Vahid Tavajjohi

Author Archives: Vahid Tavajjohi

HA inside Data Center


In Leaf/Spine VXLAN based data centers, everyone likes to provide HA with Active/Active in it, so choices are different. There are two types of HA in data centers, Layer 3 and Layer 2.

For layer 3 HA, always there is more than one spine that can provide ECMP and HA at same time. However, Layer 2 redundancy for hosts and l4-l7 services that connected to leafs are more than an easy choice. As Cisco provided vPC for nearly 10 years ago, almost this was the first (and only) choice of network engineers. Also, other vendors have their own technologies. For example, Arista provided Multi-chassis Link Aggregation (MLAG) for L2 HA in leafs. But, there is always a problem in implementation of them. One example in vPC is “peer-link” that is an important component in the vPC feature. However, it can be a tough one in most cases like Dynamic Layer-3 routing over vPC or Orphan members that may cause local traffic switching between vPC peers without using Fabric links.

To address the “peer-link” issue, there is a “fabric-peering” solution that uses Fabric links instead of “peer-link” and convert it to “virtual peer-link”. With this solution there is no concern Continue reading