#core switch

Six Indispensable Tips for Choosing a Switch in a Project

How to choose a switch? How do determine the network structure according to the project? We have such questions in most of the projects we do. Here are the six indispensable tips when you choose a switch in a project. 1. Network scale and network layer You can choose the switch according to the network scale and network layer that which the switch is working. The network scales generally are…

Which Wires of 100Mbps and 1000Mbps Network Cables are Used to Power in the POE System?

There are 4 pairs of wires in the standard Cat.5 network cable, while only two pairs of them are used in 10/100Mbps. The following are the two methods allowed in IEEE 802.3af. 1. When the free pin is used to supply power, pin 4 and 5 are connected to the positive terminal, and pin 7 and 8 are connected to the negative terminal. The following diagram shows a 48V power transfer using the free…

Choosing a data switch for your network can be a daunting task, given the myriads of vendors out there who are vying for providing network switches with fancy functions and feature sets. It may get more challenging when deciding which core switch and edge switch to buy: you have to make sure the switch you get is up to date so it can take advantage of latest technologies, and allows you to squeeze every last drop of performance out of the system. So, whether to choose a core switch or edge switch? Let’s go through their functions and roles within a network, and link these with you are gonna achieve, then you may find the answer.

What Is a Core Switch?

A core switch is a high-capacity switch generally positioned within the backbone or physical core of a network. Core switch is also regarded as a backbone device that is vital to the successful operation of a network: it serves as the gateway to a wide area network (WAN) or the Internet, so that you can use it to connect to servers, your Internet service provider (ISP) via a router, and to aggregate all switches. A core switch need to be powerful enough and have significant capacity to handle the load sent to it, which means it should always be a fast, full-featured managed switch.

In a public WAN, a core switch interconnects edge switches that are positioned on the edges of related networks. In a local area network (LAN), this switch interconnects work group switches, which are relatively low-capacity switches that are usually positioned in geographic clusters.

How About an Edge Switch?

As the name indicates, an edge switch is a switch located at the meeting point of two networks. These switches connect end-user local area networks (LANs) to Internet service provider (ISP) networks. Referred to as access nodes or service nodes, an edge switch connects client devices, like laptops, desktops, security cameras, and wireless access points to your network. Edge switches for WANs are multiservice units supporting a wide variety of communication technologies, it also provides enhanced services such as virtual private networking support, VoIP and quality of service (QoS). Generally, smart switches and even unmanaged switches are valid options at the edge of your network. But for some downtime-sensitive applications or where security matters, a managed switch can also be equally used at the edge.

Core Switch/Edge Switch Selection: What Exactly Matters?

To select the appropriate switch for a layer in a particular network, you need to make clear specifications regarding current/future needs, target traffic flows and user communities.

1. Future Growth

Switches comes in different sizes, features and function, choosing a switch to match a particular network involves a solid network plan for any future growth. With that in mind, you would want to purchase a switch that can accommodate more than 24 ports, such as stackable or modular switches that can scale.

2. Performance

When selecting a switch for the access, distribution, or core layer, consider the ability of the switch to support the port density, forwarding rates, and bandwidth aggregation requirements of your network.

An edge switch needs to support features such as port security, VLANs, Fast Ethernet/Gigabit Ethernet, PoE and link aggregation. While a core switch also needs to support link aggregation to ensure adequate bandwidth coming into the core from the distribution layer switches. Also, a core switch support additional hardware redundancy features like redundant power supplies, and hot-swappable cooling fans. So there is no downtime during switch maintenance.

FS.COM Core Switch and Edge Switch Solution

FS.COM offers a large portfolio of Ethernet switches including 10GbE switch, 25GbE switch, 40GbE switch and 100GbE switch, each with different port configurations and moderate to advanced feature sets that tailored for enterprise networks and data centers. The core switch and edge switch in FS.COM are presented as follows.

Core Switch

S5850-32S2Q, S5850-48T4Q, S5850-48S6Q, S5850-48S2Q4C, S8050-20Q4C, N5850-48S6Q, N8000-32Q, N8500-32C, N8500-48B6C

Edge Switch

S3700-24T4S, S2800-24T4F, S3800-24T4S, S3800-48T4S, S3800-24F4S, S5800-8TF12S, S5800-48F4S

Network switches are categorized into different types according to different principles, such as fixed switch and modular switch based if you can add expansion module to it, and managed switch, smart switch and unmanaged/dumb switch depending on whether you can configure it and the complexity of the configuration. Another way to classify the type of a network switch is by the role it plays in a local area network (LAN). In this case, one switch is considered to be an access switch, an aggregation/distribution switch or a core switch. In small networks we do not see core switch. So many people are having questions about what core switches are. Do you know what is core switch? Is there only one core switch in a network? What are the differences between core switch and aggregation/access switch?

What Is Core Switch?

If we spend some time looking up dictionaries for the meaning of core switch, we will find a definition similar to “A core switch is a high-capacity switch generally positioned within the backbone or physical core of a network. Core switches serve as the gateway to a wide area network (WAN) or the Internet—they provide the final aggregation point for the network and allow multiple aggregation modules to work together (An excerpt from Techpedia).” The definition explains its high-capacity feature, the physical location and its function of connecting multiple aggregation devices in network.

What Are the Differences Between Core Switch and Other Switches?

The biggest difference between core switch and other switches is that, core switch is required to always be fast, highly available and fault tolerant since it connects all the aggregation switches. Therefore, a core switch should be a fully-managed switch. But if it is a switch not used in the core layer, it can be a smart switch or an unmanaged switch.

Another difference is that, the core switch is not always needed in a LAN while we may often have the aggregation switch and the access switch. Because in small networks that have only a couple of servers and a few clients, there’s no actual demand for a core switch vs aggregation switch. In the scenario where we don’t need the core layer, we often call it a collapsed core or collapsed backbone since the core layer and the aggregation layer are combined.

The third difference is that there’s generally only one (or two for redundancy) core switch used in a small/midsize network, but the aggregation layer and the access layer might have multiple switches. The figure below shows where the core switch locates in a network.

What Should Be Kept in Mind When Using Core Switch?

The first thing we should keep in mind is that core switch is urgently required in two occasions. One occasion is when the access switches are located in different places and there is a aggregation switch in each place, then we need a core switch to optimize the network. Another occasion is when the number of the access switches connecting to a single aggregation switch exceeds the performance of it, and we need to use multiple aggregation switches in a single location, then the use of core switch can reduce the complexity of the network.

As for specific type and number of core switch that we should adopt in a network, that depends on the scale and budget of our network, including how many servers, clients or lower layers switches we have. For example, say that a small network has 100 users and has 6 48-port Gigabit aggregation switches, a suitable core switch will be like Juniper EX2200, Cisco SG300, or FS.COM S5800-8TF12S.

The second thing is that a core switch should be fully-managed, which means it should support different method of management, such as web-based management, command line interface and SNMP management. Also it should have some advanced features like support for IPv6, built-in Quality of Service (QoS) controls, Access Control Lists (ACLs) for network security.

And generally the connections to the core layer should be the highest possible bandwidth. In addition, since the core switch act as the center of a LAN, it should be able to reach any devices in the network, not directly but within the routing table. A core switch is usually connected to the WAN router.

Conclusion

In the design of a network, there might be access layer, aggregation layer and core layer. Though the core layer is not required in smaller networks, it is indispensable in medium/large networks. And the high-capacity core switch plays an important role in delivering frames/packets as fast as possible in the center of the network. Its contribution can not be underestimated especially in networks where speed, scalability and reliability are key to users.

As a worldwide leader in IT and fiber optical networking, Cisco switches play a leading role in manufacturing network switches and in providing switching solutions for data center and enterprise networks with large and medium-size forms. MikroTik, a Latvian company which was founded in 1996 to develop routers and wireless ISP systems. Their cloud switches are highly favored by many Ethernet users in recent years. And thus, people are entangled with Cisco and Mikrotik switches. This article would give brief introduction to Cisco and Mikrotik switches, and put emphasis on Mikrotik Switches Vs Cisco Switches.

Cisco Switches

According to different usage, Cisco divided their switches into the following categories: LAN Access Switches, LAN Digital Building Switches, LAN Core and Distribution Switches, Data Center Switches, Service Provider Switches, Industrial Ethernet Switches, Virtual Networking and Small Business Switches. And every category has its switching series. The Cisco Catalyst series switch delivers ease of management and configuration for small to medium-sized enterprise wiring closets in a single system, without the need for additional modules. The following list is about the Cisco Catalyst series switch.

Mikrotik Switches

Comparing to Cisco switches, the total amount of Mikrotik switches is much smaller. According to the official website of Mikrotik, there are only twelve Mikrotik switches. Ethernet smart switches and cloud core router switches are two series switches of Mikrotik switches. The cloud core switch, or cloud router switch, abbreviated as CRS, is a highly configurable switch, powered by RouterOS. They are the new products of Mokrotik switches. For the cloud router switch, there are nine models currently available. Here lists three different cases of the cloud core switch:

CRS125-24G-1S-2HnD-IN (integrated wireless, indoor case)

CRS125-24G-1S-IN (indoor case)

CRS125-24G-1S-RM (rackmount case)

Mikrotik Switches Vs Cisco Switches

—CPU

The CPU on both Cisco and Mikrotik switches is used for management purposes (snmp stats, cli management, etc) and it does not affect the data path. Switching is not done in CPU, neither on Cisco nor on Mikrotik. Switching is done on dedicated ASIC chips specifically designed for this job (thus giving wirespeed). So comparing the CPUs won't mean much about forwarding performance - which is the metric you should care about.

—Power Consumption

One of big problems with Mikrotik switches is their power. The buyers would prefer to pay another couple hundred dollars to have dual power supplies that are removable. And thus, many Ethernet users cannot use Mikrotik in these cases. Comparing to Mikrotik switches, Cisco switches have less power consumption by their advanced technology.

—Network Monitoring Software Systems

Most network monitoring software systems natively understand, support and auto-detect Cisco devices and support Cisco SNMP OIDs (CPU, temp, load, bandwidth, errors, power supply status, and many other sub-system counters in a Cisco device.

When configuring your existing network monitor system(s), your network monitor system(s) may not even know what a Mikrotik is and probably does not have native built-in MIBs/OIDs used by SNMP to auto-check/monitor a network. Thus, an administrator would probably need to configure the Mikrotik graphic icons and configure all of the SNMP checks for MIBs/OIDs from/to a Mikrotik.

Mikrotik Switches Vs Cisco Switches: How to Select?

When considering buying a new switch for your small business, you need to ask yourself a few questions: How many devices will the switch need to support? What kinds of devices will I be connecting? Has our network grown to the point where we need a switch with more advanced management capabilities? And here is an important decision you are going to make: whether core or edge for your network.

What Is A Core Switch?

A core switch, is also known as a backbone switch. It is a high-capacity switch generally positioned within the backbone or physical core of a network. Core switches serve as the gateway to a wide area network (WAN) or the Internet—they provide the final aggregation point for the network and allow multiple aggregation modules to work together. You use it to connect to servers, your Internet service provider (ISP) via a router, and to aggregate all switches that your company uses to connect crucial pieces of equipment that your company can’t afford to lose to downtime. As a result, your core switch should always be a fast, full-featured managed switch.

What Is An Edge Switch?

An edge switch also is called an access node or a service node. It is a switch located at the meeting point of two networks. These switches connect end-user local area networks (LANs) to Internet service provider (ISP) networks. Edge switches can be routers, routing switches, integrated access devices (IADs), multiplexers and a variety of MAN and WAN devices that provide entry points into enterprise or service provider core networks. Edge switches can directly connect client devices, such as laptops, desktops, security cameras, and wireless access points, to your network.

Core Switch vs. Edge Switch

Generally speaking, a core switch would have more up-market features such as higher backplane speed, layer 3 including routing protocols such as OSPF, and physical redundancy features such as removable PSUs. They might not have any copper presentation at all. A core switch will typically have deeper buffers, such that multiple connections can be experiencing congestion.

Edge switches are what your desktops and phones plug directly into (at the “edge of the network”). Typically they are lighter on features and more about copper port count and some form of fibre interface into the backbone / core.

How Should I Make A Choice?

A small company with fewer than 100 employees should function well with one core switch. However, as your business—and your network—grow, you might need to expand the number of core switches to two or more. In this case, you might want to consider stackable switches, which further simplify management.

Edge switches generally are considered less crucial than core switches to a network’s smooth operation. If there are areas of the office such as a conference room where you don’t need the features of a fully managed switch, your company can save some money by installing smart switches. But if you can’t tolerate any downtime whatsoever, want to maintain tight security throughout your office, or have the infrastructure to be able to add multiple different types of applications in the future, you should consider outfitting your entire network with managed switches.

Conclusion

As an important part of the whole network deployment, switch can be divided into many types according to different requirements, such as managed switch, 8 port PoE switch, lay2 switch, core switch and son on. Also, there are various band manufacturers on the market. How to choose a right fiber switch from a broad range of switches for your network deployment? This article will share some tips with you.

Case Analysis

Before we come to the useful tips, let’s have a look at a case.

Case description: I’m planning a large network deployment and I need a 10Gb fibre switch as the core switch to connect the distribution switches in a Metropolitan Area Network to the Datacenter. The scenario is a campus type setup. Ten separate buildings, between 50 and 600 meters away, connecting centrally to a Datacenter and NOC. At least 12 ports are need. The goal is to have high-speed connections to all buildings, preferably 10GbE, using fiber optic cable for the distance. So far I’m hoping for an lay3 core switch with SFP+ ports.

Case analysis: At first, you have to make a decision on singlemode or multimode fiber. If you choose singlemode fiber, you can use SFP-10G-LR-S transceiver for up to 10km. If you plan to to use multimode fiber, you are limited to 400m (on OM4) when using SFP-10G-SR-S transceiver. As for switch, any modern Cisco switch with SFP+ slots will support those transceivers, such as Catalyst 2960X, 3560X, 3650, 3850 etc. For the main site where you are bringing in connection from 10 buildings, you will need a switch with more than a couple of SFP+ ports. You can choose from Catalyst 3850 (WS-C3850-12XS for example or -24XS or -48XS versions for more ports), Catalyst 4500X (WS-C4500X-16SFP+, also available in 32 port version and either model can add an 8 port expansion module).

Figure 1. Catalyst 3850 10G SFP+ Switches

Figure 2. Catalyst 4500X 10G SFP+ Switches

In addition, the 3850 switches can be stacked (except the 48 port all-SFP model), making adding in redundancy quite simple. The 4500X requires configuration of a Virtual Switching System (VSS) pair across two switches for redundancy. Either way ends up presenting a single control plane for configuration. (i.e., one configuration to manage). If you're not well-versed enough in Cisco to be familiar with the basic switching offerings, I would not advise the Nexus switches. NX-OS is a bit different than IOS operating system and the features of the Nexus switches are aligned more with data center use cases than enterprise core. That said, they are perfectly capable for most uses—they just require a bit different configuration.

Tips for Choosing A Right Fiber Switch

From the above case, we can summarize some tips:

First, you have to make sure what type of fiber optic cable you want to use. For long distance, singlemode fiber is recommended; for short distance, multimode fiber can do well.

Second, according to your choice of fiber optic cable, you have to make a decision on data rate fiber optic transceiver. You have to know that which level you want your network to perform at? 10G, 40G or 100G? As for transceiver, usually, SR transceiver is used for short link and LR transceiver is applied for long distance transmission.

Third, you must figure out how many ports you need. If you want 12 port 10G SFP+, then you can buy Catalyst 3850 WS-C3850-12XS. If you want both SFP and 10G SFP+ ports, then you can try MikroTik CRS226-24G-2S+IN.

Fourth, you have to know that the operating system in switch varies from each other, for example, Cisco Nexus Series switches use NX-OS operating system.

Conclusion