CLIAMS:STATEMENT OF CLAIMS
We claim:
1. A method for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in an Ethernet network, the method comprising of an ingress device encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting a PBT Ethernet frame to an egress device, wherein the PBT Ethernet frame comprises the PBT Ethernet header.

2. The method, as claimed in claim 1, wherein the method further comprises of the ingress device encapsulating the at least one ISIS control packet using LLC-SNAP (Logical Link Control – Sub Network Access Protocol) encapsulation to form a LLC-SNAP encapsulation packet, before encapsulating the LLC-SNAP packet in the PBT Ethernet header.

3. The method, as claimed in claim 2, wherein the method further comprises of the ingress device setting ethertype-2 field in the PBT Ethernet header to to indicate presence of the at least one ISIS control packet in said PBT Ethernet header.

4. The method, as claimed in claim 1, wherein the method further comprises of
checking by the egress device if the at least one ISIS packet is present in the PBT Ethernet frame; and
sending the ISIS packet to ISIS by the egress device, if the at least one ISIS packet is present in the PBT Ethernet frame.

5. The method, as claimed in claim 4, wherein the method further comprises of checking by the egress device if the at least one ISIS packet is present in the PBT Ethernet frame by checking the ethertype-2 field in the PBT Ethernet header.

6. An Ethernet network configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network, the Ethernet network comprising of an ingress device encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting a PBT Ethernet frame to an egress device, wherein the PBT Ethernet frame comprises the PBT Ethernet header.

7. The Ethernet network, as claimed in claim 6, wherein the ingress device is further configured for encapsulating the at least one ISIS control packet using LLC-SNAP (Logical Link Control – Sub Network Access Protocol) encapsulation to form a LLC-SNAP encapsulation packet, before encapsulating the LLC-SNAP packet in the PBT Ethernet header

8. The Ethernet network, as claimed in claim 7, wherein the ingress device is further configured for setting ethertype-2 field in the PBT Ethernet header to to indicate presence of the at least one ISIS control packet in said PBT Ethernet header.
9. The Ethernet network, as claimed in claim 6, wherein the egress device is further configured for
checking if the at least one ISIS packet is present in the PBT Ethernet frame; and
sending the ISIS packet to ISIS, if the at least one ISIS packet is present in the PBT Ethernet frame.

10. The Ethernet network, as claimed in claim 9, wherein the egress device is further configured for checking if the at least one ISIS packet is present in the PBT Ethernet frame by checking the ethertype-2 field in PBT Ethernet header

11. An ingress device in a Ethernet network, wherein the Ethernet network is configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network, the ingress device configured for encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting a PBT Ethernet frame to an egress device, wherein the PBT Ethernet frame comprises the PBT Ethernet header.

12. The ingress device, as claimed in claim 11, wherein the ingress device is further configured for encapsulating the at least one ISIS control packet using LLC-SNAP (Logical Link Control – Sub Network Access Protocol) encapsulation to form a LLC-SNAP encapsulation packet, before encapsulating the LLC-SNAP packet in the PBT Ethernet header.

13. The ingress device, as claimed in claim 12, wherein the ingress device is further configured for setting ethertype-2 field in the PBT Ethernet header to to indicate presence of the at least one ISIS control packet in said PBT Ethernet frame.

14. An egress device in an Ethernet network, the Ethernet network configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network to the egress device from an ingress device, wherein the egress device is further configured for
checking if the at least one ISIS packet is present in a PBT Ethernet frame received from the ingress device, wherein the ingress device encapsulates the at least one ISIS control packet in a PBT Ethernet header before transmitting the PBT Ethernet frame to the egress device, wherein the PBT Ethernet frame comprises the PBT Ethernet header; and
sending the ISIS packet to ISIS, if the at least one ISIS packet is present in the PBT Ethernet frame.

15. The egress device, as claimed in claim 14, wherein the egress device is further configured for checking if the at least one ISIS packet is present in the PBT Ethernet frame by checking a ethertype-2 field in the PBT Ethernet header, wherein presence of in the ethertype-2 field indicates presence of the at least one ISIS control packet in said PBT Ethernet frame.

Date: 17th day of January, 2014 Signature:

Vikram Pratap Singh Thakur

Patent Agent
,TagSPECI:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“TRANSPORTING ISIS LLC-MAC FRAMES OVER PBT ETHERNET TUNNELS USING 802.1QAY”

APPLICANT:

Name : HCL Technologies Limited
Nationality : Indian
Address : HCL Technologies Ltd., 50-53 Greams
Road, Chennai – 600006, Tamil Nadu, India

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION
[001] This invention relates to communication networks, and more particularly to using Provider Backbone Transport (PBT) Ethernet tunnels to carry LLC-SNAP (Logical Link Control – Sub Network Access Protocol) headers comprising ISIS control packets.

BACKGROUND OF INVENTION
[002] Ethernet technology is used to enable devices to communicate over a Local Area Network (LAN) or a Wide Area Network (WAN). Ethernet based networks are widely prevalent in multiple industries, residential, commercial, retail and other areas.
[003] Provider Backbone Transport (PBT)/IEEE 802.1Qay enables use of existing Ethernet based networks to be used as a packet switch network technology. IEEE 802.1Qay specification specifies the mechanism to encapsulate and carry customer MAC (Media Access Control) frames over PBT Ethernet tunnels, mechanisms to carry customer frames inside PBT Ethernet header and mechanisms to carry Customer MAC frames which contain C-MAC addresses and ISID, thereby enabling the providers to establish point to point and point to multipoint Ethernet tunnels to carry traffic across an existing Ethernet based network. PBT combines MAC address and VLAN (Virtual Local Area Network) IDs to uniquely distinguish paths/tunnels across the network.
[004] The PBT Ethernet tunnels, which span across the Ethernet network, would be treated as a single IP hop by the IP/MPLS (Internet Protocol/Multiprotocol Label Switching) protocols within their topology. The IP/MPLS protocols are enabled on the devices at the edge of the Ethernet cloud and will be peering over the Ethernet network using the PBT Ethernet tunnels. Consider an example, where routing protocols such as ISIS (Intermediate System-to-Intermediate System) and so on have to operate their sessions across the PBT Ethernet tunnels. This requires the protocol specific control traffic to be carried across the PBT Ethernet tunnels. The protocol may specify that its control frames should be carried in LLC-SNAP (Logical Link Control – Sub Network Access Protocol) encapsulated format. However there is no mechanism to enable transport of LLC-SNAP encapsulated frames originated at the edge of the PBT cloud over the PBT Ethernet tunnels.

OBJECT OF INVENTION
[005] The principal object of this invention is to enable a mechanism to carry LLC-SNAP encapsulated frames originating at the edge of the PBT cloud over the PBT Ethernet tunnels.

STATEMENT OF INVENTION
[006] Accordingly the invention provides a method for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in an Ethernet network, the method comprising of an ingress device encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting the PBT Ethernet frame, wherein the PBT Ethernet frame comprises the PBT Ethernet header to an egress device.
[007] Provided herein is an Ethernet network configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network, the Ethernet network comprising of an ingress device encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting the PBT Ethernet frame, wherein the PBT Ethernet frame comprises the PBT Ethernet header to an egress device.
[008] Provided herein is an ingress device in a Ethernet network, wherein the Ethernet network is configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network, the ingress device configured for encapsulating the at least one ISIS control packet in a PBT Ethernet header before transmitting the PBT Ethernet frame, wherein the PBT Ethernet frame comprises the PBT Ethernet header to an egress device.
[009] Provided herein is an egress device in an Ethernet network, the Ethernet network configured for transmitting at least one ISIS (Intermediate System-to-Intermediate System) control packet over PBT (Provider Backbone Transport) Ethernet tunnels in the Ethernet network to the egress device from an ingress device, wherein the egress device is further configured for checking if the at least one ISIS packet is present in a PBT Ethernet frame, wherein the PBT Ethernet frame comprises the PBT Ethernet header received from the ingress device; and sending the ISIS packet to ISIS, if the at least one ISIS packet is present in the PBT Ethernet header.
[0010] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0011] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0012] FIG. 1a illustrates an Ethernet based network, according to embodiments as disclosed herein;
[0013] FIG. 1b illustrates an Ethernet ingress device and an Ethernet egress device connected by a PBT Ethernet tunnel, according to embodiments as disclosed herein;
[0014] FIG. 2 depicts a format of an PBT Ethernet header packet, wherein the header packet comprises of a LLC-SNAP encapsulated packet, according to embodiments as disclosed herein;
[0015] FIG. 3 depicts an Ethernet ingress device, according to embodiments as disclosed herein;
[0016] FIG. 4 depicts an Ethernet egress device, according to embodiments as disclosed herein;
[0017] FIG. 5 is a flowchart illustrating the process of communication which enables carrying of LLC-SNAP encapsulated frames over the PBT Ethernet tunnels, according to embodiments as disclosed herein;
[0018] FIG. 6 is a flowchart illustrating the process of transmitting a PBT Ethernet frame comprising a PBT Ethernet header, wherein the PBT Ethernet header comprises a LLC-SNAP encapsulated packet by an Ethernet ingress device, according to embodiments as disclosed herein; and
[0019] FIG. 7 is a flowchart illustrating the process of receiving a PBT Ethernet frame by an Ethernet egress device, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0020] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0021] The embodiments herein enable a mechanism to carry LLC-SNAP (Logical Link Control – Sub Network Access Protocol) encapsulated frames originating at the edge of the PBT (Provider Backbone Transport) cloud over the PBT Ethernet tunnels by carrying the LLC-SNAP frames as customer frames inside the PBT Ethernet header. Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0022] FIG. 1a illustrates an Ethernet based network, according to embodiments as disclosed herein. The network, as depicted herein, is merely depicted as an example and it may be obvious to a person of ordinary skill in the art to have any layout/topology for the Ethernet based network.
[0023] The Ethernet network, as depicted herein, comprises of a plurality of clients 101 connected to at least one switch 102. The at least one switch 102 may be connected to at least one router 103 directly or through at least one other switch 102. The router 103 may enable the clients 101 and/or switch 102 to connect to at least one other external entity. In an embodiment herein, the Ethernet network may comprise of a plurality of switches which support IEEE802.1Qay switching, wherein the plurality of switches form a PBT Ethernet cloud.
[0024] The client 101 may be a computing device (such as a computer, a laptop, a tablet, a server, a mobile device, a cellular device or any other device enabled to permit a user of the device to access a network), a printer, a scanner, a memory storage location, a database or any other device which is enabled to communicate over a network. The client 101, switch 102, the router 103 and the external entity may be connected using a suitable means such as a wired means or a wireless means. The external entity may be the internet, another network, a device and so on.
[0025] Any one of the devices (client 101, switch 102 and router 103) may interact with one another by a PBT Ethernet tunnel created between the communicating devices. The originating device may be referred to as an ingress device 104 and the destination device may be referred to as an egress device 105 (as depicted in FIG. 1b). The ingress device 104 and the egress device 105 may be connected by a point to point PBT Ethernet tunnel. The ingress device 104 and the egress device 105 may be connected by an indirect PBT Ethernet tunnel, which may be routed through at least one other device connected to the Ethernet.
[0026] In an embodiment herein, the PBT Ethernet cloud comprises of a plurality of switches all supporting Ethernet switching as defined in IEEE802.1Qay. A PBT Ethernet tunnel may be established across the PBT Ethernet cloud spanning the switches inside it. The packets which enter this tunnel would be encapsulated as per the PBT Ethernet header. The intervening switches in the path of the tunnel would switch based on the information present in the header.
[0027] IP/MPLS (Internet Protocol/Multiprotocol Label Switching) networks may be overlaid across a PBT Ethernet cloud formed across the entire Ethernet network or at least a portion of the Ethernet network. The Ethernet cloud connects the IP/MPLS networks. A suitable routing protocol may be used for routing in the IP/MPLS domain. The routing protocol would be peering across the Ethernet cloud, and would be treating PBT Ethernet tunnel as a single hop. In an embodiment herein, ISIS (Intermediate System-to-Intermediate System) may be used as a routing protocol in the IP/MPLS domain.
[0028] If a packet to be communicated is an ISIS control packet over a PBT Ethernet tunnel, the ingress device encapsulates the ISIS control packet as a LCC-SNAP encapsulated packet. The LCC-SNAP packet in turn is inserted in the PBT Ethernet header. The PBT Ethernet frame comprising the PBT Ethernet header is then transmitted to the egress device, over the Ethernet link. Ethernet switches present in the network may be used to switch the PBT Ethernet frame.
[0029] The egress device, on receiving the PBT frame, examines the LLC-SNAP encapsulated packet. Based on the information in the LLC-SNAP encapsulated packet, the egress device sends the packet to the ISIS.
[0030] FIG. 2 depicts a format of a PBT Ethernet header packet, wherein the header packet comprises of a LLC-SNAP encapsulated packet, according to embodiments as disclosed herein. The PBT Ethernet header comprises of the following fields: B-DMAC (Backbone Destination MAC address (6 bytes)) 201, B-SMAC (Backbone Source MAC address (6 bytes)) 202, B-VID (Backbone VLAN Identifier (2 bytes)) 204, ethertype1, ethertype2: (Type of traffic carried (2 bytes)) 203, 205, I-TAG (Instance Tag (4 bytes)) 206 and LLC-SNAP encapsulated packet 207.
[0031] The ether type2 field 205 comprises a TBD entry, wherein the TBD entry indicates that a LLC-SNAP encapsulated packet 207 is present in the PBT Ethernet frame.
[0032] FIG. 3 depicts an Ethernet ingress device, according to embodiments as disclosed herein. The Ethernet ingress device 104 may be any device capable of connecting to the Ethernet network and communicating using the Ethernet network such as an edge device. The Ethernet ingress device 104, as depicted, comprises of a controller 302, an encapsulation module 303 and a communication interface 304.
[0033] On detecting an ISIS control packet, the controller 302 forwards the ISIS control packet to the encapsulation module 303. The encapsulation module 303 encapsulates the ISIS control packet using LLC-SNAP encapsulation. The encapsulation module then determines the interface on which the packet is to be sent out, if the packet is to be sent out over a PBT Ethernet tunnel which is setup across the PBT Ethernet cloud, the controller 302 inserts the LLC-SNAP encapsulated packet into the PBT Ethernet header (as depicted in FIG. 2). The controller 302 also modifies the ethertype2 205 as , wherein the ethertype2 indicates that the presence of the LLC-SNAP encapsulated packet in the PBT Ethernet header. The controller 302 further transmits the PBT Ethernet frame using the communication interface 304.
[0034] FIG. 4 depicts an Ethernet egress device, according to embodiments as disclosed herein. The Ethernet egress device 105 may be any device capable of connecting to the Ethernet network and communicating using the Ethernet network such as an edge device. The Ethernet egress device 105, as depicted, comprises of a controller 402, a de-encapsulation module 403 and a communication interface 404.
[0035] On the Ethernet egress device 105 receiving a PBT Ethernet frame through the communication interface 404, the controller 402 invokes the de-encapsulation module 403. The de-encapsulation module 403 checks if the received PBT Ethernet header contains a LLC-SNAP encapsulation packet. The de-encapsulation module 403 checks if the received PBT Ethernet header contains a LLC-SNAP encapsulation packet by checking the ethertype-2 field 205. If the ethertype2 field 205 contains , then the de-encapsulation module 403 understands that an LLC-SNAP encapsulated packet is present in the PBT Ethernet header. The de-encapsulation module 403 inspects the LLC-SNAP packet. If the Ethernet LLC-SNAP encapsulation indicates that the packet is to be given to the ISIS, the de-encapsulation module 403 informs the same to the controller 402 and the controller 402 sends the packet to the ISIS.
[0036] FIG. 5 is a flowchart illustrating the process of communication which enables carrying of LLC-SNAP encapsulated frames over the PBT Ethernet tunnels, according to embodiments as disclosed herein. On receiving (501) an ISIS control packet, the ingress device 104 encapsulates (502) the ISIS control packet in the PBT Ethernet header as a LCC-SNAP encapsulated packet. The ingress device 104 transmits (503) the PBT Ethernet frame comprising the PBT Ethernet header to the egress device 105, over the intervening network of Ethernet switches. The egress device 105 receives (504) the PBT frame, examines the LLC-SNAP encapsulated packet. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.
[0037] FIG. 6 is a flowchart illustrating the process of transmitting a PBT Ethernet frame comprising a PBT Ethernet header, wherein the PBT Ethernet header comprises a LLC-SNAP encapsulated packet by an Ethernet ingress device, according to embodiments as disclosed herein. On receiving (601) a packet, the ingress device 104 checks (602) if the packet is an ISIS control packet. If the packet is not an ISIS control packet, the ingress device 104 proceeds (603) as for a normal packet. On detecting an ISIS control packet, the ingress device 104 encapsulates (604) the ISIS control packet using LLC-SNAP encapsulation. The ingress device 104 checks (605) if the packet is to be sent out over the PBT Ethernet tunnel. If the packet is not to be sent over the PBT Ethernet tunnel, the ingress device 104 proceeds (603) normally, If the packet is to be sent out over the PBT Ethernet tunnel, the ingress device 104 inserts (606) the LLC-SNAP encapsulated packet into the PBT Ethernet header (as depicted in FIG. 2). The source and destination MAC addresses in the PBT Ethernet header would be the MAC addresses of the ingress and egress devices. The ingress device 104 also modifies (607) the ethertype2 field 205 as , wherein the ethertype2 indicates the presence of the LLC-SNAP encapsulated packet in the PBT Ethernet header. The ingress device 104 further transmits (608) the PBT Ethernet frame comprising the PBT Ethernet header. The various actions in method 600 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 6 may be omitted.
[0038] FIG. 7 is a flowchart illustrating the process of receiving a PBT Ethernet frame by an Ethernet egress device, according to embodiments as disclosed herein. On the egress device 105 receiving (701) a PBT Ethernet frame comprising the PBT Ethernet header through the communication interface 404, the egress device 105 checks (702) if the received PBT Ethernet header contains a LLC-SNAP encapsulation packet by checking if the ethertype2 field 205 contains . If the received PBT Ethernet header does not contain a LLC-SNAP encapsulated packet, the egress device 105 processes (703) the PBT Ethernet header normally. If the ethertype2 field indicates presence of a LLC-SNAP Ethernet header, the egress device 105 inspects (704) the LLC-SNAP packet. If the Ethernet LLC SNAP encapsulation indicates that the frame is meant for the local ISIS, the egress device 105 sends (705) the packet to the ISIS. The various actions in method 700 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 7 may be omitted.
[0039] Embodiments disclosed herein enable ISIS control packets to be sent over PBT Ethernet tunnels. This is an efficient way of interconnecting IP/MPLS networks across the PBT Ethernet cloud. IP/MPLS networks may be overlaid across a PBT Ethernet cloud and the Ethernet cloud would be interconnecting the IP/MPLS network elements. In this case, ISIS may be used as a routing protocol in the IP/MPLS domain. ISIS would be peering across the Ethernet cloud. ISIS may be running on the devices at the ends of the PBT Ethernet tunnel and may be treating the tunnel as a single hop from the routing perspective.
[0040] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in Figs. 1, 3 and 4 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0041] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.



ABSTRACT

Transporting ISIS LLC-MAC Frames over PBT Ethernet Tunnels using 802.1Qay. This invention relates to communication networks, and more particularly to using Provider Backbone Transport (PBT) Ethernet tunnels to carry LLC-SNAP (Logical Link Control – Sub Network Access Protocol) headers comprising ISIS control packets.

FIG. 2