Three criteria are available, although not all qdiscs will use all three: tc filters If tc filters are attached to a class, they are consulted first for relevant instructions. Furthermore, each class contains a leaf qdisc which by default has pfifo behaviour, although another qdisc can be attached in place. Some qdiscs allow for runtime addition of classes (CBQ, HTB) while others (PRIO) are created with a static number of children.
There are two special values: root is signified by major and minor of all ones, and unspecified is all zeros. QDISCS A qdisc, which potentially can have children, gets assigned a major number, called a ‘handle’, leaving the minor number namespace available for classes. This can be useful e.g. for using RED qdiscs with different settings for particular traffic. Shaping is performed using link idle time calculations based on average packet size and underlying link bandwidth. This qdisc may again contain classes, but each class can have only one leaf qdisc.
Рассматриваются радиотелефоны диапазонов 3-50МГц и 900МГц таких известных фирм, как Panasonic, LG Electronics, Samsung Electronics, Sanyo. Each such flow is managed by the CoDel queuing discipline. See tc-fw(8). route Filter packets based on routing table. Reordering is also called prioritizing, and happens only on egress. POLICING Whereas shaping deals with transmission of traffic, policing pertains to traffic arriving. Type of Service Some qdiscs have built in rules for classifying packets based on the TOS field. skb->priority Userspace programs can encode a class-id in the ‘skb->priority’ field using the SO_PRIORITY option.