vPC best Practice in Cisco Datacenter Environment

Today I am going to talk about the quick facts on the vPC best practices in the datacenter environment. 

Basics about vPC, A virtual port channel (vPC) allows links that are physically connected to two different Cisco Nexus 7000 Series devices to appear as a single port channel to a third device. The third device can be a switch, server, or any other networking device that supports link aggregation technology.

Fig 1.1- Cisco DC vPC Best Practice

Best Practices in vPC best Practices

  1. Manually define VPC primary and VPC secondary switch
  2. Form L2 channel with diverse 10GE modules for VPC peerlink  ports in dedicated mode.
  3. Form L3 channel with diverse GE modules for VPC peer keepalive link (non-default VRF).
  4. Enable BA on VPC peerlink interface (default)
  5. Enable UDLD aggressive on VPC peerlink interface
  6. Align STP root, HSRP active router and PIM DR with VPC primary switch
  7. Align STP secondary root, HSRP standby router with VPC secondary switch
  8. By eliminating L2 loops with VPC, BA and Loopguard are not needed on access switches
  9. Enable spanning-tree port type edge on host ports
  10. Enable spanning-tree BPDU guard globally

VPC With Single 10GE I/O Module

  1. Implement L3 GEC between VPC peer switches to protect against single point of failure
  2. Enable IGP routing on the dedicated interface
  3. The amount of bandwidth depends on customer requirement

Common Layer-3 Features

  1. Use default IGP timers in a dual supervisor system to avoid unnecessary network convergence during supervisor failover
  2. Reduced IGP timers (1 sec hello and 3 sec hold timer) improve IGP convergence over L2 cloud.
  3. Implement consistent auto-cost reference bandwidth. IOS default is 100M and NX-OS default is 10G.
  4. With large number of FHRP groups, limit the control plane load and FHRP timers should not be tuned to less than 1 sec hello and hold 3 sec hold timer.
  5. Other L3 best practices includes passive-interface, routing authentication, route summarization and preemption delay

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