1. It's possible to rewrite DSCP values at each hop.
2. It is likely these DSCP values are not used for prioritization over other services.
The most likely scenario in my mind: Comcast's trust boundaries could encompass a large enough portion of their CDN to simply not re-write of the DSCP values. Meaning this DSCP value may represent an internal network prioritization, but not impact the traffic delivery outside of their data centers. The traffic, because it originates within the trust boundary, retains its previously assigned DSCP value, but it does not indicate what policies are implemented in the actual delivery of the packet.
This post, while very interesting, simply cannot know with certainty that comcast is prioritizing traffic without conducting an extensive test. We're talking many gigabytes of traffic and many locations. However, this does warrant testing as the DSCP values could easily be used to implement prioritization.
2. It is likely these DSCP values are not used for prioritization over other services.
The most likely scenario in my mind: Comcast's trust boundaries could encompass a large enough portion of their CDN to simply not re-write of the DSCP values. Meaning this DSCP value may represent an internal network prioritization, but not impact the traffic delivery outside of their data centers. The traffic, because it originates within the trust boundary, retains its previously assigned DSCP value, but it does not indicate what policies are implemented in the actual delivery of the packet.
This post, while very interesting, simply cannot know with certainty that comcast is prioritizing traffic without conducting an extensive test. We're talking many gigabytes of traffic and many locations. However, this does warrant testing as the DSCP values could easily be used to implement prioritization.