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last change: November 13, 2022

Class of Service (CoS) at ACOnet

Class of Service (CoS) is a mechanism to mark data packets according to predetermined rules. The CoS implementation within ACOnet marks incoming traffic at the borders, depending on the inbound interface. At the interface to the participants, the CoS is evaluated. Different rules apply to the data packets depending on their marks and therefore depending on their origin.

This mechanism is used to distinguish data packets from commodity networks from data coming from other ACOnet participants or from other NRENs within GÉANT:

  • Data packets coming from commodity sources are limited to the participant's subscribed internet bandwidth (max. 1600 % burst capacity).
  • Without regard for the respective commodity bandwidth subscribed, data packets marked as scientific resp. local traffic will not be limited by ACOnet, but only by the capacity of the participant's uplink to ACOnet. Traffic sent by ACOnet participants is classified as scientific and therefore also no limitation is applied.

Packet marking

Marks are applied by setting the DSCP-field in the IP-Header (DSCP = Differentiated Services Code Point). The DSCP values used within ACOnet are as follows:

Scientific and local Internet traffic (unlimited)

  • DSCP 32 (binary 100000):
    ACOnet participants, GÉANT NREN traffic

  • DSCP 36 (binary 100100):
    bilateral NREN peerings (CESNET / SANET / PIONIER),
    Vienna Internet eXchange (VIX), GÉANT Peering Service

Commodity Internet traffic (limited)

  • DSCP 34 (binary 100010):
    Hurricane Electric, next layer

Packets delivered to participants retain their marks. Participants therefore can ascertain wether data packets originate from commodity (limited) or scientific (unlimited) sources. Moreover, all participants can view their respective CoS-based traffic statistics at the Webportal.