connect a computer to the PoE switch, make sure your switch follows the standard 802.3af or 802.3at PoE requirements. So can you connect a computer directly to your PoE switch?