1. A method for handling in a packet network a buffer, in which the packets are stored before they are forwarded, in particular in a switch device,', 'each packet belonging to a certain loss priority class and at least two loss priority classes being arranged and', 'each packet also belonging to a certain delay priority class and at least two delay priority classes being arranged, the delay priority classes being intended to give different delays for the packets belonging to said classes, such that longer delays are allowed for packets belonging to delay priority classes having a lower delay priority,', 'for each arrived packet the following steps being performed a) the loss priority class of the packet is determined, b) it is determined if the present total number of packets stored in the buffer is smaller than a threshold value associated with the loss priority class of the packet, c) if the determination in b) gives the answer yes, the packet is stored in the buffer and otherwise it is not stored and is discarded,', 'characterized in', 'that for each incoming packet also the delay priority class of the packet is determined and', 'that in the forwarding of packets from the buffer packets are chosen belonging to a higher delay priority class before packets belonging to a lower delay priority class.

2. A method for handling in a packet network a buffer, in which the packets are stored before they are forwarded, in particular in a switch device,', 'each packet belonging to a certain loss priority class and at

least two loss priority classes being arranged and', 'each packet also belonging to a certain delay priority class and at least two delay priority classes being arranged, the delay priority classes being intended to give different delays for the packets belonging to said classes, such that longer delays are allowed for packets belonging to delay priority classes having a lower delay priority,', 'for each arrived packet the following steps being performed a) the loss priority class of the packet is determined, b) it is determined if the present total number of packets stored in the buffer is smaller than a threshold value associated with the loss priority class of the packet, c) if the determination in b) gives the answer yes, the packet is stored in the buffer and otherwise it is not stored and is discarded,', 'characterized in', 'that for each incoming packet also the delay priority class of the packet is determined and', 'that in the forwarding of packets from the buffer packets are chosen belonging to a higher delay priority class before packets belonging to a lower delay priority class with the further condition that with each lower delay priority class time intervals having predetermined length are associated, such that instead of a packet from a higher delay priority class a packet is chosen from a lower delay priority class, if no packet from the lower delay priority class has been sent during the time interval having the predetermined length associated with the delay priority class thereof and if such a packet is available.

3. A device for handling in a packet network a buffer, in which the packets are stored before they are forwarded, in particular in a switch device,', 'each packet belonging to a certain loss priority class, at least

two loss priority classes being arranged and a threshold value being associated with each loss priority class,', 'each packet also belonging to a certain delay priority class and at least two delay priority classes being arranged, the delay priority classes being intended to allow different delays for the packets belonging to said classes, such that longer delays are allowed for packets belonging to delay priority classes having a lower delay priority,', 'the device comprising', '- an input on which the packets arrive,', '- a memory or a buffer,', '- an output on which the packets are forwarded,', '- a logic unit for determining those packets to be stored in the buffer comprising a) means for determining the loss priority class of an arrived packet, b) means for determining if the present total number of packets stored in the buffer is less than the threshold value associated with the loss priority class of the arrived packet and for forwarding, in the case that this condition is satisfied, a signal thereof to c) means for storing the arrived packet in the buffer,', 'characterized in', 'that the logic unit also comprises', 'd) means for determining for each arrived packet also the delay priority class of the packet and', 'that another logic unit is arranged for determining the packet which is to be sent from the buffer comprising', 'means for choosing packets belonging to a higher delay priority class before packets belonging to a lower delay priority class and for transferring the selected packet to the output for forwarding.

4. A device for handling in a packet network a buffer, in which the packets are stored before they are forwarded, in particular in a switch device,', 'each packet belonging to a certain loss priority class, at least two loss priority classes being arranged and a threshold value being associated with each loss priority class,', 'each packet also belonging to a certain delay priority class and at least two delay priority classes being arranged, the delay priority classes being intended to allow different delays for the packets belonging to said classes, such that longer delays are allowed for packets belonging to delay priority classes having a lower delay priority,', 'the device comprising', '- an input on which the packets arrive,', '- a memory or a buffer,', '- an output on which the packets are forwarded,', '- a logic unit for determining those packets to be stored in the buffer comprising a) means for determining the loss priority class of an arrived packet, b) means for determining if the present total number of packets stored in the buffer is less than the threshold value associated with the loss priority class of the arrived packet and for forwarding, in the case that this condition is satisfied, a signal thereof to c) means for storing the arrived packet in the buffer,', 'characterized in', 'that the logic unit also comprises', 'd) means for determining for each arrived packet also the delay priority class of the packet and', 'that another logic unit is arranged for determining the packet which is to be sent from the buffer comprising

means for choosing packets belonging to a higher delay priority class before packets belonging to a lower delay priority class with the further condition that each lower delay priority class is associated with time intervals having predetermined lengths, such that instead of a packet from a higher delay priority class a packet is chosen from a lower delay priority class if no packet from the low delay priority class has been forwarded during the time interval with the predetermined length associated with the delay priority class thereof and if such a packet is available, and', 'means for transferring a chosen packet to the output for forwarding.

5. A method for handling in a packet network a buffer, in which the data packets are stored before they are forwarded, each packet belonging to a certain one of at least two delay priority classes, characterized in that in the forwarding of packets from the buffer packets are chosen belonging to a higher delay priority class before packets belonging to a lower priority class with the further condition that each lower delay priority class is associated with time intervals having predetermined lengths, such that instead of a packet from a higher delay priority class a packet is chosen from a lower delay priority class, if no packet from the lower delay priority class has been sent during the time interval having the predetermined length associated with the delay priority class thereof and if such a packet is available.

6. A device for handling in a packet network a buffer, in which the packets are stored before they are forwarded, each packet belonging to a certain one of at least two delay priority classes, comprising', '- an output on which the packets arrive,', '- a memory or a buffer,', '- an output on which the packets are forwarded from the buffer,', 'characterized by

a logic unit for the determination of the packet, which is in turn to be forwarded from the buffer, comprising', 'means for choosing packets belonging to a higher delay priority class before packets belonging to a lower delay priority class with the further condition that each low delay priority class is associated with time intervals having predetermined lengths, such that instead of a packet from a higher delay priority class a packet is chosen from a lower delay priority class, if no packet from the low delay priority class has been sent during the time interval having the predetermined length associated with the delay priority class thereof and if such a packet is available, and', 'means for transferring the chosen data packet to the output for forwarding.1. A device according to claim 6, characterized by memory means associated with each delay priority class for storing addresses to the data packets which belong to this delay priority class and which are stored in the buffer.', '8. A device for handling in a packet network a buffer, in which the packets are stored before they are forwarded, each packet belonging to a certain one of at least two delay priority classes, comprising', '- an output on which the packets arrive,', '- a memory or a buffer,', '- an output on which the packets are forwarded from the buffer,', 'characterized by', 'a logic unit for the determination of the packet, which is in turn to be forwarded from the buffer, comprising', 'means for selecting packets belonging to a higher delay priority class before packets belonging to a lower delay priority class by means of lists stored in memory means for each delay priority class, these lists each one accommodating addresses to the data

packets, which belong to this delay priority class and which are stored in the buffer, and', 'means for transferring a chosen data packet to the output for forwarding.', '9. A device according to one of claims 7 - 8, characterized by queue arranging means, which are arranged to store, for arrived data packets, which are stored in the buffer, the addresses to these data packets in corresponding memory means associated with the delay priority class, to which each data packet belongs, and for further placing the addresses to stored data packets belonging to a delay priority class in a definite order in the memory means associated with this delay priority class.10. A device according to claim 9, characterized in that the queue arranging means are provided, in the placing of addresses, to use a sequential order, which corresponds to the time order, in which the data packets having these addresses have arrived.']