A novel traffic-based approach of quaternion (

O

A

P

R

) for failure measuring in transport network is put forward.In order to measure the extent of traffic lost and potential risk incurred by failures

two metrics

Service Outage Index (SOI) and Service Affected Index (SAI)

are defined.They are weight ratios of lost services over total services and affected services over total services respectively.And by connecting these discrete assessment values of SOI and SAI

time-varied continuous assessment functions come into being.Based on them

a new approach of quaternion (

O

A

P

R

) for failure measuring is proposed.In the quaternion

four components represent four corresponding aspects of failures:services lost

potential risks

failure processes

and remarks.The quaternion and other approaches are applied into an example network which is a part

of one carrier’s transport network in China

and the comparison results in whatever single failure or multiple failures scenarios show the quaternion is better than others.