Orhan Ergun No Comments

Spanning Tree Best Practices

Spanning Tree Protocol (STP) is a control plane mechanism for Ethernet. It is used to create a Layer 2 topology (a tree) by placing the root switch on top of the tree.

Since classical Ethernet works based on data plane learning and Ethernet frames don’t have TTL for loop prevention, loops are prevented by the STP blocking the links.

As you can see from the below figure, some links are blocked by the spanning tree. If Spanning Tree wouldn’t block those links, loop would occur in the below topology.

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Orhan Ergun 5 Comments

Datacenter Design: Shortest Path Bridging

IEEE 802.1aq Shortest Path Bridging (SPB) uses IS-IS as an underlying control plane mechanism that allows all the links in the topology to be active.

In sum, it supports layer 2 multipath. SPB is used in the datacenter; however, it can also be used in the local area network. In this article, Figure-1 will be used to explain shortest path bridging operation.

leaf and spine


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