The Distribution layer is the second layer in Cisco’s three-layer hierarchy. The switches connected in this layer are called distribution switches. Unlike access switches, distribution switches do not provide any services to end devices. The following article DNG Corp will introduce to readers what the Distribution layer is and how to choose the right Distribution Switch for your business.
What is a Distribution layer?
Cisco’s three-layer hierarchy includes: the Core layer, the Distribution layer, and the Access layer. The Core layer is considered the backbone of the network. This layer provides high-speed connections between different distribution layer devices. The Distribution layer is responsible for connecting the Access layer to the Core layer. The Access layer provides initial connections to end users.
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It can be understood that the Distribution layer is the link between the core layer and the access layer, responding to communications to reduce the load on the core layer during data transmission in the network.
What is distribution layer?
The distribution layer is the intelligent layer in the three-layer model. Routing, filtering, and QoS policies are all managed at the distribution layer.
Distribution layer devices also typically manage WAN connections for individual branch offices in the enterprise. The distribution layer must determine the fastest path to meet user requests. From there, they send requests to the core layer. The core layer is then responsible for forwarding these requests to the correct corresponding service needed.
The distribution layer is capable of performing many important functions in the enterprise network system. DNG Corp has helped you summarize some of the functions of the distribution layer as follows:
- Provide policy-based connectivity: Ensure traffic from one network is forwarded to one interface, while other traffic is forwarded to another interface.
- Redundancy and load balancing.
- LAN and WAN connection aggregation.
- Quality of service assurance.
- Address hierarchy, combining partitions.
- Broadcast or define multicast transport domains.
- VLAN routing.
- Redistribute different routing protocols.
- Transport intermediary.
- Differentiate between dynamic and static routing protocols.
- Filter out destination or source addresses, filter output and input ports.
- Filter routes to hide internal network numbers.
- Define QoS mechanisms such as priority-based queuing.
What is a Distribution Switch?
A Distribution Switch is a Switch device that operates in the distribution layer. At this point, they receive traffic from the access layer and forward it to the core layer. At the same time, they are responsible for determining workgroup access and providing policy-based connectivity.
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However, the aggregation switch is not a mandatory device. Access switches can be directly connected to the core switch without going through the aggregation switch. This method is often used when the transmission distance is short and the core layer has enough access ports to connect directly to the access layer. As a result, businesses can save costs, reduce maintenance burden, and monitor network conditions more easily.
Distribution Switch operates at the distribution layer.
What is the function of Distribution Switch?
Distribution Switch aggregates traffic from the access layer, then forwards and converts data packets. As a device in the Distribution layer, the distribution switch has the following outstanding useful functions:
- Handles local routing, filtering and balancing of traffic.
- Manages QoS priority and security mechanisms.
- Translates IP, traffic shaping and multicast management based on user traffic of the access layer.
- Forward user traffic to the switching core layer or local route.
- Completes conversion of various protocols such as route aggregation and redistribution.
- Ensures that the core layer is connected to areas running on different protocols.
- Factors to consider when selecting Distribution Switches
Under the condition that the same port type, density and port speed are the same, we need to focus on the forwarding speed of the Switch according to the requirements of the distribution layer. Below are factors that businesses need to consider when choosing Distribution Switches.
Các yếu tố cần cân nhắc khi lựa chọn Distribution Switches
Layer 3 Functions
Layer 3 data processing has always been the responsibility of distribution switches. Because the traffic generated by access layer devices must be segmented into VLANs, higher layer switches are required to provide inter-VLAN routing functionality to allow multiple VLANs to communicate with each other.
Since the core layer has the heavy task of handling extremely large traffic forwarding, distribution switches with Layer 3 functionality are set up to reduce the workload of core switches.
Forwarding Speed
Forwarding speed represents the processing capability of a Switch in terms of the number of data that the Switch can process per second. This is an important factor to consider when selecting a Distribution Switch.
Generally, the forwarding speed of distribution switches is higher than that of access switches. If the packet forwarding rate is too low, the distribution switch will not be able to handle the full transmission speed.
Redundancy
Redundancy is also an important factor to consider when selecting distribution switches. Experts often recommend choosing distribution switches that support multiple hot-swappable power supplies to achieve higher redundancy.
With redundant power supplies, distribution switches can still operate normally without affecting network traffic even if one power supply fails. Users can replace the power supply with a new one while the remaining power supply continues to operate normally.
Link Aggregation
To forward all traffic generated from the access layer to the core layer as quickly as possible, distribution switches must support link aggregation to increase network performance by balancing traffic across a series of links. In addition, another important feature is to help quickly recover aggregate links when a failure occurs.
Security policy
Security policy is an important factor applied on distribution layer switches to prevent indiscriminate traffic from passing through the network, while allowing others to pass through.
With the use of security policies such as access control lists (ACLs), distribution switches can determine which types of traffic are allowed to communicate and which types of traffic are not suitable for the ACL rules defined on the switch. This helps administrators ensure security for the entire enterprise network.
QoS capacity
Intelligent QoS settings are essential to achieve network capacity efficiency. Since there are many users sending traffic of different types in the LAN, deploying QoS-enabled switches at the distribution layer will help read packets and prioritize distribution based on policies to allow important traffic to be prioritized first. This will ensure that voice and video data communicate at the appropriate bandwidth.
In short, the Distribution layer is the second layer in Cisco’s three-layer hierarchical model. The switch working at this layer is called a distribution switch, which receives traffic from the access layer and forwards it to the core layer, determines workgroup access, and provides policy-based connectivity.
To choose the right Distribution Switch, businesses need to consider a number of factors such as: port type, port density and port speed, Layer 3 functionality, forwarding speed, redundancy, link aggregation, security policy, QoS capacity.
DNG Corp – Vietnam’s leading provider of in-depth technology solutions in the field of ICT systems. We are committed to bringing your business quality products and services from prestigious global technology brands, one of which is the Soltech brand with its outstanding product line of Layer 3 Switches. Contact us via Hotline: 0983 959 796/ 0988 712 159, Email: sales@dngcorp.vn or Fanpage DNG Corp for comprehensive free consultation.
