20:1 4:1 Oversubscription

[NETAD]

Hi guys, 

I'm trying to apply Cisco recommendation for 20:1 and 4:1 oversubscription rate but I need your help understanding it first. Does it mean 20GB for 1GB uplink? 

Here's our senario 2 3850 stacks for distribution/core or collapsed core and 3 stacks of 48 ports 2960'x for the access layer with 2 uplinks to the distribution. How many uplinks from my access layer to the distribution layer is needed here accounting for bandwidth and oversubscription. 

Thanks 

[Carlos Villagran · Accepted solution]

Hi!

Exactly that is what it means, twenty times the uplink capacity. Well, this depends completely in the traffic of your network, the consideration of how much traffic in input is going through, let say you have 4 10G input links which will be sending almost at full capacity everytime and the output link is only one 10G link, you will get oversubscribed, no doubt.

However, a nice solution is to use the etherchannel solution for your uplink, with a well done configuration and correct load-balancing of course.

Hope it helps, best regards!

JC