Stackwise virtual link bandwidth recommended for 96 1G ports 9494R

[adeebtaqui]

Kindly advise how to calculate the bandwidth minimum needed for interlink for SVL for stackwise virtal link betweek Sups if 9404R having 96 1G ports

Is two 10G port enough?

[MHM Cisco World]

• You can configure up to 8 SVLs in a Cisco StackWise Virtual solution using Cisco Catalyst 9400 Series Switches.

• SVLs can have up to 80GE (8x10GE or 2x40GE) or 50GE (2x25GE) combined bandwidth per chassis
  
  
  

High Availability Configuration Guide, Cisco IOS XE Amsterdam 17.3.x (Catalyst 9400 Switches) - Configuring Cisco StackWise Virtual [Support] - Cisco

[adeebtaqui]

Thanks but want to know how to calculate the minimum bandwidth required or uplinks as virtual links for supporting 96 1G downlinks

[MHM Cisco World]

even if 96 1G traffic path through SVL between two stack you have up to 80

[Joseph W. Doherty · Accepted solution]

Well, if everything is connected to both 9604s, your worst egress failure would be if one of your (48g?) line cards failed.  I.e. in theory, all the traffic that would egress that would have egressed the failed line card would need to be redirected to your other 9604.  So your SVL shouldn't need more than 48Gbps.

However, if neither of your line cards typically uses all 48Gbps, you could size the SVL closer to the busier line card's typical (average) bandwidth usage.

Or, if you're willing to provide "degraded" service until you replace the faulty line card, you could use whatever minimum amount of bandwidth you believe you can get by with.

Since two 10g ports provide 20Gbps of bandwidth, which is almost half of what one 48g line card requires, very good chance that would be acceptable.