Author Archives: Serenity Huang

Differentiate the 3 Technologies: Switch Stacking vs Cascading vs Clustering

When we have more than one switches on hand we often seek to a better way in making use of them and managing them. There are mainly three technologies that we might use when we interconnect or combine several switches together, which are switch stacking, cascading and clustering. For many people that firstly get in touch with these terms, they can’t figure out the differences between them. Some discussions of the switch stacking versus switch clustering and switch stacking versus switch cascading have been put forward, but a comprehensive comparison between them has not been made. So this post is a discussion of switch stacking vs cascading vs clustering.

switch stacking vs cascading vs clustering

Switch Stacking vs Cascading vs Clustering

The comparison of switch stacking, cascading and clustering should be based on knowing the meaning of these technologies. So firstly we will see what switch stacking, cascading and cluster are.

What Are Switch Stacking, Cascading and Clustering?

Switch stacking is a technology that combines two or more switches together at the backplane typically via a specialized physical cable (stack cable), so they work like a single switch. The group of switches form a “stack”, and it requires a stack master. There’s also virtual stacking, where switches are stacked via Ethernet ports rather than stack cable/module. In such scenario, switch stacking vs cascading seems to be much similar. The port density or the switch capacity of a stack is the sum of the combined switches. For example, when you cascade two 24-port switches, you will get one large 48-port switch when it comes to configuration. And all the switches in the stack share a single IP address for remote administration instead of each stack unit having its own IP address. Only stackable switches are able to be stacked together. And it should be noted that, when the switches are stacked, there is no need to connect switches in the group via copper or fiber port besides the stacking ports, because the stack logically is one switch. It is like connecting 2 ports together on the same switch, which can cause loop.

By cascading more than one switch you can have multiple ports interconnecting each of your switches in the group. But they are configured and managed independently. Switches that are cascaded together should all support Spanning Tree Protocol (STP), in order to allow redundancy and to prevent loop. Generally switches of any models or from any manufacturers can be cascaded. But it does not rule out the cases that two switches can not be cascaded.

A switch cluster is a set of switches connected together, whether through common user port or special ports. One switch plays the role of cluster command switch, and other switches are cluster member switches, which are managed by the command switch. In a switch cluster only one IP address is needed (on the command switch). Not all switches can be clustered. Only specific cluster-capable switches from the same manufacturer can be clustered. And different manufacturers may use different software for clustering.

Switch Stacking vs Cascading

Where it comes to switch stacking vs cascading, the most obvious difference is that only stackable switches can be stacked while almost all switches can be cascaded. And the stackable switches are generally of the same model or at least belonging to the same manufacture.

In a switch stack, the port capacity is the combination of all the member switches and the bandwidth is also the sum of all switches. But by cascading switches, the bandwidth will not be increased. There’s even possibility of congestion at the cascade ports if you have only one connection between each switch.

The stack is managed as a whole. When you configure one switch, the change will be duplicated to every other switches in the stack, which is time-saving. However, in a switch cascade, you have to manage and configure every switch separately.

Stacking has a maximum number of stackable switches that you can have in a group. For example, you can connect up to four FS S3800-24F4S or FS S3800-24T4S in a stack. The switch cascading has limitation on the layers that you can have, which are usually the traditional three layers topology: core, aggregation and access. When the limitation is exceeded, there might be problems of latency and losing packet.

FS S3800-24F4S or FS S3800-24T4S stackable switch

Switch Stacking vs Clustering

Stacking and clustering is very similar in that a stack or a cluster both use only one IP address, and member switches are managed as a whole. So when you wan to simplify the management of multiple switches, both stacking and clustering are technologies that can be adopted.

Stacking might be a bit easier to configure since the stack can automatically recognize new stack member, while in a cluster, you have to manually add a device to be the switch cluster. The management of stack members is through a single configuration file. Cluster members have separate, individual configurations files. So the management by a stack master is complete on every stack switch, but the cluster command switch is the point of some management for all cluster members.

The distances between clustered switches can be more flexible. They can be in the same location or they can be located across a Layer 2 or Layer 3. But stacked switches are in the same layer and generally they are located in the same rack. Only virtual stackable switches can be placed in different locations.

Conclusion

After reviewing the discussion of switch stacking vs cascading vs clustering, you may find that the three technologies have the similarity that switches in a stack/cascade/cluster group need to be physically connected. Some are through common Ethernet ports, while some are through special stack ports. Cascading has the minimal requirements on the switch model, while both stacking and clustering require the switches to be stackable/cluster-capable, and are of the same model or at least from a single manufacturer. Stacking and cascading are based on hardware implementation while clustering is based on software implementation. The management of a stack is the most complete among the three.

Buy PoE Switch: 48-Port Switch vs 2 24-Port Switches

When we have about 30 PoE and non-PoE mixed connections in our network, the problem of buying a 48-port PoE switch vs. 2 x 24-port PoE switch always puzzles us. If we already have one 24-port PoE switch in use and we’re just adding more ports, we can choose to buy a single 16-24 ports PoE switch or a 16-24 ports Ethernet access switch to connect the increased devices. But as for a newly built network or 30 newly-deployed PoE devices, we have to balance the pros and cons of choosing one 48-port switch vs. 2 24-port switch.

48-Port Switch vs 2 24-Port Switch

PoE Connectivity: 48-Port Switch vs. 2 24-Port Switch Debate

In terms of the cost, usually one 48-port PoE switch will cost more than two 24-port PoE switches of the same model, but it does not mean always. For example, buying the 48-port PoE+ managed switch FS S1600-48T4S is lower than buying two 24-port PoE+ managed switches FS S1600-24T4F. If we have a tight budget and concerns cost saving most, the 1 x 48-port switch vs. 2 24-port switch debate can end here by buying the cheaper choice. Otherwise, we have more factors to consider.

Concerns of Installing 2 x 24 Port PoE Switch

In the options of one 48-port switch vs. 2 24 port switches, if we choose to do the job with two 24-port PoE switches, then we may have to undertake these shortcomings, unless they do not matter in our case. Firstly, two 24-port PoE switches take up more space than a 48-port PoE switch. A fixed-chassis 48-port PoE switch takes up a standard 1 RU space of the rack while 2 x 24-port PoE switch will use more space than that whether it is 1RU size or smaller. Secondly, if the 2 x 24-port PoE switches are not stacked then we have to do trunk between those two switches, which will eat up ports and give you only 46 ports available. At the same time it provides additional potential of bottleneck at the uplink port. Since the internal traffic on a switch is going to be gazillions of times faster than a 1G or even a 10G uplink between switches. But for a 48-port one, it will have less issues with bottleneck/congestion. The last concern is that two 24-port PoE switches are harder to manage than one 48-Port PoE switch, even when stacking the two.

Concerns of Installing 1 x 48 Port PoE Switch

When we decided to install only one 48-port switch versus 2 x 24-port switch, there are also some concerns in practice. The biggest issue is that we lose redundancy. If we have only one switch and it fails, we’re chained until we get the replacement, which could be over 24hrs away. But in a two switches’ scenario, if one switch fails at least half of our devices can still be up and running. Another thing we may lose is the separate placing of the 2 x 24-port switches. If we have a single rack to install them, then there’s no issue but if we want to place desktop switch for IP cameras and IP access points in different offices, we may not go with a 48-port PoE switch.

Suggestions for Selection

After the discussion about 48-port switch vs. 2 24-port switches, here are the conclusions we have. In terms of better performance, the a 48-port PoE switch is over 2 x 24-port switch. There’s less possibility of creating congestion between the two switches at the uplink ports. For easier management of the devices, it is also suggested to go with one single 48-port PoE switch rather than 2 x 24-ports. All ports on the 48-port PoE switch could communicate between them at wire speed. When we need the redundancy, we’d better go with 2 x 24-port PoE switch. If we want to avoid some problems brought by trunking and separate managing, we can choose stackable PoE switches or modular switch with two 24-port modules, which will provide large backplane and can be managed as a whole.

Ending

The concerns that we discuss in this post are general ones that we may have in choosing one 48-port switch vs. 2 24-port switch for PoE devices. The final decision should depend on our key purpose of buying them. The above factors are several things that we can take into account when we face the similar issue.

Related article: How to Choose a Suitable 48-Port PoE Switch?

Comparison of 48-Port PoE Switch Price and Functionality

When it comes to connecting a lot of VoIP phones and IP cameras, a 48-port PoE switch is great for powering them. Whether it is for home use or business use, a 48-port PoE switch can best solve the problems of installing these PoE network devices in places that has no power lines. If you need to know the application of 48-port PoE switch in access and core area, you could read Deploying 48-Port Gigabit PoE Managed Switch in Different Networks. Due to the high capacity and power supply feature, a 48-port PoE switch price is often higher than a standard 48-port Ethernet switch with no PoE. In this post, we will introduce some cheap 48-port PoE switches and do a comparison between them.

48-port PoE switch for VoIP phone IP camera

Comparison of Four 48-Port PoE Switches Prices and Functions

The four 48-port PoE switches that we’re going to discuss are UniFi US-48-500W, TP-Link T1600G-52PS, D-Link DGS-1210-52MP/ME and FS S1600-48T4S. They are inexpensive compared with most enterprise class 48-port PoE switches. Let’s have a look at these switches.

Difference Between the Four 48-Port PoE Switches

The table below gives some basic parameters of these four switches, including the port type, supported data rate, the maximum PoE power consumption, switching capacity and forwarding rate.

Switch Model UniFi US-48-500W TP-Link T1600G-52PS D-Link DGS-1210-52MP/ME FS S1600-48T4S
10/100/1000Mbps RJ45 Ports 48 48 48 48
Gigabit SFP Ports 2 4 4 0
SFP+ Ports 2 0 0 4
Max. PoE Power Consumption 500 W 470.4 W 479.5 W 600 W
Max. Power Per Port (PoE+) 30 W 30 W 30 W (ports 1-8) 30 W
Switching Capacity 140 Gbps 104 Gbps 104 Gbps 180 Gbps
Forwarding Rate 104.16 Mpps 77.4 Mpps 77.4 Mpps 130.94 Mpps
Price US$760.00 to US$1,230.90 US$481.99 to US$725.99 US$988.06 to US$1,028.01 US$689.00

The UniFi US-48-500W is a 48-port Layer 2 access switch. In addition to 48 Gigabit RJ45 ports, it has 2 fiber ports of Gigabit SFP and 2 fiber ports of 10G SFP+. It has a non-blocking throughout of 70 Gbps, which is sufficient for typical home use and most small business use. But compared with the other three 48-port PoE switches, it lacks some Layer 3 features. The other three are Layer 2+ switches that support static routing and access resolution protocol (ARP) inspecting, which are simple but efficient approaches in segmenting and securing the network.

Outwardly, the TP-Link T1600G-52PS and D-Link DGS-1210-52MP/ME are similar in many aspects. They both have 4 Gigabit SFP ports and their switch fabric capacity and forwarding rate are identical. However, the 48 RJ45 ports of T1600G-52PS are all IEEE 802.3at/af-compliant PoE+ ports, while the 48 RJ45 ports of DGS-1210-52MP/ME are not. Only ports 1-8 are PoE+ and the ports 9-48 are PoE. The price of T1600G-52PS is much lower than DGS-1210-52PS but the former one is released in 2015 while the latter one is 2017’s new model. Both T1600G-52PS and DGS-121052MP/ME has no 10G ability.

Obviously the switching capacity (or backplane bandwidth) and forwarding rate of the FS S1600-48T4S are the highest among these four switches. It has four 10G uplink ports, which allows large traffic from the access switch to the core switch and ensures high speed and precise transmission and recording without delay. Meanwhile, it supports the largest power to the device, which is suitable for connecting more PoE network devices. This 48-port PoE switch’s price is lower than two of the other switches.

48-port PoE switch FS S1600-48T4S

Common Benefits and Features of the Four 48-Port PoE Switches

These four 48-port PoE switches’ prices are much lower than that of high-end PoE switches. They are all managed PoE switches equipped with 48 10/100/1000Mbps Rj45 ports of auto-sensing IEEE 802.3af (PoE), which provides a maximum per PoE port output power to each device of 15.4 W. They also support IEEE 802.3at (PoE+), which enhanced the max. per port power consumption to 30 W. All of them have been equipped with fiber uplink ports.

Another common feature is that these four 48-port PoE switches all support easy management. And the managing function is not limited to only one type. They all have an RJ45 console port or a serial port for managing through web-based graphical user interface (GUI, IPv4/IPv6) or command line interface (CLI).

Summary

This post has compared some 48-port PoE switches’ prices and functions. They are generally inexpensive and suitable for both home use and business use. The managing functions are simplified compared with high-end switches, in order to help better management of the network. If you want 10G uplink, UniFi US-48-500W or FS S1600-48T4S are recommended. Before purchasing a 48-port PoE switch, be sure to check the power requirement for your total PoE devices, the standard it complies to and the overall PoE budget of your installation.

Affordable 8-12 ports 10G SFP+ Switches for SMB HCA Expansion

Hyper-converged infrastructure (HCI) has been earning a good reputation in data centers, whether it is of the entire branch offices, the IT duties of small and medium businesses (SMBs) or the virtual desktop infrastructure deployments. HCI offers numerous integrated services such as backup, data protection and solid-state drive storage, and allows seamless management and expansion of various compute, storage and network devices, i.e., users can scale the network flexibly by adding a new appliance to the hyper-converged cluster. For SMBs, the requirements for network switches is not the same as large enterprises when adding a 10G appliance. This post is to suggest some affordable 8-12 ports 10G SFP+ switches for SMBs during hyper-converged appliance (HCA) expansion.

10G SFP+ Switches Requirements for SMB HCA Expansion

In today’s SMBs, applications are requiring higher data rate and some management features. For a SMB with a considerable size, the core switches might be required to a fully-managed switch with strong capacity, high bandwidth and high port count. The switches for the connectivity of the cluster (compute, storage and network devices) may also have many ports. But when adding new appliance to the cluster, the switch usually needs not to be high port count or with high data rate. An 8-12 ports 10G SFP+ switch is generally enough for hyper-converged appliance expansion, which is rational considering the expenditure for expansion as well. The following table gives some 8-12 ports 10G SFP+ switches in the market for your reference.

Switch Model Ports Switching Capacity Fowarding Rate Switching Layer Price
Dell X4012 12 x 10G SFP+ 240 Gbps 178.6 Mpps L2+ $1,063.54
Netgear M4300-8X8F 8 x 10G SFP+ and 8 x 10GBASE-T 320 Gbps 238.1 Mpps L3 $1,719.00
Cisco SG500XG-8F8T 8 x 10G SFP+ and 8 x 10GBASE-T 320 Gbps 238.1 Mpps L3 $2,146.59
FS S5800-8TF12S 12 x 10G SFP+ and 8 x 1GBASE-T/SFP Combo 240 Gbps 178.6 Mpps L3 $1,699.00
D-link DXS-1210-12SC 10 x 10G SFP+ and 2 x 10GBASE-T/SFP+ Combo 240 Gbps 178.6 Mpps L3 $1,055.00

12 10G SFP+ FS S5800-8TF12S

According to the information available, these switches can be got online well under $3K in brand new condition. Suppose that a SMB has a core switch which has a fabric capacity of 960 Gbps, and now it needs to add 5 nodes of 10G speed to the cluster for downstream, an 8-12 ports 10G SFP+ switch will not only give enough ports for current nodes and for uplink to the core, but also gives the SMB space to grow.

These switches have some features in common. These common features are very helpful in SMB network managing and ensuring data quality.

Management and Functionality Services

For all the switches mentioned above, some of them are fully managed switches while some are smart managed switches. But all of them are not limited to web interface management. They also support Command Line Interface (CLI), Telnet (multi-session support), SSH and SNMP (simple network management protocol). The most functions that a SMB might need are all equipped, such as VLAN, port mirroring, LACP (link aggregation control protocol) and RMON (remote network control).

QoS and Security Features

The QoS (Quality of Service) features include ARP (Address Resolution Protocol) inspection, ACLs (Access Control Lists), DSCP remark, etc. These features can contribute a lot in securing the SMB network, for example, with the help of ARP inspection and ACLs, the switch can block fake ARP entries outside the system, so that data frames will not be easily sniffed or modified. Broadcast Storm Control is also supported in order to avoid traffic disorder caused by malicious attack from intruders.

How to Connect These 10G SFP+ Switches?

Although these 8-12 ports 10G SFP+ switches chosen for SMB hyper-converged appliance expansion are relatively low-priced, but the OEM 10G SFP+ fiber transceivers can overburden a SMB if bought in large quantity. Four OEM 10G SFP+ transceivers can cost as much as a 10G SFP+ switch we have found above. Fortunately, there is way to release the SMBs from expensive OEM optics. That is cost-effective 10G SFP+ compatible modules. So the total cost for the HCA expansion will not exceed $3k either. In addition, most OEM switches support third party transceiver modules and DAC cables from third party transceiver vendors.

Summary

In sum, for SMB hyper-converged appliance expansion, the 10G SFP+ switches used to connect the core switch and the cluster need not to be high port count, but should be equipped with enough management functions for SMB applications. An 8-12 ports 10G SFP+ switch is good enough.

Things You Should Know About Wireless Access Point

A wireless access point (WAP or AP) is a hardware device or configured node on a local area network (LAN) that allows wireless capable devices and wired networks to connect through a wireless standard, including Wi-Fi or Bluetooth. A wireless access point acts as a hub of traditional wired network, and a bridge connecting wired and wireless network. An access point connects to a wired router, switch, or hub via an Ethernet cable, and projects a Wi-Fi signal to a designated area. Wireless access points may be used to provide network connectivity in office or family environments, covering dozens of meters to hundreds of meters. Most APs use IEEE 802.11 standards.

wireless-routers-function

Types

Wireless access points can be divided into two types: Simplex AP and Extended AP.

A simplex AP functions as a wireless switch, only transmitting radio signal. When a simplex AP works, it transmits network signal through twisted-pair and converts electrical signal into radio signal after compiling, forming the coverage of Wi-Fi shared Internet access.

An extended AP, commonly known as a wireless router, is mainly applied to Internet access and wireless coverage. Through a wireless router, the share of Internet connection in home Wi-Fi sharing network, as well as wireless shared access of ADSL (Asymmetrical Digital Subscriber Loop) and community broadband can be realized. From security, an access point is different from a wireless router, in that it does not have firewall functions, and will not protect your local network against threats from the Internet.

Difference Between Access Point and Wireless Router

From the appearance, they look almost the same and hard to tell, but they do have subtle differences. A simplex wireless AP usually has a wired RJ45 network port, a power interface, configuration port (USB port or configuration via WEB interface), and fewer indicator lights; while a wireless router has four more cable front-end ports. In addition to a WAN port for connecting higher-up network equipment, four LAN ports can be wired in internal network, and a router has more indicator lights than AP.

wifi-router-vs-access-point

Functions

AP plays the important role of relay, which amplifies the wireless signal between two wireless points, and enables remote clients to receive stronger wireless signal. For example, if an AP is put in place A, and there is a client in place C which is 120 meters away from place A, it can be seen that the signal from A to C has been weakened a lot. If an AP is put in place B (60 meters between A and C) as a relay, the signal of client in C will be effectively enhanced, and the transmission speed and stability can be ensured.

wireless-access-points-function

Another important function of AP is bridging, which is to connect two endpoints and achieve data transmission between two wireless AP. AP is also bridged to connect two wired LANs. For example, there is a wired LAN made up of 15 computers in place A, and wired LAN made up of 25 computers in place B, but the distance between A and B is very far, over 100 meters, and there is no possibility through wired connection, then how to connect the two LANs? AP is needed in both place a and place b to bridge them so that data transmission can be achieved.

The last function is “master-slave mode”, which can achieve one point to multipoint connection. “Master-slave mode” is widely used in connection between wireless LAN and wired LAN. For example, place A is a wired LAN made up of 20 computers, place B is a wireless LAN made up of 15 computers, and B has a wireless router. If A wants to be connected to B, an AP is needed in A. Initiate the “master-slave mode” and connect AP to the router in A, so that all the computers in A can connect to B.

Summary

Most businesses and homes today rely greatly on the wireless access point (WAP) for data transmission and communication. Wireless access point does make our life more convenient. These devices avoid a mess of wired Ethernet cables. Besides, a company, family or school often has to install wired cables through walls and ceilings, while wireless network needs no cables, which contributes great mobility to users.