Patent Application
20070286207
The features and advantages of the invention will become more apparent from the following detailed description of the preferred embodiment(s) with reference to the attached figures, wherein:
It is noted that in the attached figures, like features bear similar labels.
Referring to
The hybrid IP/ATM NT 100 has an ATM network interface 119 connected to an ATM uplink 102 such as an OC12, OC3, DS3, or DS1. The ATM network interface 119 is coupled to an ATM switch 112 on the hybrid IP/ATM NT 100. The ATM switch 112 is coupled to an ATM bus interface 113 which is connected to an ATM bus 202. The ATM switch 112 is coupled over an ATM switch control line 115 to an ATM OBC 114 of the hybrid IP/ATM NT 100. The ATM switch 112 is coupled by an ATM connection 116 to an inter-working function (IWF) element 130. The IWF element 130 could be a network processor element typically used in existing GigE/IP LT cards to recast ATM streams into GigE/IP streams and to recast GigE/IP streams into ATM streams. It follows therefore that in some embodiments the IWF element 130 can be made using existing designs for hardware typically used elsewhere.
The hybrid IP/ATM NT 100 has a GigE/IP network interface 129 connected to GigE/IP uplinks 104. The GigE/IP network interface 129 is coupled to a GigE/IP switch 122 on the hybrid IP/ATM NT 100. The GigE/IP switch 122 is coupled to a GigE/IP bus interface 123 which is connected to a GigE/IP star bus 222. The GigE/IP switch 122 is coupled by a GigE/IP connection 126 to the IWF element 130. The GigE/IP switch 122 is coupled over a GigE/IP switch control line 125 to a GigE/IP OBC 124.
The ATM OBC 114, the ATM switch control line 115, the ATM switch 112, the ATM network interface 119, the ATM bus interface 113, and an interface 2 for shared resources are collectively referred to as the ATM NT module 110 of the hybrid IP/ATM NT 100. The ATM NT module 110 is connected via an ATM bus 202 to ATM LT cards 200 and via the ATM extension chain 204 to other ATM devices if any. The ATM LT cards 200 are standard ATM LT cards that could be used in known ATM DSLAMs. Here they are shown connected by the ATM bus 202 to the ATM bus interface 113 of the hybrid IP/ATM NT 100 and may form part of a hybrid IP/ATM DSLAM.
The GigE/IP OBC 124, the GigE/IP switch control line 125, the GigE/IP switch 122, the GigE/IP network interface 129, an interface 3 for shared resources, and the GigE/IP bus interface 123 are collectively referred to as the GigE/IP NT module 120 of the hybrid IP/ATM NT 100. The GigE/IP NT module 120 is connected over a GigE/IP star bus 222 to GigE/IP LTs 220. The GigE/IP NT module 120 is designed to work with GigE/IP interfaces and hence existing network equipment based on ATM technology are used with the ATM NT module 110. The GigE/IP LT cards 220 are standard GigE/IP LT cards that could be used in known GigE/IP DSLAMs. Here they are shown connected by the GigE/IP star bus 222 to the GigE/IP bus interface 123 of the hybrid IP/ATM NT 100 card and may form part of a hybrid IP/ATM DSLAM.
Collectively the GigE/IP switch 122, GigE/IP connection 126, the IWF element 130, the ATM connection 116, and the ATM switch 112 are referred to as an IP/ATM bridge 105. The GigE/IP NT module 120 is therefore understood to be coupled by the IP/ATM bridge 105 to the ATM NT module 110.
An NT card in a known DSLAM will typically have interfaces to resources including other cards, the backplane of the DSLAM, and external peripherals associated with the DSLAM. In an ATM DSLAM the ATM NT card would have these interfaces, while in a GigE/IP DSLAM the GigE/IP NT card would have these interfaces. To avoid duplication of all the resources interfaced with the hybrid IP/ATM NT card 100, the ATM NT module 110 and the GigE/IP NT module 120 of the hybrid IP/ATM NT 100 card share these resources. A shared resource is connected to the hybrid IP/ATM NT 100 at a single resource interface 10 of a resource sharing switch multiplexer 5. The resource sharing switch multiplexer 5 has a first access interface 4 connected to an interface 2 of the ATM NT module 110. The resource sharing switch multiplexer 5 also has a second access interface 6 connected to an interface 3 of the GigE/IP NT module 120. A control input 7 to the resource sharing switch multiplexer 5 is coupled to a resource sharing controller 8.
The hybrid IP/ATM NT 100 shown in
The ATM NT module 110 functions as an ATM NT providing ATM network termination and control functionality with an ATM aggregation uplink. The ATM NT module 110 is designed to work with ATM interfaces and supports existing xDSL services to end users such as HSI over ADSL by multiplexing ATM traffic over the ATM bus 202 to and from the ATM LT cards 200. The ATM NT module 110 communicates with the network over its ATM network interface 119 to uplink 102 using OC12, OC3, DS3, and DS1, and others. The hybrid IP/ATM NT 100 is capable of communicating with existing ATM based hardware such as existing ATM LT cards, and provides support for existing ATM system interfaces such as the ATM network interface 119. The ATM NT module 110 has its own independent central processing unit (ATM OBC 114) and provides ATM network termination. The ATM NT module 110 also takes care of the management of the ATM LT cards 200 over the ATM bus 202. As such, the ATM NT module 110 of the hybrid IP/ATM NT 100 provides all of the functions of a known ATM NT so that the hybrid IP/ATM NT 100 is compatible with ATM network infrastructure allowing continued use of existing ATM hardware such as racks, shelves, and ATM LT cards from existing ATM DSLAMs. The ATM OBC 114 performs the necessary control functions for the ATM NT module 110 including controlling the ATM switch 112 by transmitting control commands over the ATM switch control line 115, and managing the ATM LT cards 200 over the ATM bus 202.
The GigE/IP NT module 120 functions as a GigE/IP NT providing GigE/IP network termination and control functionality with GigE/IP aggregation. The GigE/IP NT module 120 provides more bandwidth both on its GigE/IP network interface 129 and through its GigE/IP bus interface 123, over the GigE/IP star bus 222 and to the GigE/IP LT cards 220 than the ATM NT module 110 does on its ATM network interface 119 and through its ATM bus interface 113 over the ATM bus 202 to the ATM LT cards 200. The GigE/IP NT module 120 takes part in the provision of more enhanced features in comparison to the ATM NT module 110. Since the GigE/IP NT module 120 has a GigE/IP network interface for interfacing with multiple GigE/IP uplinks 104 towards the network, it can provide over high speed DSL such as SHDSL and VDSL, very high speed services such as Video, Voice, VoIP, IPTV, and HSI to end customers and allows for such capabilities as TV broadcasting using phone lines. The GigE/IP NT module 120 is designed to work with GigE/IP interfaces, and communicates with the network over its GigE/IP based GigE/IP network interfaces 129. The GigE/IP NT module 120 serves end users by multiplexing network traffic over the GigE/IP star bus 222 to and from the GigE/IP LT cards 220. The hybrid IP/ATM NT 100 is capable of communicating with existing GigE/IP based hardware such as GigE/IP LT line cards, and provides support for existing GigE/IP system interfaces for connecting to the GigE/IP uplinks 104. The GigE/IP NT module 120 has an Ethernet-based switching core (GigE/IP switch 122) with per-slot connectivity at GigE rate and has its own central processing unit (GigE/IP OBC 124) and performs GigE/IP EMAN (Ethernet Metro Area Network) network termination. The GigE/IP NT module 120 also takes care of the management of the GigE/IP LT cards 220 over the GigE/IP star bus 222. As such, the GigE/IP NT module 120 of the hybrid IP/ATM NT 100 provides all of the functions of a known GigE/IP NT so that the hybrid IP/ATM NT 100 can bring GigE/IP functionality to an ATM infrastructure, the hybrid IP/ATM NT 100 being compatible with ATM style racks, shelves, alarm monitoring systems, and other support systems. The GigE/IP OBC 124 performs the necessary control functions for the GigE/IP NT module 120 including controlling the GigE/IP switch 122 by transmitting control commands over the GigE/IP switch control line 125 and managing the GigE/IP LT cards 220 over GigE/IP bus 222.
The GigE/IP NT module 120 and the ATM NT module 110 act independently of one another with the exception of some shared functions including backplane signaling and with the exception of their passing data between each other using the IP/ATM bridge 105.
The IP/ATM bridge 105 serves to pass or cross over network traffic from the GigE/IP NT module 120 to the ATM NT module 110 and from the ATM NT module 110 to the GigE/IP NT module 120. Network traffic that has crossed over the IP/ATM bridge 105 is hereinafter referred to as crossover traffic.
In the upstream direction from the ATM NT module 110 to the GigE/IP NT module 120, traffic traverses from ATM LT cards 200 over the ATM bus 202 to the ATM bus interface 113 of the ATM NT module 110 as ATM traffic. The ATM traffic enters the ATM switch 112 which routes the ATM traffic over the ATM connection 116 to the IWF element 130. The IWF element 130 serves to recast the ATM traffic in the form of an ATM data stream into a GigE/IP data stream generating crossover GigE/IP traffic. In the particular implementation of the preferred embodiment this recasting is carried out by extracting the payload and VPI/VCI (virtual path identifier/virtual channel identifier) identifier from the ATM cells of the ATM data stream, finding in a look-up table the VLAN ID corresponding to the VPI/VCI, and finally inserting the payload into Ethernet packets of the GigE/IP data stream ensuring they are tagged with the corresponding VLAN ID. The crossover GigE/IP traffic traverses the GigE/IP connection 126 to the GigE/IP switch 122 of the GigE/IP NT module 120 where it is routed through the GigE/IP network interface 129 and over appropriate upstream GigE/IP uplinks 104.
In the upstream direction from the GigE/IP NT module 120 to the ATM NT module 110, traffic traverses from the GigE/IP LT cards 220 over the GigE/IP star bus 222 through the GigE/IP bus interface 123 of the GigE/IP NT module 120 to the GigE/IP switch 122 as GigE/IP traffic. The GigE/IP switch 122 routes the GigE/IP traffic over the GigE/IP connection 126 to the IWF element 130. The IWF element 130 serves to recast the GigE/IP traffic in the form of a GigE/IP data stream into an ATM data stream generating crossover ATM traffic. In the particular implementation of the preferred embodiment this recasting is carried out by extracting the payload and VLAN ID from the Ethernet packets of the GigE/IP data stream, finding in a look-up table the VPI/VCI identifier corresponding to the VLAN ID, and finally inserting the payload into ATM cells of the ATM data stream ensuring they have the corresponding VPI/VCI identifier. The crossover ATM traffic traverses the ATM connection 116 to the ATM NT module 110 at the ATM switch 112 where it is routed through the ATM network interface 119 and over the upstream ATM uplink 102.
In the downstream direction from the GigE/IP NT module 120 to the ATM NT module 110, GigE/IP traffic from the upstream network from the GigE/IP uplinks 104 traverses through the GigE/IP network interface 129 to the GigE/IP switch 122 where it is routed over the GigE/IP connection 126 to the IWF element 130. As discussed above, the IWF element 130 serves to recast the GigE/IP traffic in the form of a GigE/IP data stream, while ensuring a desired VLAN ID to VPI/VCI mapping, into an ATM data stream generating crossover ATM traffic. The crossover ATM traffic traverses the ATM connection 116 to the ATM switch 112 of the ATM NT module 110 which routes the crossover ATM traffic through the ATM bus interface 113 and over the ATM bus 202 to the ATM LT cards 200.
In the downstream direction from the ATM NT module 110 to the GigE/IP NT module 120, ATM traffic from the upstream network emerges from the ATM uplink 102 through the ATM network interface 119 and to the ATM switch 112 where it is routed over the ATM connection 116 to the IWF element 130. As discussed above, the IWF element 130 serves to recast the ATM traffic in the form of an ATM data stream, while ensuring a desired VPI/VCI to VLAN ID mapping, into a GigE/IP data stream generating crossover GigE/IP traffic. The crossover GigE/IP traffic traverses the GigE/IP connection 126 to the GigE/IP NT module 120 at the GigE/IP switch 122 which routes the crossover GigE/IP traffic through the GigE/IP bus interface 123 and over the GigE/IP star bus 222 to the GigE/IP LT cards 220.
The hybrid IP/ATM NT 100 by including an ATM NT module 110 and a GigE/IP NT module 120 provides an upgrade path from the ATM DSLAM platform to the GigE/IP DSLAM platform. Preferably, the IP/ATM NT 100 is housed in a DSLAM having slots in each shelf capable of supporting both types of line interface module, namely both ATM LTs and GigE/IP LTs.
The hybrid IP/ATM NT 100 extends the functionality of network termination cards to allow for simultaneous termination of two traffic types, ATM and GigE/IP.
Although all four possibilities for traffic flow have been described, subscribers on the GigE/IP LTs would typically only be connected to the network through the GigE/IP uplinks 104 due to the bandwidth bottle neck of the ATM uplink 102. Although subscribers on the ATM LTs could be connected to the network through the ATM uplink 102, they also could take advantage of the GigE/IP uplinks 104 via the IP/ATM bridge's IWF element 130 between the GigE/IP NT module 120 and the ATM NT module 110. Due to the relatively larger bandwidth of the GigE/IP uplinks 104, they do not act as a bottle neck for service to the ATM LT subscriber.
Since the hybrid IP/ATM NT 100 has a GigE/IP NT module 120 and an ATM NT module 110, the software to run the hybrid IP/ATM NT 100 may in fact be made up of two separate software entities to run these modules. The software entities could be completely independent of each other and could be completely separate software loads allowing for individual replacement, reset, or upgrade of one software entity without affecting the other software entity.
In the preferred embodiment the GigE/IP LTs 220 are controlled by software on the GigE/IP NT module 120 and the ATM LTs 200 are controlled by software on the ATM NT module 110.
One of the benefits of the hybrid IP/ATM NT 100 is its ability to be incorporated into a network infrastructure without requiring fundamental changes to existing external management strategies.
An external management system, such as an NMS (network management system), can present an integrated view of the system including the hybrid IP/ATM NT 100. Each of the GigE/IP NT module 120 and the ATM NT module 110 has its own separate management interface including a separate external IP address, a separate SNMP agent, and so on. This allows for the GigE/IP NT module 120 and the ATM NT module 110 to have separate network IDs, to be managed separately, and also to report their own alarms independently and separately.
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In general sharing of resources by the GigE/IP NT module 120 and the ATM NT module 110 is provided through the use of the resource sharing switch multiplexer 5. Signals over the control input 7 to the resource sharing switch multiplexer 5 from the resource sharing controller 8 determine which of the GigE/IP NT module 120 and the ATM NT module 110 has access to or is interfaced with the shared resource. The resource sharing controller 8 may be part of the GigE/IP NT module 120, or may be part of the ATM NT module 110, and particularly could be the GigE/IP OBC 124 or the ATM OBC 114 respectively. The resource sharing controller 8 could also be a third party or component.
An example resource shared by the GigE/IP NT module 120 and the ATM NT module 110 is an alarm card installed in the hybrid DSLAM. In this particular implementation the interfaces 2, 4, 3, 6, and 10 are all interfaces appropriate for the alarm card. The resource sharing switch controller 8 could be implemented by a semaphore set to cause the resource sharing switch multiplexer 5 to switch to the appropriate access interface 6, 4 to allow access by the GigE/IP NT module 120 or the ATM NT module 110. The semaphore could be set by a third party, by one or both of the GigE/IP OBC 124 and the ATM OBC 114.
Another example resource shared by the GigE/IP NT module 120 and the ATM NT module 110 is an interface to an external dumb terminal having a serial interface. In this particular implementation the resource sharing controller 8 snoops input from the dumb terminal entering the single resource interface 10 of the resource sharing switch multiplexer 5. When a particular control character input is detected by the resource sharing controller 8, the resource sharing controller 8 switches the resource sharing switch multiplexer 5 to the first access interface 4 to give access to the ATM NT module interface 2, and when a different particular control character input is detected by the resource sharing controller 8, the resource sharing controller 8 switches the resource sharing switch multiplexer 5 to the second access interface 6 to give access to the GigE/IP NT module interface 3. In some particular implementations, the resource sharing switch multiplexer 5 and the resource sharing controller 8 performing the snooping of the single resource interface 10 may be implemented on one of the GigE/IP NT module 120 and the ATM NT module 110.
Another example resource shared by the GigE/IP NT module 120 and the ATM NT module 110 is an Ethernet interface to, for example, a LAN having a first entity communicating with the ATM NT module 110 and a second entity communicating with the GigE/IP NT module 120. In this particular embodiment, the resource sharing controller 8 and the resource sharing switch multiplexer 5 are embodied in a single Ethernet switch. In this case the Ethernet switch would perform soft switching to ensure proper delivery of Ethernet packets to and from the ATM and GigE/IP NT modules 110, 120 and the first and second entities in the LAN.
Another example shared resource is an activity latch, typically used for setting activity of each of a pair of known NT cards. In the preferred embodiment of the hybrid IP/ATM NT 100, the card may function in duplex mode (two card configuration) or in simplex mode (a single card configuration). In duplex mode activity should only be requested from the activity latch for the hybrid IP/ATM NT 100 card if both the GigE/IP NT module 120 and the ATM NT module 110 are functioning and both requesting activity. In this case the request for activity binary signal from each of the GigE/IP NT module 110 and the ATM NT module 110 is interfaced into the resource sharing switch multiplexer 5. The resource sharing controller 8 snoops the request for activity from each of the ATM NT module 110 and the GigE/IP NT module 120. The resource sharing controller 8 is such that only when both requests for activity are present is a request for activity sent out of the single resource interface 10. In other embodiments the resource sharing switch multiplexer 5, and resource sharing controller 8 are combined into a series of logic gates which transmit a high signal over the single resource interface 10, only when both the GigE/IP NT module 120 and the ATM NT module 110 are requesting activity. In simplex mode, activity should be requested from the activity latch for the hybrid IP/ATM NT 100 card as long as either one of the GigE/IP NT module 120 and the ATM NT module 110 is functioning and requesting activity. In this mode the resource sharing controller 8 is such that when either request for activity is present, a request for activity is sent out of the single resource interface 10.
It should be understood that there are numerous implementations and variations for configuring resource sharing for the ATM NT module 110 and the GigE/IP NT module 120. Interfaces can be switched in response to internal, external, or third party control, and can be arranged for an interface which mostly receives input or for an interface which mostly sends output. Although only one shared resource, a single switch multiplexer 5, and a single shared resource controller 8 have been discussed, it should be understood that any number of different resources may be shared between the ATM NT module 110 and the GigE/IP NT module 120, as long as the hybrid IP/ATM NT 100 has the requisite number of switch multiplexers 5 and resource sharing controllers 8 and associated links and interfaces. In general any interface typically on an ATM NT card or a GigE/IP card can be shared between the ATM NT module 110 and the GigE/IP NT module 120 in similar manner to that of the preferred embodiment as discussed above.
Service providers looking to replace their large investment in existing ATM DSLAMs and ATM network infrastructure with GigE/IP DSLAMs and GigE/IP infrastructure are finding it difficult to switch due to the amount of the existing equipment and the cost that such a migration from ATM to GigE/IP entails.
A migration path from ATM DSLAMs to GigE/IP DSLAMs which allows for gradual introduction and switching from the old ATM equipment to new GigE/IP based equipment is preferred as part of a DSL services migration from an ATM network infrastructure to a GigE/IP network infrastructure.
Service providers can use the hybrid IP/ATM NT 100 as part of such a migration path from ATM DSLAMs to GigE/IP DSLAMs by providing a DSLAM with hybrid IP/ATM capability. The hybrid IP/ATM NT 100 immediately brings GigE/IP NT capabilities and support for GigE/IP LT line cards to an ATM infrastructure, while providing for gradual migration to a GigE/IP network infrastructure by allowing customers to re-use their existing ATM DSLAM infrastructure while replacing existing ATM DSLAMs. As hybrid IP/ATM NTs 100 are introduced into the ATM network infrastructure, existing ATM hardware, services, and system interfaces can be re-used with the hybrid IP/ATM NT 100 while new GigE/IP DSLAM capabilities are introduced into the network infrastructure. In this manner service providers can plan to integrate the GigE/IP based network topology into their networks without throwing away existing ATM based network topology. Most of the heavily deployed ATM based ATM DSLAM equipment may be re-used during the introduction of next generation GigE/IP DSLAM capabilities avoiding the large economical burden that would be associated with a massive decommissioning of ATM network infrastructure resources and the simultaneous deployment of all new GigE/IP based network infrastructure.
Some of the benefits of a hybrid IP/ATM NT 100 include its greater bandwidth support for GigE/IP LTs ( 1 Gig per LT), its simultaneous dual circuit and packet operation, its usefulness in providing a customer controlled. transition timeline from ATM to Ethernet, its preservation of the current ATM DSLAM installed base to reduce transition costs and its ability to maintain current ATM installations, ATM interfaces, and ATM connection provisioning for existing subscribers with its ATM capabilities. It allows for the existing ATM interfaces to be maintained as the various types of interfaces are supported by the hybrid NT. Deployed ATM systems can be upgraded with GigE/IP and high bandwidth fabric provided by the hybrid IP/ATM NT 100.
On the GigE/IP side the hybrid IP/ATM NT 100 supports the existing BRAS (broadband remote access server) based connection model for both HSI and IP Video subscribers, while enabling IPTV service for new and migrated subscribers. The hybrid IP/ATM NT 100 supports non-blocking aggregation/subscriber traffic via Gigabit Ethernet interfaces, provides additional GigE/IP Interfaces for new IPTV subscribers, and is full line rate capable and compatible with 1000 Base SX,LX and TX via Small Form-factor Pluggable (SFP) modules.
In general network service providers benefit from the ability to leverage deployed platforms and minimize operational discontinuities in the migration from ATM to GigE/IP. The upgrade process afforded by the hybrid IP/ATM NT 100 should take significantly less time than a drop-in-and-replace overlay type installation and represents a fast and cheap way for current customers to achieve significant video coverage for their subscribers.
It should be noted that the IP/ATM bridge 105, the ATM NT module 110, and the GigE/IP NT module 120 may be implemented in the hybrid IP/ATM NT 100 in many different ways. According to a preferred embodiment they are all part of a single hybrid IP/ATM NT card. In other embodiments the IWF element could be implemented on a GigE/IP NT card which acts as the GigE/IP NT module 120 and a daughter ATM NT card could be situated on the GigE/IP NT card, and would act as the ATM NT module. In other embodiments the IWF element could be implemented on an ATM NT card which acts as the ATM NT module 110 and a daughter GigE/IP NT card could be situated on the ATM NT card, and would act as the GigE/IP NT module. In other embodiments the IWF could be implemented on a daughter card. Many other implementation possibilities exist for the IP/ATM bridge 105, the ATM NT module 110, and the GigE/IP NT module 120 in accordance with the invention.
Although a GigE/IP switch, GigE/IP connection and GigE/IP network interfaces have been described in association with the preferred embodiments of the invention it is to be understood that the GigE/IP NT module operate at any speed and in general is comprised of Ethernet/IP based components such as an Ethemet/IP switch, an Ethernet/IP connection, Ethernet/IP network interfaces, Ethernet/IP bus interface, and an Ethemet/IP star bus.
The embodiments presented are exemplary only and persons skilled in the art would appreciate that variations to the embodiments described above may be made without departing from the spirit of the invention. The scope of the invention is solely defined by the appended claims.
