Patent EP0871309A2 successfully refreshed from Google Patents.
EP0871309A2
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EP
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Router device and frame transfer method using datalink layer frame switching
Assignee: Toshiba Corp
•
Filing: 1998-04-07
•
Granted: —
•
Expires: 2018-04-07
Abstract
Abstract A router device and a frame transfer method capable of attaching a virtual identifier necessary for the datalink layer switching that improves a transfer efficiency at the router device. The router device receives a frame having a datalink flow identifier for identifying a flow of a packet corresponding to the frame on a datalink layer, which is contained in a prescribed region of the frame corresponding to an upper layer protocol identification information region of a frame format for frames to be transferred via a network layer processing, and transfers the frame received from a previous hop node to the next hop node by obtaining the address information of the next hop node by referring to the memory unit using at least the datalink flow identifier contained in a prescribed region of the frame as a key, and by attaching the address information of the next hop node to the frame, without carrying out the network layer processing, where the memory unit stores a correspondence of the datalink flow identifier and an address information of the next hop node.
Inventors
- 👤 Shigeo Matsuzawa
- 👤 Yasuhiro Katsube
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 09:20
CPC Classifications
H; H04; H04L; H04L49/00; H04L49/60; H04L49/602; H04L12/00; H04L12/28; H04L12/46; H04L12/4604; H04L49/25; H04L49/251; H04L49/35; H04L49/351
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
208 words
A router device, comprising: a receiving unit for receiving a frame to be
transferred by a datalink layer level switching, said frame
having a datalink flow identifier for identifying a flow of
a packet corresponding to said frame on a datalink layer,
the datalink flow identifier being contained in a
prescribed region of said frame corresponding to an upper
layer protocol identification information region of a frame
format for frames to be transferred via a network layer
processing; a memory unit for storing a correspondence of the
datalink flow identifier and an address information of a
next hop node to which frames of packets belonging to said
flow are to be transferred next; and a datalink layer level transfer unit for transferring
said frame received from a previous hop node belonging to
one logical network by the receiving unit to the next hop
node belonging to another logical network, by obtaining the
address information of the next hop node by referring to
the correspondence stored by the memory unit using at least
the datalink flow identifier contained in said prescribed
region of said frame as a key, and by attaching the address
information of the next hop node to said frame, without
carrying out the network layer processing.
Claim 2
Dependent Claim
66 words
The router device of claim 1, wherein the receiving
unit also receives another frame to be transferred via the
network layer processing from a previous hop node, and the
device further comprises: a network layer level transfer unit for transferring
said another frame to a next hop node by assembling another
packet from said another frame and applying the network
layer processing to said another packet.
Claim 3
Dependent Claim
105 words
The router device of claim 2, wherein each frame
received by the receiving unit has an information having
different values for a first type frame to be transferred
by the datalink layer level switching and a second type
frame to be transferred via the network layer processing,
and the device further comprises: a judging unit for judging whether each frame received
by the receiving unit is the first type frame or the second
type frame according to said information, and sending the
first type frame to the datalink layer level transfer unit
while sending the second type frame to the network layer
level transfer unit.
Claim 4
Dependent Claim
34 words
The router device of claim 3, wherein the judging unit
obtains said information by extracting a plurality of bits
at prescribed positions within an address region of each
frame received by the receiving unit.
Claim 5
Dependent Claim
72 words
The router device of claim 1, wherein the memory unit
stores the address information of the next hop node in a
form of a next hop cut-through identifier to be used in
identifying said flow on the datalink layer at the next hop
node, and the datalink layer level transfer unit rewrites
the datalink flow identifier in the prescribed region
according to the next hop cut-through identifier obtained
from the memory unit.
Claim 6
Dependent Claim
33 words
The router device of claim 5, wherein the datalink
layer level transfer unit also rewrites a destination
address of said frame according to the next hop cut-through
identifier obtained from the memory unit.
Claim 7
Dependent Claim
33 words
The router device of claim 5, wherein the datalink
layer level transfer unit also rewrites a source address of
said frame according to the next hop cut-through identifier
obtained from the memory unit.
Claim 8
Dependent Claim
62 words
The router device of claim 5, wherein the next hop
cut-through identifier is formed by another datalink flow
identifier and a cut-through node identifier for
identifying the next hop node or the router device which is
to be used exclusively for a transfer by the datalink layer
level switching and assigned to the next hop node or the
router device in advance.
Claim 9
Dependent Claim
46 words
The router device of claim 5, wherein the next hop
cut-through identifier is stored by exchanging with the
next hop node a message for establishing a correspondence
between the next hop cut-through identifier and a flow
identification information for identifying said flow on a
network layer.
Claim 10
Dependent Claim
82 words
The router device of claim 1, wherein the memory unit
stores the address information of the next hop node in a
form that includes a protocol identification information
for identifying an upper layer protocol of the packet
corresponding to said frame, when the next hop node does
not support transfer by the datalink layer level switching,
and the datalink layer level transfer unit enters the
protocol identification information into the prescribed
region according to the address information obtained from
the memory unit.
Claim 11
Dependent Claim
36 words
The router device of claim 10, wherein the memory unit
stores the address information of the next hop node in a
form that also includes a next hop address fixedly assigned
to the next hop node.
Claim 12
Dependent Claim
64 words
The router device of claim 1, wherein the memory unit
stores the address information of the next hop node in a
form that contains a next hop address fixedly assigned to
the next hop node, when a next hop cut-through identifier
to be used in identifying said flow on the datalink layer
at the next hop node is not known at the router device.
Claim 13
Dependent Claim
78 words
The router device of claim 1, wherein said frame
received by the receiving unit has a destination address
region that contains a cut-through node identifier for
identifying the router device which is to be used
exclusively for a transfer by the datalink layer level
switching and assigned to the router device in advance, and
the datalink layer level transfer unit rewrites the
destination address region of said frame according to the
address information obtained from the memory unit.
Claim 14
Dependent Claim
43 words
The router device of claim 13, wherein the receiving
unit stores the cut-through node identifier of the router
device, and receives an arriving frame when the arriving
frame has the destination address region that contains the
cut-through node identifier of the router device.
Claim 15
Dependent Claim
80 words
The router device of claim 14, further comprising: a unit for transmitting a frame having a source
address region that contains the cut-through node
identifier of the router device toward the previous hop
node when a datalink switch for routing frames according to
destination addresses exists between the router device and
the previous hop node, so as to enable the datalink switch
to route the frames according to destination addresses that
contain the cut-through node identifier of the router
device.
Claim 16
Dependent Claim
88 words
The router device of claim 1, wherein said frame
received by the receiving unit has a source address region
that contains a cut-through node identifier for identifying
the router device or the previous hop device which is to be
used exclusively for a transfer by the datalink layer level
switching and assigned to the router device or the previous
hop device in advance, and the datalink layer level
transfer unit rewrites the source address region of said
frame according to the address information obtained from
the memory unit.
Claim 17
Dependent Claim
101 words
The router device of claim 16, wherein the memory unit
stores the address information of the next hop node in a
form of a next hop cut-through identifier to be used in
identifying said flow on the datalink layer at the next hop
node and a next hop node address, and the datalink layer
level transfer unit rewrites the source address region and
the datalink flow identifier in the prescribed region
according to the next hop cut-through identifier obtained
from the memory unit while rewriting a destination address
region according to the next hop node address obtained from
the memory unit.
Claim 18
Dependent Claim
68 words
The router device of claim 1, wherein the memory unit
stores the correspondence in terms of a cut-through
identifier formed by the datalink flow identifier and a
cut-through node identifier for identifying the router
device or the previous hop node which is to be used
exclusively for a transfer by the datalink layer level
switching and assigned to the router device or the previous
hop node in advance.
Claim 19
Dependent Claim
42 words
The router device of claim 18, wherein the cut-through
identifier is stored by exchanging with the previous hop
node a message for establishing a correspondence between
the cut-through identifier and a flow identification
information for identifying said flow on a network layer.
Claim 20
Independent Claim
219 words
A method of frame transfer at a router device,
comprising the steps of: (a) storing a correspondence of a datalink flow identifier
for identifying each flow on a datalink layer and an
address information of a next hop node to which frames of
packets belonging to each flow are to be transferred next
in a memory of the router device; (b) receiving a frame to be transferred by a datalink
layer level switching, said frame having the datalink flow
identifier for identifying a flow of a packet corresponding
to said frame on the datalink layer, the datalink flow
identifier being contained in a prescribed region of said
frame corresponding to an upper layer protocol
identification information region of a frame format for
frames to be transferred via a network layer processing; and (c) transferring said frame received from a previous hop
node belonging to one logical network by the step (a) to
the next hop node belonging to another logical network, by
obtaining the address information of the next hop node by
referring to the correspondence stored by the memory using
at least the datalink flow identifier contained in said
prescribed region of said frame as a key, and by attaching
the address information of the next hop node to said frame,
without carrying out the network layer processing.
Claim 21
Dependent Claim
62 words
The method of claim 20, wherein the step (b) also
receives another frame to be transferred via the network
layer processing from a previous hop node, and the method
further comprises the step of: (d) transferring said another frame to a next hop node by
assembling another packet from said another frame and
applying the network layer processing to said another
packet.
Claim 22
Dependent Claim
98 words
The method of claim 21, wherein each frame received by
the step (b) has an information having different values for
a first type frame to be transferred by the datalink layer
level switching and a second type frame to be transferred
via the network layer processing, and the method further
comprises the step of: (e) judging whether each frame received by the step (b) is
the first type frame or the second type frame according to
said information, and sending the first type frame to the
step (c) while sending the second type frame to the step
(d).
Claim 23
Dependent Claim
33 words
The method of claim 22, wherein the step (e) obtains
said information by extracting a plurality of bits at
prescribed positions within an address region of each frame
received by the step (b).
Claim 24
Dependent Claim
67 words
The method of claim 20, wherein the step (a) stores
the address information of the next hop node in a form of a
next hop cut-through identifier to be used in identifying
said flow on the datalink layer at the next hop node, and
the step (c) rewrites the datalink flow identifier in the
prescribed region according to the next hop cut-through
identifier obtained from the memory.
Claim 25
Dependent Claim
28 words
The method of claim 24, wherein the step (c) also
rewrites a destination address of said frame according to
the next hop cut-through identifier obtained from the
memory.
Claim 26
Dependent Claim
28 words
The method of claim 24, wherein the step (c) also
rewrites a source address of said frame according to the
next hop cut-through identifier obtained from the memory.
Claim 27
Dependent Claim
61 words
The method of claim 24, wherein the next hop cut-through
identifier is formed by another datalink flow
identifier and a cut-through node identifier for
identifying the next hop node or the router device which is
to be used exclusively for a transfer by the datalink layer
level switching and assigned to the next hop node or the
router device in advance.
Claim 28
Dependent Claim
45 words
The method of claim 24, wherein the next hop cut-through
identifier is stored by exchanging with the next
hop node a message for establishing a correspondence
between the next hop cut-through identifier and a flow
identification information for identifying said flow on a
network layer.
Claim 29
Dependent Claim
77 words
The method of claim 20, wherein the step (a) stores
the address information of the next hop node in a form that
includes a protocol identification information for
identifying an upper layer protocol of the packet
corresponding to said frame, when the next hop node does
not support transfer by the datalink layer level switching,
and the step (c) enters the protocol identification
information into the prescribed region according to the
address information obtained from the memory.
Claim 30
Dependent Claim
35 words
The method of claim 29, wherein the step (a) stores
the address information of the next hop node in a form that
also includes a next hop address fixedly assigned to the
next hop node.
Claim 31
Dependent Claim
63 words
The method of claim 20, wherein the step (a) stores
the address information of the next hop node in a form that
contains a next hop address fixedly assigned to the next
hop node, when a next hop cut-through identifier to be used
in identifying said flow on the datalink layer at the next
hop node is not known at the router device.
Claim 32
Dependent Claim
73 words
The method of claim 20, wherein said frame received by
the step (b) has a destination address region that contains
a cut-through node identifier for identifying the router
device which is to be used exclusively for a transfer by
the datalink layer level switching and assigned to the
router device in advance, and the step (c) rewrites the
destination address region of said frame according to the
address information obtained from the memory.
Claim 33
Dependent Claim
48 words
The method of claim 32, further comprising the step
of: (f) storing the cut-through node identifier of the router
device, so that the step (b) receives an arriving frame
when the arriving frame has the destination address region
that contains the cut-through node identifier of the router
device.
Claim 34
Dependent Claim
80 words
The method of claim 33, further comprising the step
of: (g) transmitting a frame having a source address region
that contains the cut-through node identifier of the router
device toward the previous hop node when a datalink switch
for routing frames according to destination addresses
exists between the router device and the previous hop node,
so as to enable the datalink switch to route the frames
according to destination addresses that contain the cut-through
node identifier of the router device.
Claim 35
Dependent Claim
83 words
The method of claim 20, wherein said frame received by
the step (b) has a source address region that contains a
cut-through node identifier for identifying the router
device or the previous hop device which is to be used
exclusively for a transfer by the datalink layer level
switching and assigned to the router device or the previous
hop device in advance, and the step (c) rewrites the source
address region of said frame according to the address
information obtained from the memory.
Claim 36
Dependent Claim
95 words
The method of claim 35, wherein the step (a) stores
the address information of the next hop node in a form of a
next hop cut-through identifier to be used in identifying
said flow on the datalink layer at the next hop node and a
next hop node address, and the step (c) rewrites the source
address region and the datalink flow identifier in the
prescribed region according to the next hop cut-through
identifier obtained from the memory while rewriting a
destination address region according to the next hop node
address obtained from the memory.
Claim 37
Dependent Claim
67 words
The method of claim 20, wherein the step (a) stores
the correspondence in terms of a cut-through identifier
formed by the datalink flow identifier and a cut-through
node identifier for identifying the router device or the
previous hop node which is to be used exclusively for a
transfer by the datalink layer level switching and assigned
to the router device or the previous hop node in advance.
Claim 38
Dependent Claim
41 words
The method of claim 37, wherein the cut-through
identifier is stored by exchanging with the previous hop
node a message for establishing a correspondence between
the cut-through identifier and a flow identification
information for identifying said flow on a network layer.
References Cited (Backward Citations)
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