Control signal processor and communication system

A control signal processing apparatus which has a control function for managing establishment and maintenance of a physical signal link and a logical, link and which sends and receives a frame containing a control signal through a physical link and a logical link which have been established, said control signal processing apparatus comprising:

• physical signal link switching-over means for switching over a physical signal link to be used in transmission and reception of control signals to a new physical signal link while holding an already established logical link, in response to a physical signal link switching-over request requiring switch over from one physical signal link to another physical signal link;
• a database for storing a maximum frame length corresponding to each of a plurality of available physical signal links;
• selecting means for selecting a target physical signal link in response to said physical signal link switching-over request;
• and
• a layer 2 processing section for performing processing for said logical link, said layer 2 processing section performing necessary processing for said logical link even though said switching over to said another physical signal link is being performed;
• wherein said layer 2 processing section comprises transmitting means for obtaining the maximum frame length corresponding to said target physical signal link from said database and for transmitting one or more frames having the maximum length and including the control signal.

A control signal processing apparatus which has a control function for managing establishment and maintenance of a physical signal link and a logical link and which sends and receives a frame containing a control signal through a physical link and a logical link which have been established, said control signal processing apparatus comprising:

• physical signal link switching-over means for switching over a physical signal link to be used in transmission and reception of control signals to a new physical signal link while holding an-already established logical link, in response to a physical signal link switching-over request requiring switch over from one physical signal link to another physical signal link;
• and
• a layer 2 processing section for performing processing for said logical link, said layer 2 processing section performing necessary processing for said logical link even though said switching over to said another physical signal link is being performed;
• wherein, when a frame transmitted from an opposite apparatus is lost and the control signal processing apparatus performs a physical signal link switching-over request before receiving a retransmission frame corresponding to the lost frame said physical signal link switching-over means remains in a state in which it is capable of receiving both a frame corresponding to an original physical signal link and a frame corresponding to a target physical signal link until the retransmission frame is received.

A control signal processing apparatus, which has a control function for managing establishment and maintenance of a physical signal link and a logical link and which sends and receives a frame containing a control signal through a physical link and a logical link which have been established, said control signal processing apparatus comprising:

• physical signal link switching-over means for switching over a physical signal link to be used in transmission and reception of control signals to a new physical signal link while holding an already established logical link, in response to a physical signal link switching-over request requiring switch over from one physical signal link to another physical signal link;
• and
• a layer 2 processing section for performing processing for said logical link, said layer 2 processing section performing necessary processing for said logical link even though said switching over to said another physical signal link is being performed;
• wherein the control signal processing apparatus generates said physical signal link switching-over request to switch over a physical signal link for sending and receiving a control signal to a target physical signal link having a less capacity when a call is originated and an information channel has been established.

A control signal processing apparatus which has a control function for managing establishment and maintenance for a physical signal link and a logical link and which sends and receives a frame containing a control signal through a physical link and a logical link which have been established, said control signal processing apparatus comprising:

• physical signal link switching-over means for switching over a physical signal link to be used in transmission and reception of control signals to a new physical signal link while holding an already established logical link, in response to a physical signal link switching-over request requiring switch over from one physical signal link to another physical signal link;
• and
• a layer 2 processing section for performing processing for said logical link, said layer 2 processing section performing necessary processing for said logical link even though said switching over to said another physical signal link is being performed;
• wherein the control signal processing apparatus generates the physical signal link switching-over request to switch over a physical signal link for sending and receiving a control signal to a link corresponding to a new bearer when performing a bearer switching-over operation.

A control signal processing apparatus which has a control function for managing establishment and maintenance of a physical signal link and a logical link and which sends and receives a frame containing a control signal through a physical link and a logical link which have been established, said control signal processing apparatus comprising:

• physical signal link switching-over means for switching over a physical signal link to be used in transmission and reception of control signals to a new physical signal link while holding an already established logical link, in response to a physical signal link switching-over request requiring switch over from one physical signal link to another physical signal link;
• and
• a layer 2 processing section for performing processing for said logical link, said layer 2 processing section performing necessary processing for said logical link even though said switching over to said another physical signal link is being performed;
• wherein when a plurality of calls are in communication and a call using a physical signal link for sending and receiving a control signal has been ended, the control signal processing apparatus generates the physical signal link switching-over request to switch over the physical signal link to another physical signal link corresponding to one of the remaining calls.