JP2002527944A - Method and apparatus for establishing a communication channel in a DTM network - Google Patents

Abstract

SUMMARY The present invention relates to a method and apparatus for establishing a communication channel in a DTM network. In accordance with the present invention, a DTM channel is established from a first node (N4) to a second node (N9) via one or more intermediate nodes (N5, N6, N8). Further, a set of one or more DTM channels within the DTM channel is established, typically using control signaling between the first and second nodes, and one or more intermediate Nodes do not participate in the transmission of their control signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION

The present invention relates to a method and an apparatus for establishing a communication channel in a DTM network.

[0002]

[Background Art]

In recent years, the need for network solutions that provide quality of service in high-bandwidth applications has gradually evolved as a result of the increasing demand to transfer real-time voice, video, and multimedia over networks such as the Internet.

[0003] It has been discovered that the use of circuit-switched networks, which have the unique property of providing each host with guaranteed bandwidth, may provide advantageous features in this regard.

A new circuit-switched network solution that has attracted much interest in the last few years is known as DTM (Dynamic Synchronous Transfer Mode). In this DTM network, circuit-switched channels are dynamically established, modified, and terminated based on changes in user capacity requirements.

[0005] However, a disadvantage of circuit-switched network solutions such as DTM is that dynamic management of the channel requires signaling overhead. As the number of dynamically managed channels increases, the number of nodes involved in managing the channels increases, and the signaling overhead increases so that the use of the dynamic aspects of DTM technology is severely impeded. Become.

In view of the above, it is an object of the present invention to provide a solution for reducing the control signaling requirements in a circuit switched network of the kind described above, in particular a DTM network.

[0007]

Summary of the Invention

The above and other objects are achieved by the invention as defined by the appended claims.

[0008] According to a first aspect of the present invention, there is provided a method for establishing a communication channel in a DTM network, the method comprising: connecting one or more intermediate nodes from a first node to a second node. Establishing a DTM channel over the same and a set of one or more DTs within the one DTM channel
Establishing an M channel.

According to a second aspect of the present invention, there is provided an arrangement for establishing a communication channel in a DTM network, the apparatus comprising a first node, a second
A node, means for establishing a DTM channel from the first node to the second node via one or more intermediate nodes, and a set of one or more DTM channels within one DTM channel Means for establishing

The present invention is therefore based on the idea of dealing with a plurality of DTM channels, sometimes called DTM subchannels, as components of one DTM channel, sometimes called DTM main channel or DTM “tunnel” I have. The present invention therefore provides for the distribution of time slots among DTM sub-channels, the size of DTM main channels, or the assignment of time slots to DTM main channels without necessarily affecting the management of DTM main channels. Manage, change, modify, etc.

Advantageously, when the DTM main channel and thus the DTM sub-channel extends from one transmitting node to one receiving node via one or more intermediate nodes, the intermediate node is simply a time slot to the DTM main channel. Only need to be involved in the allocation and management of the DTM sub-channel, whereas the definition of the DTM sub-channel is without intermediate nodes involved in control signaling.
It is managed between terminals (end to end). Thus, the DTM sub-channel resolution need only be provided at the transmitting and receiving nodes and / or at the end of the DTM main channel, and does not require intermediate nodes.

The elimination of having to involve intermediate nodes in the management of multiple DTM subchannels, all of which extend over the same network path, greatly reduces signaling requirements, especially when the number of intermediate nodes is large. Provides a very advantageous advantage.

According to an embodiment of the present invention, the DTM sub-channel includes one or more control channels. In a conventional DTM network, a node typically has access to a control slot through which the node sends control messages to other nodes located on the same link (such as a bus or ring). You can do it. However, control signaling to nodes on other links is possible without the involvement of an intermediate node that has access to the control channel on the other link and thus can handle the required control signaling on that link. Is impossible. Therefore, when managing channels that reach across multiple links, not just one link, multiple intermediate nodes are typically hop by hop basi
s) must be responsible for exchanging control messages.

According to the present invention, by setting up a DTM main channel arriving over multiple links, and by defining a DTM control channel within the DTM main channel, the DTM control channel is located on other links. Provide a direct signal transmission path to the active node. To that end, the DTM main channel can be viewed as a virtual link that connects all nodes using the main channel and sends and / or receives control messages or payload data. However, any intermediate node that simply maps the DTM main channel without involving the actual transmission / reception of data in the channel or its DTM subchannel, manages the channels within that main channel, ie, on the virtual link. Not involved in channel management in

As will be apparent, the present invention significantly reduces the amount of signaling required within a DTM network.

According to another embodiment of the present invention, the channels received from one or more input bitstreams are mapped at the “input end” of the DTM main channel to respective DTM subchannels of the DTM main channel. Is done. Each DTM subchannel of the DTM main channel is then mapped to a respective output channel of one or more output bitstreams at the "output" of the DTM main channel. The present invention therefore provides a means for multiplexing channels over a larger portion of the network into larger channels.

Furthermore, the division of DTM channels into DTM subchannels according to the invention is used cyclically. In other words, according to another embodiment, a plurality of DTM sub-channels are transferred within a DTM main channel, which DTM main channel is in turn transferred together with other DTM channels as part of a higher DTM main channel, The same applies hereinafter. Creating a "virtual link" in the form of a DTM main channel according to the invention therefore takes place over several hierarchical link levels.

According to another embodiment of the present invention, data transferred within the DTM main channel is encrypted as a whole, not for each sub-channel. As a result, it becomes more difficult for a fraudulent user to decipher the DTM subchannel, increasing network security and its integrity.

According to a third aspect of the present invention, there is provided a method for handling a communication channel in a DTM network, the method comprising:
Accessing a first link of the M network, from the first interface to one or more prospective receivers where at least one is located on another link of the DTM network and arrives via at least one switching node of the network Establishing one DTM channel, a virtual link whose connectivity is defined by the intended receiver of the DTM channel, and a set of associated virtual links and defining one DTM channel on the first link. Defining a virtual interface defined by access to the timeslot, and establishing one or more DTM channels on a virtual link to one or more of the prospective receivers.

A third aspect of the invention therefore provides an advantageous method for a node of a network that handles the division of a DTM main channel into DTM subchannels according to the first and second aspects of the invention.

By considering one DTM main channel of the type described above as a separate virtual interface and operating the nodes accordingly, the use of the present invention is occupied for complex separate software processing and / or management. It is easily implemented without having to design the memory function as well as the resolution of the DTM subchannel. Since the virtual interface according to the present invention is used cyclically, the depth of the sub-channel partitioning handled in a preferred manner using one and the same software function, as further explained with reference to FIG. 4 below (That is, the division of the DTM subchannel into DTM subchannels) can be increased.

According to an embodiment of the latter aspect of the invention, one or more DTM subchannels are divided into DTM control channels and DTM data channels, where the DTM data channels on the virtual link are managed. Signaling is performed using one or more DTM control channels. This provides a mechanism for transmitting control messages between nodes located on separate links transparent to intermediate nodes, as discussed above.

As will be appreciated, the term “intended receiver” is configured to transmit or receive data (control signaling or payload data) using the DTM main channel or its DTM subchannel. Indicates the unit (node) that has been set. In other words, the DTM main channel (and hence the DT in the main channel) from one bit stream to another bit stream that is not actually configured to receive or transmit data in the main channel
Nodes that do not participate in sub-channel resolution simply by mapping M sub-channels) are not considered "scheduled receivers."

The use of the unicast DTM main channel, that is, the use of a “tunnel” from point to point, where a single node acts as an entry point and a single other node acts as an exit point, is a feature of the invention. This is the most common use. In such a case, the virtual link formed by the DTM main channel is a unicast link. However, in another embodiment, a multi-access DTM main channel, ie, a DTM main channel accessed and used by multiple nodes, is equally advantageous. In the latter case, the virtual link formed by the multi-access DTM main channel is therefore considered a multi-access link. To that end, in the latter case, the node with access to the multi-access DTM tunnel may access the multi-access DTM tunnel, read data from one or more of the DTM subchannels and / or send data to them. For example, add-drop associated with the DTM sub-channel of the DTM main channel.
(add-drop) Works like a multiplexer. In such a case, D
The virtual links formed by the TM main channel are arranged and appear to form, for example, a virtual single ring or bus link topology on the actual DTM topology.

By definition, a “DTM network” as referred to herein is a type of circuit-switched time division multiplexed network in which information is transferred between nodes of the network on a bitstream. Each bitstream is divided into frames, usually circular and essentially fixed-size called "DTM frames", each frame containing a fixed number of time slots, the time slots being control and data slots. And separated. Thus, at some point at each point in time, D
The time slot position of the TM frame defines a control slot or a data slot. Control slots are used for control signaling between nodes of the network, and data slots are used for transfer of user data (often called payload data). However, it should be noted that control slots and data slots are basically handled in the same way on the link level. The only difference between these two is that they are used in two different ways by the nodes of the network.

Further, in a DTM network, write access to the time slots of a DTM frame is distributed among the nodes attached to the bitstream carrying the DTM frame, where each node typically has at least one It has write access to one control slot and a set of dynamically adjustable data slots within each cyclic frame. Further, having write access to a time slot location within a frame means having write access to that time slot location within each cyclic frame.

In a DTM network, nodes use data slots with write access to establish a so-called “DTM channel” by allocating one or more data slots to each DTM channel. Therefore, the DTM channel described here ("main channel" or "sub-channel")
Is defined by one or more time slots that occupy the same time slot position in each DTM cyclic frame of the bitstream in which the DTM channel is carried. However, if the DTM channel arrives, for example, over two bit streams, the channel is, of course, defined by different sets of time slot positions on the two bit streams. A DTM channel is a control channel or a data channel depending on whether it is a control slot or a data slot assigned to the channel. Furthermore, DTM channels are unicast (point-to-point), multicast (point-to-point).
Point-to-multipoint) or broadcast.

As network capacity requirements change, DTM channels are dynamically established, terminated, or modified by changing the number of time slots assigned to the DTM channels. Also, the distribution of write access to time slots among different nodes is dynamically modified as different nodes evolve into different needs for control signaling and data transfer.

For further description of DTM networks, see, eg, “DTM Gigabit Networks”, Christer Baume et al., High Speed Network Journal, Vol.
. 3, Nr. 2, 1994, pp 109-126.

[0030] In addition to the advantageous feature of reducing control signaling in the network, an advantageous and preferred embodiment of the present invention provides for a network operator to a customer connected to that network or, for example, on a first operator's network. When it is desired to allocate a certain capacity to other network operators seeking to offer network services at the same time, and to have that customer / operator control the DTM channel to be established only within the capacity thus allocated. It is time to want. This task can be solved with the present invention by establishing a main channel to be used by the client / operator, authorizing the client / operator and setting the DTM only within its DTM main channel.
Allow access to form subchannels.

The above and other aspects and features of the present invention, such as the use of switched core memory shared by all switched ports and the use of router memory shared by all channels accessed by router means, are described below. Will be fully understood from the description of the embodiments.

[0032]

【Example】

A circuit switched time division multiplexing network operating according to the DTM (Dynamic Synchronous Transfer Mode) protocol will be described with reference to FIG. In FIG. 1, the DTM network NW includes a plurality of nodes N1-N11 connected via four unidirectional bit streams B1-B4. Typically, each of this bit stream B1-B4 is used together with a respective bit stream (not shown) propagating in the opposite direction, thereby connecting all nodes associated with the bit stream. Form a link. Nodes N1-N4 are attached to bit stream B1, nodes N4-N7 are attached to bit stream B2, and nodes N6, N8 and N9.
Is attached to bit stream B3, and nodes N9-N11 are attached to bit stream B4.

The nodes in FIG. 1 typically provide end users (not shown) with access to the network. However, the network also includes nodes that do not provide network access to end users. For example, the node
It merely provides for the exchange of data between the different links of the network, such as switching nodes N4, N6 and N9. In addition, one or more of the nodes interconnect the DTM network TW to an external network (not shown) such as the network of the DTM network shown in FIG. 1, for example, a network of Ethernet. I do.

As an example, the bit stream B 1 in FIG.
The data transfer structure used on -B4 will be described with reference to FIG.

As shown in FIG. 2 (a), the bit stream B 2 is cyclic and essentially divided into fixed-size frames, where the start of each frame is defined by a frame synchronization time slot F. You. As an example, each frame is 125
It has a reference time period of microseconds.

As shown in FIGS. 2 (b) and 2 (c), each frame is divided into a number of time slots, typically of a fixed size of 64 bits. If the above 125
Microsecond frame length, 64-bit time slot size and 2 Gbps
, The total number of time slots in each frame is approximately 3900.

A time slot is generally divided into control slots C4-C7 and data slots D4-D7. Control slots are used for signaling between nodes of the network, while data slots are used for transfer of payload data. At the start of the network, each node connected to the bitstream B2 is typically assigned to at least one control slot. Further, the data slots are divided among the nodes connected to the bitstream. Thus, as shown in FIG. 2 (b), at the start of the network, node N4 accesses control slot C4 and a set of data slots D4 in each frame of the bit stream, and node N5 receives control slot C5 and control slot C5. Access a set of data slots D5 in each frame of the bitstream, and so on. The set of slots assigned to a node as control slots and / or data slots occupy the same slot position within each frame of the bitstream. Therefore, in the embodiment, the control slot C4 belonging to the node N4 occupies the second time slot in each frame of the bit stream.

During operation of the network, each node increases or decreases its access to slots, so that access to data and / or control slots is redistributed among nodes. For example, a node with a low transfer capacity requirement gives access to a timeslot to a node with a high transfer capacity requirement. Further, the slots assigned to the nodes need not be contiguous slots and may be anywhere in the frame.

Each frame starts with a frame synchronization time slot that defines a frame rate on the bitstream and ends with one or more guard band time slots G.

For example, node N4, which has accessed at least one control slot and a plurality of data slots, uses the control slot C4 to send control messages related to the management of the DTM channel, and uses a subset of the plurality of data slots in the DTM channel. To establish a DTM channel on the bit stream B2.

FIG. 2 (c) shows the prior art situation, where node N 4 accessing control slot C 4 and data slot D 4 on bit stream B 2 has established four channels CH 1, CH 2, CH 3 and CH 4. I have.

In this example, channel CH4 is a DTM channel from node N4 to node N7, which allocates seven data slots within each frame on bit stream B2 and uses control slot C4 to Inform the receiving node N7 about the existence of the channel CH4.

Also, by allocating a time slot within each frame on bit stream B2 and by requesting switching node N6 to allocate a corresponding set of time slots on bit stream B3, node N4 Set up DTM channel CH1 including four slots in each frame on B2 at node N9.

Further, upon receiving channel establishment requests from nodes N1 and N2 on bit stream B1, node N4 places DTM channel CH on bit stream B2.
2 and CH3 are established. Channel CH2 forms part of a multi-hop channel from node N1 to node N11, and channel CH3 is
2 form part of the multi-hop channel to node N10. As will be appreciated, the time slots of channels CH1, CH2 and CH3 are allocated correspondingly on bit streams B2, B3 and B4.

In FIG. 2C, as an example, since the number of time slots allocated to channel CH4 is larger than the number of time slots allocated to channel CH1, the transfer capacity of channel CH4 is larger than the transfer capacity of channel CH1. . DT
The time slots assigned to the M channels occupy the same time slot position within each cyclic frame of the bitstream.

FIG. 2 (d) shows that the node N 4 that has recognized many channels established to / through the node N 7 adds the node CH from the node N 4 to the node N 7 in addition to the channel CH 4 to the node N 7 described above. Indicates that the DTM main channel CH10 has been established via N6. Thus, all traffic of the time slot in channel CH10 on bit stream B2 is mapped by node N6 to the corresponding channel portion on bit stream B3 so as to reach node N9.

In the DTM main channel CH 10, three DTM sub-channels CH 11 and CH 3 corresponding to the above-described channels CH 1, CH 2 and CH 3 in FIG.
CH12 and CH13 are defined. Similar to the channel in FIG.
Each DTM subchannel is defined to include a respective set of slots in each bitstream frame. In addition, node N4 uses the control slot to send a control message to node N9, and sends one time slot in its channel (the first time slot of the channel in each frame) to control slot C4v. Thus, node N4 has access to one control slot C4 received by all nodes on link L3, and has access to main channel CH20.
Access one control slot C4, which is transferred within and received by node N9.

As a result, when managing the assignment of time slots to channels in the main channel CH10, the node N4 uses the node N6 as an intermediate negotiator to reach the node N9 and no longer transmits control messages via the control slot C4. No need to replace. Alternatively, node N4 can send control messages directly to node N9 by using control slot C4v defined in its main channel CH10. Therefore, the main channel CH10 is regarded as a virtual link providing a virtual direct connection between the nodes N4 and N9. Similarly, the main channel CH10 on the bit stream B2 at the node N4
Are considered to form a virtual interface accessing the virtual link.

As an example, FIG. 2 (e) shows a situation where the definition of the DTM sub-channel within the DTM main channel is changed due to changes in capacity requirements. In FIG. 2E, the channel CH11 ends, the channel CH12 is not changed, and the bandwidth of the channel CH13 is increased. However, the main channel CH10
The size and assignment of time slots to is unchanged. To that end, all necessary control signaling between nodes N4 and N9 is controlled by control slot C4v
, And all changes related to the assignment of time slots to channels on bit streams B2 and B3
Since they are made inside H10, these changes do not require, for example, the recognition or interaction of node N6.

For example, if the invention is used as a means for a network operator to hand over control of a portion of the network capacity to a customer, such as an end user or other network operator who wants to offer services on the network. , DTM subchannels such as channels CH11, CH12 and CH13 in the DTM main channel CH10 are handed over to the customer.

The design of the nodes of the network in FIG. 1 will be described with reference to FIG. 3, taking the node N 4 as an example.

In this example, the node 10 of FIG. 3 is assumed to be the node N 4 of FIG.
0 includes four 2-port physical in / out interfaces 10, 20, 30 and 40, with first and third interfaces 10 and 30 providing read / write access to bit streams B1 and B2, respectively. Second and fourth interfaces 20 and 40 provide read / write access to respective unidirectional bit streams (not shown in FIG. 1) that are propagated in opposite directions relative to bit streams B1 and B2. I do.

The interfaces are all connected to a shared memory 50, which shares the time and space of data between the links connected to the nodes.
ace) is used for each slot. Shared memory 50 includes a frame buffer for each received bit stream. Thus, for example, bitstream frames received by interface 10 are sequentially written into shared memory 50 for temporary storage therein. At the same time, bitstream frames received by interface 20 are sequentially written to other portions of shared memory 50 for temporary storage therein, and so on.

Further, each of the physical interfaces 10, 20, 30, and 40 includes a slot mapping table 11 used when transmitting data to each bit stream.
, 21, 31, and 41. Each slot mapping table has one entry for each outgoing time slot of the outgoing bit stream frame to be transmitted, and each entry has a shared memory 5 for each outgoing time slot.
Provides a pointer that indicates where to read data from zero.

The contents of the slot mapping table are indirectly controlled by the node controller 60. The node controller 60 is arranged to read data from one or more locations in the shared memory, which location is located in a control slot of another node's control channel to receive control messages from other nodes. Yes, it is. Similarly, the node controller 60 is arranged to write data to one or more locations of the shared memory 50, the location of which is transmitted to other nodes in order to send control messages to other nodes. It corresponds to the control slot of the control channel of the node itself.

For example, when establishing a new channel based on a channel establishment request received from another node and thus read from a location in shared memory 50, the node controller may determine which receivers reach each interface. Access a routing table 70 that provides information about the However, this interface is an actual interface (that is, interface 11, 21,...) Or a virtual interface (described above). Based on such information, the node controller provides an input to the channel table 80 and sends a channel announcement message to the other nodes (at the location corresponding to the output control channel of the shared memory 50, the channel announcement message). Set up the channel).

Channel table 80 provides one input list for each channel handled by node 4. Information is provided for each channel entry in the channel table 80, from which interface (real or virtual) data is received for each channel, and the location of its corresponding time slot, or that channel. Indicate which interface (real or virtual) to use when transmitting data within and its corresponding timeslot location.

The channel table is connected to an interface mapping unit 90 that provides a mapping between virtual channels / slots and actual channels / slots. For example, the interface mapping unit may determine that slots 2-20 of (virtual) interface 1 (virtual interfaces are not shown in FIG. 3 of course because they are virtual) but slots 12-30 of (real) interface 10 Is included in the table (not shown) that describes the correspondence to.

In a cyclic manner, ie when the main channel comprises a number of sub-channels, at least one of which sub-channels also comprises a number of sub-sub-channels, and so on using the virtual interface in a similar manner, the interface mapping unit The interface mapping table used by 90 contains the cyclic mapping instructions. For example, when the slot 2-4 of the (virtual) interface 2 is (
One input indicating that it corresponds to slot 6-8 of (virtual) interface 1 and slot 6-8 of (virtual) interface 1
It has another input to indicate that it corresponds to zero slots 100-102.

If the establishment of a channel involves the establishment of a virtual interface / link, as mentioned above, the node controller ensures that the channel table 80 and the interface mapping unit 90 are updated accordingly.

When using the interface mapping table, the interface mapping unit 90 translates the channel list of the channel table 80 and confirms that the necessary pointers of the slot mapping tables 11, 21, 31 and 41 are provided. . Therefore, the slot mapping table is constantly updated according to the correct mapping instruction.

FIG. 4 schematically shows a simplified diagram of the DTM network of FIG. This figure 4
In the same manner as described above, it is assumed that the node N4 establishes the main channel CH30 to the node N9 via the node N6, and that the main channel is a time slot in each frame of the bit stream B2. 1,2,4,5
, 6, 9, 10, 11 and 12 and time slots 5, 6, 7, 8, 9, 10, 12, 13 and 14 in each frame of the bit stream B3. In addition, using the control signaling between nodes N4 and N9, the first two of this set of slots, including nine slots in each frame on the two bit streams,
One slot is allocated to subchannel CH31, the next two slots are allocated to subchannel CH32, and the last four slots are allocated to subchannel CH33, and the fifth slot remaining in the set of slots is still allocated. Define that there is no.

Tables 1 and 2 show examples of the contents of the channel table and the interface mapping table provided in the node N4 in the situation described with reference to FIG.

[0064]

[Table 1]

[0065]

[Table 2] As can be seen from Table 1, node N4 determines whether interface 30 (the actual interface (out) to bitstream B2) forms interface 3 (in this case, a virtual interface) offering slot 1-9 on that interface. )), A channel is formed by slots 1, 2, 4, 5, 6, 9, 10, 11 and 12.

Further, the channel CH 31 is connected to the slots 1 and 2 of the (virtual) interface 3.
Which is translated into slots 1 and 2 of the actual interface 30 using Table 1. Similarly, channel CH32 is defined to include slots 3 and 4 of (virtual) interface 3, which is translated to slots 4 and 5 of actual interface 30 using Table 1.

Tables 3 and 4 show examples of the contents of the channel table and the interface mapping table provided in the node N6 in the same situation as described above.

[0068]

[Table 3]

[0069]

[Table 4] As can be seen from Table 3, node N6 does not define any virtual interfaces at this time. Further, as can be seen in Table 4, channel CH30 is the slot 1, 2, 4, 5, 6, 9, 10, 11 and 12 of ingress interface 10 (the actual physical interface to bit stream B2) of node N6 and its It is defined to include slots 5, 6, 7, 8, 9, 10, 12, 13, and 14 of the outgoing interface 40 (the actual physical interface to bit stream B3).
Therefore, as is apparent from Tables 1 and 2, at this point, the node N6
Does not know the existence of a subchannel in channel CH30.

Although the invention has been described with reference to illustrative embodiments of the invention, these embodiments should not be considered as limiting the scope of the invention. Thus, as will be appreciated by those skilled in the art, different proprietaryities, combinations and variations may be made within the scope of the invention as defined by the appended claims.

[Brief description of the drawings]

FIG. 1 schematically illustrates a DTM network operating in accordance with one embodiment of the present invention.

FIG. 2 schematically shows the assignment of time slots to DTM channels on a bit stream, FIGS. 2 (a) -2 (c) show prior art, and FIG.
FIG. 2 (e) shows one according to an embodiment of the present invention.

FIG. 3 is a block diagram schematically illustrating a node of the network of FIG. 1;

FIG. 4 schematically shows a simplified diagram of the DTM network of FIG.

[Explanation of symbols]

 TW DTM network B1-B4 Bit stream N1-N11,100 Node 10, 20, 30, 40 Interface 50 Shared memory 60 Node controller 70 Routing table 80 Channel table 90 Interface mapping unit

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Claims (35)

[Claims] 1. A method for establishing a communication channel in a DTM network, comprising establishing one DTM channel (CH10) from a first node to a second node via one or more intermediate nodes. , And a set of one or more DTM channels (CH11, C
H12, CH13). 2. The method according to claim 1, wherein said set of DTM channels is established within said one DTM channel using control signaling between said first node and said second node, and wherein said one or more intermediate nodes are The method of claim 1, wherein said is not involved in said control signaling. 3. The method according to claim 1, wherein the control signaling is performed in the one DTM channel. 4. The method according to claim 1, wherein the management of the set of DTM channels is performed using one or more DTM channels (C4v) forming the set of DTM channels. . 5. The method according to claim 1, wherein said one DTM channel is a unicast channel, and said first and second nodes form their endpoints. 6. The method according to claim 1, wherein said one DTM channel is a multicast channel and extends beyond at least one of said first node and said second node. 7. The method according to claim 1, wherein said one DTM channel extends over a plurality of intermediate nodes. 8. The method of claim 1, wherein one or more DTM channels of the set of DTM channels extend beyond an end of the one DTM channel. 9. Each of said one or more intermediate nodes exchanging said one DTM channel between two bitstreams of said DTM network comprises:
Arranged to provide slot mapping to slots between a set of time slots defining the one DTM channel on one bitstream.
A method according to any of the preceding claims. 10. Each of the one or more intermediate nodes that exchanges the one DTM channel from one bitstream of the DTM network to another bitstream, The method according to any of the preceding claims, wherein the method participates in establishing the one DTM channel by assigning a respective set of time slots to one DTM channel. 11. Transferring multiple isochronous channels from one or more first bitstreams to one or more second bitstreams over said one DTM channel; The method according to any of the preceding claims, wherein each one of the temporal channels is mapped to a respective DTM channel of the set of DTM channels. 12. The method according to claim 1, further comprising the step of encrypting information transferred in said one DTM channel as a whole. 13. The method according to claim 1, comprising dynamically changing the size of said one DTM channel. 14. The method according to claim 1, wherein the size of the one DTM channel is changed as a result of a change in the total capacity requirement of the set of DTM channels. 15. The system of claim 1, wherein a first network operator controls the establishment of the one DTM channel on the DTM network, and a second network operator controls the establishment of the set of DTM channels. The method according to any of the above. 16. An apparatus for establishing a communication channel in a DTM network, comprising: a first node (N4; 100), a second node (N9; 100), one from the first node to the second node. Or means (60,80) for establishing one DTM channel via one or more intermediate nodes, and means for establishing a set of one or more DTM channels within said one DTM channel An apparatus comprising (60,80,90). 17. The DTM channel of claim 1, wherein the set of DTM channels is established within the one DTM channel using control signaling between the first node and the second node, wherein the control signaling is the one or the other. 17. The apparatus of claim 16, wherein the apparatus does not include any further intermediate nodes. 18. The method according to claim 1, wherein the control signaling is performed within the one DTM channel.
An apparatus according to claim 7. 19. The management of the set of DTM channels is performed using one or more DTM channels forming the set of DTM channels.
An apparatus according to claim 8. 20. Apparatus according to claim 16, 17, 18 or 19, wherein said one DTM channel is a unicast channel and said first and second nodes form an end point thereof. 21. The one DTM channel is a multicast channel and extends beyond at least one of the first node and the second node.
20. Apparatus according to 8 or 19. 22. The single DTM channel extends across a plurality of intermediate nodes (N5, N6, N8).
Apparatus according to any of claims 16 to 21. 23. The apparatus of claim 16, wherein one or more DTM channels of the set of DTM channels extend beyond an end of the one DTM channel. 24. Each of said one or more intermediate nodes (N6) for exchanging said one DTM channel between two bitstreams of said DTM network comprises: 24. The apparatus according to any of claims 16 to 23, wherein the apparatus is arranged to provide slot mapping for slots between a set of time slots defining the one DTM channel. 25. Each of said one or more intermediate nodes (N6) for exchanging said one DTM channel from one bit stream of said DTM network to another bit stream comprises said other bit stream. By assigning each set of time slots to the one DTM channel above,
An apparatus according to any of claims 16 to 24, arranged to participate in the step of establishing a TM channel. 26. The means for establishing a set of DTM channels includes: converting one or more isochronous channels received at the first node to respective DTM channels of the set of DTM channels. Apparatus according to any of claims 16 to 25, arranged for mapping. 27. The means for establishing a set of DTM channels may map one or more of the set of DTM channels to respective isochronous channels transmitted from the second node. Apparatus according to any one of claims 16 to 26, wherein the apparatus is arranged at: 28. The apparatus according to claim 16, wherein the means for establishing one DTM channel is arranged to dynamically change the size of the one DTM channel. 29. The means for establishing one DTM channel is arranged to change a size of the one DTM channel as a result of a change in a total capacity requirement of the set of DTM channels. Item 30. The apparatus according to any one of Items 16 to 28. 30. A method for handling a communication channel in a DTM network, the method comprising: accessing a first link of the DTM network via a first interface, wherein at least one of the first interface comprises: Establishing one DTM channel to one or more prospective receivers located on another link and arriving via at least one switching node of the network, by the prospective receiver of the one DTM channel A virtual link for which connectivity is defined and the one DTM associated with the virtual link and on the first link
Defining a virtual interface defined by access to a set of time slots defining a channel; and a set of ones to one or more of the prospective receivers on the virtual link.
A method comprising establishing one or more DTM channels. 31. The method according to claim 30, comprising dividing the data slots forming the DTM channel into control slots and data slots. 32. The one or more DTM channels may be a DT used to manage the one or more DTM channels within the one DTM channel.
The method according to claim 30 or 31, comprising an M control channel. 33. accessing a second link of the DTM network via a second interface; receiving one or more DTM channels on the second link; and establishing on the virtual link 33. The method of claim 30, 31 or 32, comprising mapping one or more DTM channels received on the second link to respective DTM channels. 34. A method according to claim 1, wherein one set of one or more time slots occupies the same time slot position within each cyclic frame of the time division multiplexed bit stream.
34. The method according to any of claims 30 to 33, wherein a TM channel is defined. 35. The method of claim 30, wherein a first network operator controls the establishment of the one DTM channel on the DTM network, and a second network operator controls the establishment of the set of DTM channels. The method according to any of the above.