The daisy-chain method of creating priority involves serially connecting all devices requesting interrupts. Highest priority devices come first, followed by lower priority devices, and lowest priority devices last in the chain. This connection technology between the three devices and the CPU. The interrupt request line is averaged across all devices to form a wired logic connection. When the device’s interrupt signal is low, the interrupt line goes low, enabling the CPU’s interrupt input. If no interrupts are pending, the interrupt line stays high and there are no interrupts identified by the CPU. This is similar to the negative logical OR operation.
Daisy-Chaining of Switches :
Daisy-Chaining of Switches is not recommended. It will have a single point of failure, which we should avoid.
2-Tier Architecture :
2 tier architecture is a network architecture concept. It has two layers.
- Access layer: It consists of all the LANs which are connected to the switches.
- Distribution layer: This layer has a multi-layer switch to which every LAN switch is connected.
This 2-tier architecture is not ideal because it has a single-point failure when a multi-layer switch fails. But this is a better architecture than the above-mentioned designs. the multi-layer or layer 3 switches are further connected to the router.
- Single point failure when the layer-3 switch fails.
- It has two layers.
2 tier architecture
Ideal 2-Tier Architecture:
To reduce the single point failure in 2-tier architecture, a new concept came in, and it’s called Ideal 2-tier architecture. Ideal 2 Tier Architecture is also called 2-Layered Collapsed Core Model. In this layer, the distribution layer has two multi-layer switches to reduce single-point failure. Many small enterprises that could not afford 3 Tier architecture are still using this design.
- Ideal.
- It has a distribution layer and an access layer.
- But it has less number of single-point failures.
- Reliable than normal 2-tier architecture.
Ideal 2 tier architecture
3-Tier Architecture:
To provide much more reliability, the 3-tier architecture concept came in. large enterprises use this architecture. This architecture is much more complex than the 2 tier. It has 3 layers.
- Access layer: It consists of all the LANs which are connected to the switches.
- Distribution layer: This layer has two multi-layer switches to which every LAN switch is connected and these multi-layer switches are also connected to each other.
- Core layer: To handle traffic much faster way, it has extra two layer-3 switches which are often called the backbone of the architecture.
This architecture is complex and costly, that’s why it’s only used by large enterprises who can actually afford them.
- Ideal design.
- It has a core layer, a distribution layer, and an access layer.
- Less single points of failure.
- much costly.