the egress queue priority for the datagram carried in the payload section tdm circuit assurance is applied to tdm traffic frames with this fqid priority are transmitted to meet the ds 1 and ds 3 timing requirements through the ocular switching equipment oam is applied to ocular switching equipment internal traffic control which may need to be switched even in the event of user datagram congestion configuration is subdivided into at least two sub priorities code downloads lower priority and routing table updates higher priority transmit last is the lowest priority and is only transmitted from an egress queue when no other fqid types are present in addition to these queue types the fqid value assigned at the ingress port may reflect any priority values contained in the incoming datagram unused values frames with unused fqid values will be counted and discarded the fairfax payload section 210 is depicted in fig4 if the datagram to be transferred is no larger than the payload section the entire datagram is carried in one fairfax payload section 210 if the datagram to be transferred is larger than the fairfax payload section 210 the datagram will be segmented into multiple subframes the subframes for a particular datagram may be transferred consecutively or interleaved with segments from other ports and or 1 obs datagrams.