architecture.md 1.8 KB
title: Network Architecture breadcrumbs:
- title: IT
- title: Network --- {% include header.md %}
Models
Single Layer
- Switching, routing and firewalling is all done on the same layer, with clients directly connected.
Three-layer Hierarchical Model
- Appripriate for large networks spanning multiple regions (e.g. multiple buildings).
- Scales well.
- Consists of three layers.
- Access layer:
- L2 switches.
- Connected to clients.
- Typically one access-layer VLAN spans one or a few access switches.
- Should implement first-hop security.
- Connected upstream to distribution switches.
- Distribution layer:
- L3 switches or routers.
- terminates access-layer VLANs.
- Implements features like filtering and QoS.
- May manage individual WAN connections.
- Connected upstream to core routers and ptionally interconnected with other distribution switches.
- Core layer:
- Routers.
- Provides a backbone between distribution regions and toward external networks.
- Focuses entirely on high bandwidth, low latency, high reliability and high resilience.
- Avoids anything that may slow down traffic, like access lists, policy enforcement, etc.
- It's possible to connect multiple core routers and distribution switches by using a switch.
Collapsed Core
- Similar to the three-layer hierarchical model, but with the core and distribution layers collapsed.
- Appropriate for medium/small sites without multiples regions.
Collapsed Distribution
- Similar to the three-layer hierarchical model, but with the distribution and access layers collapsed.
- Generally not very useful.
Spine Leaf
TODO
Notes
- VXLAN or Q-in-Q may be used to span VLANs over different areas.
- Oversubscription: Less uplink capacity than downlink capacity.
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