Patent Application
20070153799
The present invention relates to communicating over networks having different identification schemes.
DSL (Digital Subscriber Line) services are conventionally provided over ATM (Asynchronous Transfer Mode) networks and may be managed on a per-service and a per-customer basis. For example, each service is assigned a VPI (Virtual Path Identifier) and for each VPI, there is a list of customers, each customer being assigned a VCI (Virtual Circuit Identifier). Examples of services include, but are not limited to, Internet services, video, audio, television, and VoIP (Voice over Internet Protocol).
An example of an ATM DSL services solution is shown in
In the example of
Traffic in an Ethernet is identified by a VLAN (Virtual Local Area Network) identifier or tag in the header of an Ethernet frame. A standard Ethernet frame can include stacked VLAN tags.
Hybrid networks comprised of two or more networks that identify traffic using different protocols also exist. For example, a hybrid network may be made up of an ATM network and an Ethernet. Another example of a hybrid network is a network comprised of an MPLS (Multiple Protocol Labelling System) network and an Ethernet. Any combination of ATM, Ethernet, IP (Internet Protocol), MPLS, etc may make up a hybrid network.
In one aspect of the present invention, there is provided a method of identifying traffic in a hybrid network, the hybrid network comprising two or more networks having different schemes for identifying traffic on two or more levels, the method comprising: mapping, at each level, the identifiers for identifying traffic in one network to identifiers for identifying traffic in an other network.
In another aspect of the present invention, there is provided a computer readable medium having computer readable instructions stored thereon that when executed by a computer implement any of the methods described herein.
In another aspect of the present invention, there is provided an apparatus for mapping traffic identifiers in a hybrid network, the hybrid network comprising two or more networks having different schemes for identifying traffic on two or more levels, the apparatus comprising: an input module for receiving identifiers for identifying traffic on two or more levels for one of the networks; a mapping module for creating a map which for each level of identifier, maps the identifiers received to identifiers for another network.
Embodiments of the present invention enable traffic in a hybrid network to be identified on two or more levels in a uniform manner, regardless of the identification scheme of the various networks that make up the hybrid network. For example, in a hybrid network comprised of an ATM network and an Ethernet, DSL traffic within the ATM network can be identified by VPI/VCI at the service provider end. The VPI/VCI DSL traffic directed to customers over the Ethernet will be mapped to a two level VLAN identifier. For example, the VLAN identifier could be comprised of an S-VLAN/C-VLAN identifier (where S is for service, and C is for customer).
Other aspects and features of the present invention will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific exemplary embodiments of the invention.
Exemplary embodiments of the invention will now be described in greater detail with reference to the accompanying drawings, in which:
Throughout this description, the expressions “map”, “mapped” and “mapping” are used to refer to any association, allocation or assignment of one identifier to another identifier.
An ATM DSLAM to Ethernet DSLAM migration scenario according to one embodiment of the present invention is shown in
In some embodiments the Ethernet 240 is a metro Ethernet. In some embodiments, the Ethernet DSLAM 250 is an IP DSLAM. Examples of the interworking network element 230 include a node, switch, router, switch/router, as well as other network elements.
For ease of management and deployment it is desirable to keep the same paradigm as all ATM DSL solutions with respect to connection management and customer provisioning, such where the service type is identified with a VPI and the customer is identified with a VCI. To that end, some embodiments of the present invention use stacked VLAN tags with one VLAN ID for each service type (S-VLAN) and another for each customer (C-VLAN). In embodiments where Ethernet frames allocate 12 bits to VLAN IDs, the maximum number of C-VLANs per S-VLAN will be approximately 4,000. The interworking network element 230 has access to a map 235 which maps data packets received from one VPI/VCI to the appropriate S-VLAN/C-VLAN, and vice versa. For example, data packets of VPI2/VCI1 would be mapped to S-VLAN1/C-VLAN1. In some embodiments the map 235 is maintained on the interworking network element 230. The map 235 is updated with the addition and removal of services and DSLAMs.
For PVP in the embodiment of
EP1=1-3-1-1; VPI2
EP2=1-5-1-1; V1
#cust=100
#starting VCI=32
In this example, 1-3-1-1 is a port number for endpoint EP1, VPI2 is a VPI number for endpoint EP1, 1-5-1-1 is a port number for endpoint EP2, and V1 is a VLAN ID for EP2. Then a mapping table is automatically generated for mapping 100 C-VLANs for S-VLAN1 to 100 VCIs, starting at VCI32 for VPI2.
In another approach, destination configuration endpoints are added to the network. For example they can be added to the network 200 described with reference to
EP3=1-5-1-1; V5
# customer=X
# starting VCI=Y
In this case a mapping table is generated at the interworking network element mapping X VCIs starting at VCI Y to X C-VLAN IDs for EP3.
An advantage of using destination configuration endpoints is that the provisioning of an S-PVP can be changed without affecting services carried on it. For example, another set of VCIs for new customers can be added to the S-PVP by provisioning at the destination configuration endpoint. Furthermore, it is unnecessary to change the signalling protocol.
In other cases, extra information is embedded in the signalling. IEs (Information Elements) can be modified or new IEs can be added. In some cases, new IEs are used in conjunction with, for example, the PNNI modify request message. This technique does not require connect/re-connect actions which would be service affecting in order to implement provisioning changes to S-PVPs. Adding new IEs would require modifications to the standards. For instance, Generic Identifier Transport (GIT) information element may be used to describe the correlation of mapping between VCI and C-VLAN in the interworking node as the destination node.
Embodiments of the present invention are applicable to interworking other types of dissimilar networks, such as MPLS and Ethernet for the purposes of providing DSL services. In these cases, the general concept is the same. Hierarchical VLAN IDs for identifying traffic of the Ethernet on a per-service and per-customer basis are provided and then mapped at an interworking network element between the networks to a corresponding hierarchical arrangement of connections or pseudo-wire connections.
One embodiment of the invention provides mapping of VPI to PW label at PE1. The PW label is used across the MPLS network 310 and the VCI is carried across the MPLS network 310. Then at PE2, the PW label is mapped to a S-VLAN and the VCI is mapped to a C-VLAN to produce a map 335 from MPLS/ATM identifiers to Ethernet identifiers for the customers. In this case the sequence of mapping is: VPI/VCI=>PW label/VCI=>S-VLAN/C-VLAN.
Another embodiment is adapted to provide a mapping of VCI to C-VLAN at PE1, in addition to the mapping of VPI to PW label. Then at PES the PW label can be mapped to a S-VLAN. In this embodiment, the sequence of mapping is: VPI/VCI=>PW label/C-VLAN=>S-VLAN/C-VLAN.
In another embodiment of the present invention, an Ethernet VLAN BRAS is used and an MPLS network interconnects the BRAS and an Ethernet network. There are two PEs: one between the BRAS and MPLS network and another one between MPLS Network and Metro-Ethernet network. In this case, an S-VLAN facing the Ethernet VLAN BRAS and an S-VLAN facing the Ethernet network are connected as an ethernet pseudo-wire. In the MPLS network, there are three MPLS labels: 1) the outer label corresponding to a tunnel LSP, 2) the first inner label corresponding to the S-VLAN and 3) the second inner (innermost) label corresponding to the C-VLAN. The two PEs perform mapping of the inner label to S-VLAN and mapping of the innermost label to the C-VLAN in similar manner as VCI-C-VLAN mapping described with reference to
In some embodiments, one level of the identifiers of at least one of the networks identifies a service type of the traffic. In some cases, one level of the identifiers of at least one of the networks identifies a customer.
In some embodiments, one level of the identifiers of at least one of the networks is mapped to a VPI (Virtual Path Identifier) in another network. In some cases, the VPI represent a service type. Types of service include, but are not limited to internet service, video, television, audio, and VoIP.
In some embodiments, one level of the identifiers of at least one of the networks is mapped to a VCI (Virtual Circuit Identifier) in another network. In some cases, the VCI represents a customer.
In some embodiments, in each network, one level of identifiers is a subset of another level of identifiers. In some embodiments, the Ethernet identifiers are VLAN IDs (Virtual Local Area Network Identifiers) stacked in Ethernet frames.
Methods in accordance with embodiments of the present invention can be implemented on any hybrid network. In exemplary embodiments, the networks making up the hybrid network are selected from the group consisting of: an ATM (Asynchronous Transfer Mode) network; an Ethernet; an IP (Internet Protocol) network; a VLAN (Virtual Local Area Network); and an MPLS (Multiple Protocol Labelling System) network.
In a preferred embodiment, the method is applied to DSL subscriber access. In such a case, the traffic is DSL traffic. However, embodiments of the present invention are not limited to DSL subscriber access. Other types of subscriber access include, but are not limited to digital cable, and wireless communications.
The methods of embodiments of the present invention can be implemented in hardware, software or combination thereof. Some embodiments comprise a computer readable medium having computer readable instructions stored thereon that when executed by a computer implement any of the methods described herein.
In some embodiments, the apparatus 700, further comprises an identifier creation module for creating identifiers on two or more levels for traffic in the other network.
In some embodiments, the apparatus further comprises an output module for outputting the map to a user interface. In some embodiments, the apparatus 700, further comprises the user interface.
In some embodiments, the apparatus 700, further comprises a switching module for directing traffic according to the identifiers of either of the networks.
In some embodiments, the mapping module 720 maps VPIs and VCIs from an ATM to stacked VLAN (Virtual Local Area Network) identifiers for an Ethernet.
The map 800 is stored on a machine readable storage medium and accessible by a network element that must direct traffic from one network to another. Examples of such an interworking network element are described with reference to
What has been described is merely illustrative of the application of the principles of the invention. Other arrangements and methods can be implemented by those skilled in the art without departing from the spirit and scope of the present invention.
