Link over-subscription at LA USD and Orange County DoE

The next two graphs show traffic (first graph) and delay and jitter (second graph) on the OC-3 155 Mb/s link from Tustin-DC1 to LA-USD. In the traffic graph, solid green is from CENIC toward the USD. The school organizations consume more bytes of traffic than they produce.

The smokeping target for the second panel is the Cisco Cat6509 that is one hop beyond the last CENIC router. Absent congestion, the ping round trip time between UCSC and Los Angeles is 16 millisconds. While the excess delay could occur anywhere between UCSC and LA-USD, we know from other measurements that it is all due to queuing outbound from Tustin. The units on the smokeping graph are milliseconds. That the median bars are all green means there is delay but no packet loss.

In the traffic graph, solid green is from CENIC toward the USD. The school organizations consume more bytes of traffic than they produce.

LA-USD

The Orange County graphs are the same as Los Angeles. The over subscribed link is from LAX-DC2 to OCDE. Here our smokeping target is their Packeteer - 209.79.69.215. Cisco 7507 routers (CENIC hardware in Orange County) add jitter (smoke) to the graphs that is not characteristic of thru-traffic.

Orange County Dept of Education

Cal Poly Pomona

Cal Poly Pomona has a Cisco 7204 CENIC edge router at the campus. The traffic stats are collected at the campus edge rather than the CENIC core, which reverses the colors. The blue 'almost overload' is input to the campus. Pomona also has outbound overload episodes (not shown here). An almost overload of 140 Mb/s out of 150 possible adds only a small amount of jitter. Here the smokeping target is the 7204 router.