Resource management refers to the implementation of different protocols in order to offer relative quality of service (QoS) or guaranteed QoS in an Ethernet network (Figure 9.1).
Relative QoS is associated with the marking of the Ethernet frame. This marking is carried by the PCP (Priority Code Point) field. This field is jointly introduced with the virtual local area network (VLAN) marking of the Ethernet frame. The marking of the Ethernet frame should be carried out at a trusted piece of equipment (switch, router, possibly a host station). Mapping can be established between the PCP marking of the Ethernet header and the DiffServ Code Point (DSCP) marking of the Internet Protocol (IP) header.
Ethernet technology is also deployed in the wide area network (WAN):
– at the access network. The GPON (gigabit passive optical network) and EPON (Ethernet passive optical network) are point-to-multipoint Ethernet networks over optical fibers. Specific mechanisms carry out bandwidth allocation among the different traffic classes of different users;
– at the aggregation network. Ethernet frames inherit an additional marking.
Guaranteed QoS is an extension to the IntServ model for which the SBM (Subnet Bandwidth Management) protocol performs resource reservation within the local area network (LAN). The demand for resources generated by the host station or the router is catered for in the traversed switches for the generated ...