VLAN support of differentiated services
The two types of virtual local area networks (VLANs) may be defined: p-bits-Inferred-scheduling class VLAN (p-VLAN); and VLAN-10-Only-Inferred-scheduling class VLANs (v-VLAN). As such, upon receipt of an Ethernet frame, the type of VLAN associated with the Ethernet frame may be determined. The type of VLAN provides the receiving node with an indication of a method of determining a scheduling class. A p-VLAN supports multiple scheduling classes. For a p-VLAN, the scheduling class and drop precedence for the received Ethernet frame may be determined based on a “service map” that describes the relationship between the p-bits and forwarding treatment. A v-VLAN supports a single scheduling class. As such, the scheduling class for a received Ethernet frame may be determined based on the VLAN-10 of the received Ethernet frame. The described VLAN QoS information may be configured or signaled across the network. Advantageously, the methods may be applied in connectionless, connection-oriented and path-oriented Ethernet networks.
1. A method of forwarding frames associated with a virtual local area network (VLAN) in a data network, the method comprising:
providing a service map for a VLAN to nodes of the data network, the service map defining a mapping between predetermined contents of a user priority field in a header of each frame and selected ones of a set of per hop behaviours controlling a forwarding treatment of frames; and
at each node having the service map, associating the service map with a virtual local area network identifier (VLAN-ID) of the VLAN such that each node forwards frames including the VLAN-ID in accordance with the service map.
2. The method of claim 1 , wherein the service map comprises a mapping between each per hop behaviour and a respective frame scheduling class.
3. The method of claim 1 , wherein the service map comprises a mapping between each per hop behaviour and a respective frame drop precedence.
4. The method of claim 1 , wherein the set of per hop behaviours comprises at least one of Expedited Forwarding, Assured Forwarding, Class Selector, and Best Effort.
5. The method of claim 1 , comprising:
providing another service map for another VLAN to the nodes of the data network; and
at each node having the other service map, associating the other service map with a VLAN-ID of the other VLAN such that each node forwards frames including the VLAN-ID of the other VLAN in accordance with the other service map.
6. The method of claim 1 , comprising:
distributing a bandwidth profile associated with the VLAN to the nodes; and
at each node, associating the bandwidth profile with the VLAN-ID of the VLAN such that each node forwards data frames including the VLAN-ID in accordance with the bandwidth profile.
7. The method of claim 1 , comprising, at each node:
receiving a data frame;
determining the VLAN-ID associated with the data frame from a header of the data frame;
based on the VLAN-ID, selecting a service map;
determining a user priority associated with the data frame from the header of the data frame;
determining a per hop behaviour for the data frame based on the selected service map and the user priority associated with the data frame; and
forwarding the data frame based on the determined per hop behaviour.
8. The method of claim 7 , wherein the data frame is an Ethernet frame.
9. The method of claim 8 , wherein the header of the frame comprises an IEEE 802.1Q tag.
10. The method of claim 9 , wherein the IEEE 802.1Q tag contains the VLAN-ID and the user priority associated with the data frame.
11. The method of claim 1 , wherein the VLAN is connectionless.
12. The method of claim 1 , wherein the VLAN is connection-oriented.
13. The method of claim 1 , wherein the VLAN is path-oriented.
14. The method of claim 1 , wherein the service map is associated with a plurality of VLAN-Ids.
15. The method of claim 1 , wherein the service map is associated with a particular network node.
16. The method of claim 1 , wherein the service map is associated with a particular network segment.
17. The method of claim 1 , wherein the service map is associated with a particular network.
18. The method of claim 1 , wherein the service map is associated with a particular interface.
19. The method of claim 1 , wherein the VLAN is a p-bits-inferred-scheduling class VLAN (p-VLAN).
20. The method of claim 1 , comprising:
establishing a path through the data network for the VLAN; and
determining the service map for the VLAN;
wherein providing the service map to the nodes of the data network comprises providing the service map to nodes on the path.
21. The method of claim 20 , wherein providing the service map to nodes of the data network comprises signalling the service map from an edge node of the data network on the path to other nodes of the data network on the path.