Justin Cohen of CanTechIt comments:
As networks became constricted in bandwidth (mostly in the WAN) we needed a way to constrain less important traffic. The start of QoS was in the VoIP world – as people like me (hard core telephony guys from the TDM days) started to work on VoIP, we wanted circuit switched performance over packet switched networks. Zero packet drops, little jitter and delay.
We started with ToS (Type of Service) – a small field in the IPV4 header that gave us some bits we could set. 3 bits should be enough for anyone — yeah right, just like “640KB should be enough for anyone”. For most enterprises 8 classes is enough – but for service providers, not so much.
Then there was vendors who treated TOS and DSCP bits differently, or put them into different queues and treated them differently
QoS is second only to routing in the network when it comes to adoption – but how many customers are deploying it properly. Stay with me – we have new tools for you.
Justin takes a very in-depth look at the new Easy QoS tools from Cisco. This has the potential to make a large number of QoS deployments very simple and effective.
Read more at: Cisco DNA Series: The QoS Evolution