Backbone Provider Bridging Networks
An edge device is used to support a backbone provider bridging network to facilitate interconnection of a plurality of networks. The edge device is coupled between the backbone and a first one of the networks, and is operable to encapsulate data units received from the first network with a header, and to forward the encapsulated data unit to the backbone. The header is indicative of a tunnel that is used to support traffic from the first network to a second network over the backbone. The edge device also de-encapsulates data units received from the backbone that are destined for the first network.
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This Application is a continuation of U.S. patent application Ser. No. 11/159,065, filed Jun. 22, 2005, titled Backbone Provider Bridging Networks, which a claims priority to U.S. Provisional Patent Application Ser. No. 60/582,316, entitled Backbone Provider Bridging Networks, filed Jun. 23, 2004, which is incorporated by reference.
FIELD OF THE INVENTIONThis invention relates generally to the field of network communications, and more particularly to interconnection of provider bridge networks.
BACKGROUND OF THE INVENTIONEntry of new communications service providers into the marketplace combined with the breakup of some state-regulated communications monopolies has resulted in increased network complexity. In particular, communications services that might once have been supplied by a single service provider may now require interaction between the individual bridge networks of multiple service providers. Pairs of provider bridge networks may be interconnected on a 1:1 basis using bridges. However, these bridges are costly, and the number of bridges required to interconnect multiple service providers in a mesh increases exponentially relative to the number of service providers. Further, the frame replicators needed to connect a large number of points limits performance.
The problem is further exacerbated because multipoint connection circuits are becoming increasingly important in provider networks as providers deploy more diverse service offerings. Existing techniques for interconnection of provider bridged networks have poor scaling properties for multipoint connection circuits. This is in part due to the limits of current technologies which have difficulty scaling the number of replicator elements required to support traffic splitting for multipoint connections and the fact that the number of possible multipoint paths grows as 2**N, where N is the number of nodes.
SUMMARY OF THE INVENTIONIn accordance with one embodiment of the invention, apparatus for facilitating interconnection of a plurality of provider networks includes an edge device coupled between a backbone and a first one of the provider networks, the edge device being operable to encapsulate data units received from the first provider network with a header, and to forward the encapsulated data unit to the backbone, the header being indicative of a tunnel that is used to support traffic from the first provider network over the backbone.
In accordance with another embodiment of the invention, a method for facilitating interconnection of a plurality of provider networks includes the steps of: encapsulating, by an edge device, data units received from a first provider network with a header, the header being indicative of a tunnel that is used to support traffic from the first provider network over the backbone; and forwarding the encapsulated data unit to the backbone.
In accordance with another embodiment of the invention, a method for facilitating transporting a plurality of point-to-point, point-to-multipoint, and multi-point-to-multipoint connections over a carrier network includes the steps of: encapsulating, by an edge device data units received from a first provider bridge with a header, the header being indicative of a tunnel that is used to support traffic from point in the provider network to one or many other points in the provider network; and forwarding the encapsulated data unit.
One advantage of the invention is that the edge devices support hierarchical backbones that are readily scalable. In addition, the hierarchy created in the backbones creates relatively small multicast domains, each domain having a small number of bridges. With such an arrangement, the number of multipoint tunnels and replication is limited, and scaling is greatly improved.
Referring now to
Backbone Provider Bridge Edge (“BBPB”) devices (212, 214, 216, 218, 220, 222) facilitate operation of the B-VLANs and S-VLANs. Each PBN is associated with at least one BBPB device. Each BBPB is operable to encapsulate frames received from its associated PBN and destined for a different PBN. In particular, the BBPB encapsulates the frames in a data unit having a BPBN header. The BPBN header includes an Extended Service-VLAN Identifier (“ES-VID”) which identifies the S-VLAN associated with the PBN S-VIDs on the BPBN. The BPBN header also includes a Backbone-VLAN Identifier (“B-VID”). The B-VID identifies a Backbone VLAN tunnel that is used to transport the S-VLANs over the BPBN. B-VLAN tunnels can be point-to-point or multi-point in nature. Each BBPB is further operable to receive encapsulated frames from corresponding BBPBs associated with other PBNs. Upon receipt of an encapsulated frame from another PBN the BBPB is operative to de-encapsulate the frame by removing the BPBN header. The frame is then forwarded toward its destination in the target PBN.
Referring now to
In the case of the multi-layer hierarchy illustrated in
While the invention is described through the above exemplary embodiments, it will be understood by those of ordinary skill in the art that modification to and variation of the illustrated embodiments may be made without departing from the inventive concepts herein disclosed. Moreover, while the preferred embodiments are described in connection with various illustrative structures, one skilled in the art will recognize that the system may be embodied using a variety of specific structures. For example, the BPBN may be implemented with or without PBNs. Accordingly, the invention should not be viewed as limited except by the scope and spirit of the appended claims.
Claims
1. A method of interconnecting a first provider bridge network and a second provider bridge network, comprising:
- providing a backbone provider bridge network, the backbone provider bridge network comprising a first backbone provider bridge edge device for connection to the first provider bridge network and a second backbone provider bridge edge device for connection to the second provider bridge network, the first backbone provider bridge edge device being coupled to the second provider bridge edge device over the backbone provider bridge network; and
- configuring the first backbone provider bridge device: to receive a data unit from the first provider bridge network, the data unit having a header comprising a Service Virtual Local Area Network (S-VLAN) Identifier which is associated with the first and second provider bridge networks; to encapsulate the received data unit with a Backbone VLAN Identifier (B-VID) which is indicative of a backbone VLAN tunnel to be used to transport the S-VLAN over the backbone provider bridge network and an Extended S-VLAN Identifier (ES-VID) which is associated with the S-VLAN Identifier (S-VID); and to forward the encapsulated data unit over the backbone VLAN tunnel toward the second backbone provider bridge edge device.
2. The method of claim 1, further comprising forwarding the encapsulated data unit over the backbone VLAN tunnel toward the second backbone provider bridge edge device.
3. The method of claim 2, wherein:
- the backbone provider bridge network comprises a third backbone provider bridge edge device which is associated with the S-VLAN;
- the backbone VLAN tunnel is a point to multi-point tunnel linking the first backbone provider bridge edge device to the second and third backbone provider bridge edge devices; and
- forwarding the encapsulated data unit over the backbone VLAN tunnel comprises forwarding the encapsulated data unit over the backbone VLAN tunnel toward both the second and third backbone provider bridge edge devices.
4. The method of claim 1, comprising configuring the second backbone provider bridge edge device:
- to receive the encapsulated data unit forwarded from the first backbone provider bridge device;
- to decapsulate the encapsulated data unit by removing the B-VID; and
- to forward the decapsulated data unit to the second provider bridge network.
5. The method of claim 2, comprising:
- configuring the second backbone provider bridge edge device: to receive the encapsulated data unit forwarded from the first backbone provider bridge device; to decapsulate the encapsulated data unit by removing the B-VID; and to forward the decapsulated data unit to the second provider bridge network based on the S-VID; and
- forwarding the decapsulated data unit to the second provider bridge network.
6. The method of claim 1, comprising configuring the first backbone provider bridge edge device:
- to receive an encapsulated data unit forwarded from the second backbone provider bridge device, the encapsulated data unit having a header comprising the B-VID;
- to decapsulate the encapsulated data unit by removing the B-VID; and
- to forward the decapsulated data unit to the first provider bridge network.
7. The method of claim 2, comprising:
- configuring the first backbone provider bridge edge device: to receive an encapsulated data unit forwarded from the second backbone provider bridge device, the encapsulated data unit having a header comprising the B-VID; to decapsulate the encapsulated data unit by removing the B-VID; and to forward the decapsulated data unit to the first provider bridge network; and
- forwarding the decapsulated data unit to the first provider bridge network.
8. The method of claim 1, wherein configuring the first backbone provider bridge edge device to
- encapsulate the received data unit with an ES-VID comprises configuring the first backbone bridge device to replace the S-VID with the ES-VID and the B-VID.
9. The method of claim 5, wherein configuring the second backbone provider bridge edge device to decapsulate the encapsulated data unit comprises configuring the second backbone provider bridge edge device to replace the ES-VID and the B-VID with the S-VID.
10. The method of claim 6, wherein configuring the first backbone provider bridge edge device to decapsulate the encapsulated data unit comprises configuring the first backbone provider bridge edge device to replace the ES-VID and the B-VID with the S-VID.
11. The method of claim 1, wherein the backbone provider bridge network comprises:
- a first domain comprising the first backbone provider bridge edge device;
- a second domain comprising the second backbone provider bridge edge device; and
- a third domain comprising a third backbone provider bridge edge device coupled to the first domain and a fourth backbone provider bridge edge device coupled to the second domain, the fourth backbone provider bridge edge device being coupled over the third domain to the third backbone provider bridge edge device.
12. The method of claim 11, wherein:
- the first domain uses a first B-VID to forward data units over a tunnel in the first domain which is associated with the first and second provider bridge networks;
- the second domain uses a second B-VID to forward data units over a tunnel in the second domain which is associated with the first and second provider bridge networks; and
- the third domain uses a third B-VID to forward the data units over a tunnel in the third domain which is associated with the first and second provider bridge networks.
13. The method of claim 12, wherein the third backbone provider bridge edge device is configured to insert the third B-VID in data units received from the first domain having the first B-VID for forwarding of the received data units over the third domain.
14. The method of claim 13, wherein the third backbone provider bridge edge device is configured to insert the third B-VID in data units received from the first domain having the first B-VID by swapping the third B-VID for the first B-VID.
15. The method of claim 13, wherein the fourth backbone provider bridge edge device is configured to insert the second B-VID in received data units having the third B-VID for forwarding of the received data units over the second domain to the second backbone provider edge device.
16. The method of claim 15, wherein the fourth backbone provider bridge edge device is configured to insert the second B-VID in received data units having the third B-VID by swapping the second B-VID for the third B-VID.
17. The method of claim 1, wherein the backbone provider bridge network is a multi-layer hierarchical network.
18. The method of claim 17, comprising using B-VID swapping at boundaries between layers in the multilayer hierarchical network to forward data units over respective selected tunnels in the layers of the multilayer hierarchical network.
19. The method of claim 18, wherein B-VIDs are selected for data units received at boundaries between layers in the multi-layer hierarchical network based on ES-VIDs carried by the data units.
20. The method of claim 17, comprising B-VID stacking at boundaries between layers in the multi-layer hierarchical network to forward data units selectively over respective tunnels at each layer of the multilayer hierarchical network.
Type: Application
Filed: Sep 18, 2014
Publication Date: Jan 1, 2015
Applicant: ROCKSTAR CONSORTIUM US LP (Plano, TX)
Inventors: Paul Bottorff (Palo Alto, CA), Norival Figueira (Campbell, CA), Marc Holness (Ottawa)
Application Number: 14/489,625
International Classification: H04L 12/46 (20060101); H04L 12/24 (20060101);