Communication apparatus, communication method, and computer program product
According to an embodiment, a communication apparatus includes a writing unit, a transfer control unit, a descriptor receiving unit, and a reading unit. The writing unit writes a frame in a first virtual storage area. The transfer control unit controls a timing for transferring a descriptor of the frame based on schedule information. The descriptor receiving unit receives the descriptor. The reading unit that reads the frame from a second virtual storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit.
1. A communication apparatus comprising:
a plurality of network nodes that performs communication; and
a transfer control network node that controls a timing for transferring a descriptor of a frame by a network node of the plurality of network nodes, wherein
each transmission-side network node comprises:
a writing unit that writes, before the timing for transferring the descriptor of the frame, the frame in a first virtual storage area; and
a descriptor transmitting unit that, after the writing unit writes the frame in the first virtual storage area, delivers the descriptor to a transfer control unit;
the transfer control network node comprises:
the transfer control unit that controls the timing for transferring the descriptor of the frame, the transfer control unit comprising:
a first transmission control unit that transfers the descriptor according to first schedule information indicating a frame transmission timing of the transmission-side network node; and
a second transmission control unit that transfers the descriptor according to second schedule information indicating a frame transmission timing of the transfer control network node; and
each reception-side network node comprises:
a descriptor receiving unit that receives the descriptor; and
a reading unit that reads the frame from a second virtual storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit.
2. The apparatus according to claim 1 , wherein
the frame is stored in a first storage area mapped in advance to the first virtual storage area and the second virtual storage area, and
the descriptor includes information that specifies the first storage area in which the frame is stored.
3. The apparatus according to claim 1 , wherein
the first virtual storage area is mapped to a first storage area,
the descriptor includes information that specifies the first storage area mapped to the first virtual storage area in which the frame is stored, and
when the descriptor is received by the descriptor receiving unit, the reading unit maps the second virtual storage area to the first storage area and reads the frame from the second virtual storage area.
4. The apparatus according to claim 1 , wherein
the first virtual storage area is mapped to a first storage area,
the second virtual storage area is mapped to a second storage area,
the apparatus further comprises a copy unit that copies the frame stored in the first storage area to the second storage area when a copy request is received from the writing unit, and
the descriptor includes information that specifies the second storage area to which the frame is copied.
5. The apparatus according to claim 1 , wherein
the first virtual storage area is mapped to a first storage area,
the apparatus further comprises a switching unit that switches a storage area mapped to the first storage area from the first virtual storage area to the second virtual storage area when a mapping switching request is received from the writing unit, and
the descriptor includes information that specifies the second virtual storage area mapped to the first storage area in which the frame is stored.
6. The apparatus according to claim 1 , wherein
the first virtual storage area is managed by a first virtual machine, and
the second virtual storage area is managed by a second virtual machine.
7. The apparatus according to claim 1 , wherein each of the first schedule information and the second schedule information is defined based on IEEE 802.1Qbv.
8. The apparatus according to claim 1 , wherein
the transfer control unit determines the reception-side network node by referring to a forwarding/filtering database (FDB) including information used for determining a transfer destination of the frame;
the transmission-side network node further comprises a virtual FDB that is mapped to a physical memory storing the FDB and that stores therein same information as information of the FDB; and
the writing unit determines, by referring to the virtual FDB, the reception-side network node and writes the frame in an area in the first virtual storage area corresponding to the determined reception-side network node.
9. The apparatus according to claim 1 , wherein
the first transmission control unit controls, by using a system clock in the transfer control network, the timing for transferring the descriptor of the frame based on the first schedule information, and
the second transmission control unit controls, by using the system clock, the timing for transferring the descriptor of the frame based on the second schedule information.
10. A communication method comprising:
by each transmission-side network node of a plurality of network nodes that performs communication,
writing, before a timing for transferring a descriptor of a frame, the frame in a first virtual storage area; and
after writing the frame in the first virtual storage area, delivering the descriptor to a transfer control unit;
by a transfer control network node that controls the timing for transferring the descriptor of the frame by a network node of the plurality of network nodes,
controlling the timing for transferring the descriptor of the frame, the controlling comprising:
first transferring of the descriptor according to first schedule information indicating a frame transmission timing of the transmission-side network node, and
second transferring of the descriptor according to second schedule information indicating a frame transmission timing of the transfer control network node; and
by each reception-side network node of the plurality of network nodes, receiving the descriptor; and
reading the frame from a second virtual storage area specified based on the descriptor when the descriptor is received.
11. A computer program product comprising a non-transitory computer-readable medium including programmed instructions, the instructions causing a computer to function as:
a plurality of network nodes that performs communication; and
a transfer control network node that controls a timing for transferring a descriptor of a frame by a network node of the plurality of network nodes, wherein
each transmission-side network node comprises:
a writing unit that writes, before the timing for transferring the descriptor of the frame, the frame in a first virtual storage area; and
a descriptor transmitting unit that, after the writing unit writes the frame in the first virtual storage area, delivers the descriptor to a transfer control unit;
the transfer control network node comprises:
the transfer control unit that controls the timing for transferring the descriptor of the frame, the transfer control unit comprising:
a first transmission control unit that transfers the descriptor according to first schedule information indicating a frame transmission timing of the transmission-side network node; and
a second transmission control unit that transfers the descriptor according to second schedule information indicating a frame transmission timing of the transfer control network node; and
each reception-side network node comprises:
a descriptor receiving unit that receives the descriptor; and
a reading unit that reads the frame from a second virtual storage area specified based on the descriptor when the descriptor is received by the descriptor receiving unit.