Campus switches are an integral part of any network, responsible for end-to-end connectivity within any organization. Every network is unique in terms of its geographical location, kind of applications and most importantly number of users. Any network design is possible only after careful evaluation of the types and numbers of switches.
Selecting campus LAN switches depends on a number of factors, ranging from cost effectiveness, port connection types, port speed, usefulness, security, troubleshooting features, throughput, redundancy, working environment to whether the switch requirement is of core, access or distribution.
With time campus LAN switches have progressed a lot in terms of integration, performance and configuration specification (an ever-increasing number) but still the campus LAN design model is more or less the same for quite a while. Marketing tactics used by switch vendors and growing number of features has made it rather difficult to distinguish between campus core switches, distribution layer switches, and access layer switches.
Below is a brief description of factors to consider when choosing a campus LAN switch. It is important to note that these factors depend upon whether the required switch is for access, distribution or core.
Access switches are the devices that connect directly with the end-user equipment and typically work at Layer 2. They usually have high-port density but with low throughput per port. Distribution switches sit between access and core switches. They connect all the access switches using medium-powered, often fiber optic, ports. They operate at both Layer 2 & 3. Core switches are the most powerful ones with fewer high-capacity ports. Core switches act as the gateway to WAN or the Internet. They must be highly fault-tolerant.
Cost, scalability, port density, port speed, security are among the factors to consider when buying access layer switches.
Cost of any unit depends on whether it is designed for fibre optic ports or RJ45 ports, number of ports, with or without PoE support.
Number of users does vary over a period. Any selection of switch must be done while keeping in mind user traffic for the next three to five years.
Number of ports on any switch (port density) is an important factor. Since the number of users is bound to increase in future therefore a switch with more ports is a better choice.
Port speed facilities user data requirement. Most access switches come with 10/100/1000Mbps ports. Choice of Fast Ethernet, Gigabit Ethernet depends on the particular requirements of a network. Some access switches offer PoE (Power over Ethernet) capabilities which allow them to power devices over the Ethernet cable without the need for an external power source which is pretty handy in some scenarios.
Support of services like 802.1x, segmentation of traffic through VLANs. IP source guard, DoS protection and techniques to prevent attacks is vital for security in a LAN switch.
Performance, reliability, redundancy, QoS capability, port speed, port types and scalability are vital features of any core switch. These factors must be carefully studied when selecting network core switches.
Performance of a core switch is a measure of its switching capacity and packet-forwarding rate. The core switch must have the highest forward rate and as much switching capacity as possible.
Routing and switching are main tasks of a core switch along with desired features of security and reliability by performing DDoS protection using layer 3 protocols. Fault tolerance is also an important issue in terms of reliability.
Redundancy in power supply is critical for core switches, due to higher workload core switches get hotter compared to access and distribution switches. A redundant cooling system is also desirable to tackle this issue.
With an ever-increasing traffic of voice and video data, QoS capability is a necessary feature of a core switch. With QoS capability core switches are able to provide bandwidth according to the type of user application.
Layer 3 function, forwarding rate, port density, port seed are factors to consider when selecting a distribution layer switch. Layer 3 function means processing Layer 3 data which involves inter-VLAN routing and forwarding functions. VLAN routing enables communication of multiple VLANs and forwarding functions help ease workload of core switches.
Selection of a campus LAN switch depends upon user needs; a wise choice is possible only after careful consideration of above-mentioned factors.