IP SANs: A Guide to iSCSI, iFCP, and FCIP Protocols for Storage Area Networks

11.7. Chapter Summary

Class of Service and QoS

• Class of service is required to give preferential treatment to data as it transits the network.

• Class of service refers to prioritization of different traffic types.

• QoS includes class-of-service features as well as bandwidth allocation and timely delivery guarantees.

• Class of service includes 802.1p link-layer prioritization, IP header TOS bits, and DiffServ.

• QoS includes bandwidth allocation via RSVP and MPLS.

• Standard class-of-service and QoS mechanisms can be leveraged for IP storage networking.

802.1p Traffic Prioritization

• The IEEE 802.1p standard is a link-layer method for assigning priority to a frame.

• A 3-bit prioritization field provides 8 levels of service (levels 0-7) with level 7 representing ...