In the hierarchical network design, the enterprise LAN network is divided into three independent layers including access layer, distribution layer, and the core layer. In each layer, the enterprise switches are categorified, among which the access switch is a key part at which local end-users are allowed into the network. This article will introduce what the access switch is and how to select the right access layer switches for your enterprise.
Figure 1: Access layer diagram
The access layer, as the lowest layer of the hierarchical internetworking model, is also referred to as the desktop layer. It plays the role of connecting end-users or end nodes such as PCs, printers, wireless access points to the network. The access layer is supposed to facilitate the continuous network connection of the end devices no matter where they are located. In the meantime, the design of access layer must take consideration of the upper layer connections. The access layer must ensure security as the first layer as well as the first line of defense for the network.
As the physical entity of the access layer, access switches are responsible to connect both to the distribution layer switches and to the end devices as well as ensure the packets are delivered to the end devices. Except for ensuring the persistent connection of end users as well as the upper distribution and core layers, an access switch is expected to meet the requirement of access layer including simplifying the network management, providing security services and other specific functions according to the different network environments.
When choosing access layer switches, there are many points to consider as follows.
Port density refers to the number of ports available on a single switch. An access layer switch should support high port density since it is connected to a large number of end-users and devices. It is essential to consider how many devices are required to connect to the access layer, then decide how many switch port number you will need for the access layer.
The port speed of the access switch is the primary concern to end-users. Most access switches come with 10/100/1000Mbps ports. Whether to use Fast Ethernet or Gigabit Ethernet depends on the specific requirements of your network. Though Fast Ethernet is enough for IP telephony and data traffic on most small to medium enterprise networks, its performance is much lower than Gigabit switches. Moreover, it is vitally important to choose high bandwidth uplink ports in case that the uplink port is oversubscribed when the required bandwidth is greater than the available maximum bandwidth to distribution layer switches. Therefore, you’d better choose the access layer switches with suitable port density and types as needed.
Since the access layer is the network edge, it plays a critical role in defense for security. Access control services such as 802.1x must be supported in access layer switches to secure your LAN. Furthermore, access switches should support the segmentation of traffic through VLANs. IP source guard, DoS protection and other techniques should also be provided to prevent security from attacks.
The number of users in an enterprise network changes over time, therefore it is imperative to think about how many users will the network require in the future. The network design needs to meet the requirement for the enterprise environments in the future three to five years so that the access switches you choose can provide the opportunity for the network upgrading smoothly as time goes by. Stackable switches such as FS S3900 series stackable switches are good choices for greater scalability in case of future use. Network managers can stack these Gigabit switches anytime to expand the number of connected devices when the network size grows.
In a high-density access network environment, it is important to consider simplifying the network deployment and management of numerous end devices. Accordingly, access switches should be fast to deploy and easy to manage for network administrators. PoE technology is normally provided as an option for simpler deployment to enable access layer switches to supply power to end devices such as wireless APs and security cameras, providing simplified deployment to a large number of devices in the access layer. FS Gigabit PoE+ switches offer easy management and maintenance with many management modes such as Web GUI and CLI supported for more efficient installation and management.
Cost is a key feature in choosing access layer switches. The cost of a switch depends on many features, such as the port number, the brand, and so on. Owing to the fact that the access switches connect to multiple end devices and the patching of devices in the end-user environment is high, the cost on access layer switches is expected to be as low as possible.
Overall, access switches are supposed to feature with simplicity, reliability, and security. When selecting the access layer switches that fit for the requirements of the access layer, consider twice based on the factors above.