Flooding reduction method
First Claim
1. A MAC (media access control) frame transfer method for reducing a flooding in a backbone network with which a plurality of customer local area networks are connected via respective edge bridges which each comprise at least one customer port and at least one backbone port to realize a VLAN (virtual local area network), the method comprising the steps of:
- receiving a MAC frame from one of said customer local area networks via said at least one customer port of each edge bridge;
identifying a service VLAN ID for said MAC frame from a customer port which received said MAC frame;
obtaining a destination group ID for identifying a combination of a source of said MAC frame and at least one destination;
on the basis of said obtained destination group ID, judging whether said at least one backbone port includes one which is to transfer said MAC frame;
if said at least one backbone port includes at least one backbone port which is to transfer said MAC frame, forming a backbone MAC frame which includes said MAC frame and said service VLAN ID;
setting said destination group ID in said backbone MAC frame; and
transferring said backbone MAC frame with said destination group ID set to said at least one backbone port which is to transfer said MAC frame.
1 Assignment
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Accused Products
Abstract
In receiving a MAC (media access control) frame whose destination address is any of a broadcast address, an unknown multicast address and an unknown unicast address, the flooding is reduced by broadcasting the received MAC frame to all the other ports than one that has received the MAC frame. An output control that attains this object is realized by using a destination group identifier (ID) look-up table (2-T1) which enables a look-up of a destination group ID by using, as a key, any one or combination of header information of the MAC frame, a port which received the MAC frame and a service VLAN (virtual local area network) ID corresponding to the MAC frame and a backbone port look-up table (2-T2) which enables a look-up of at least one backbone port which is to transmit or at least one backbone port which is not to transmit by using the destination group ID as a key.
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Citations
36 Claims
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1. A MAC (media access control) frame transfer method for reducing a flooding in a backbone network with which a plurality of customer local area networks are connected via respective edge bridges which each comprise at least one customer port and at least one backbone port to realize a VLAN (virtual local area network), the method comprising the steps of:
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receiving a MAC frame from one of said customer local area networks via said at least one customer port of each edge bridge; identifying a service VLAN ID for said MAC frame from a customer port which received said MAC frame; obtaining a destination group ID for identifying a combination of a source of said MAC frame and at least one destination; on the basis of said obtained destination group ID, judging whether said at least one backbone port includes one which is to transfer said MAC frame; if said at least one backbone port includes at least one backbone port which is to transfer said MAC frame, forming a backbone MAC frame which includes said MAC frame and said service VLAN ID; setting said destination group ID in said backbone MAC frame; and transferring said backbone MAC frame with said destination group ID set to said at least one backbone port which is to transfer said MAC frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A flooding reduction method in an edge bridge comprising at least one customer port which receives and transmits a MAC frame from and to a customer site and which has at least one service VLAN (virtual local area network) ID (identifier) preset so that a MAC frame received from one of said at least one customer port is associated with a service VLAN ID for said one of said at least one customer port;
- at least one backbone port for receiving and transmitting a backbone MAC frame from and to a backbone network;
a destination group ID look-up table which enables a look-up of a destination group ID by using, as a key, any one or combination of a part or an entirety of header information of said MAC frame, a port which received said MAC frame and a service VLAN ID corresponding to said MAC frame; and
a backbone port look-up table which enables a look-up of at least one backbone port which is to transmit or at least one backbone port which is not to transmit by using, as a key, a destination group ID for identifying a set of destinations to which said backbone MAC frame is to be transferred, wherein said backbone MAC frame at least includes said MAC frame, said service VLAN ID corresponding to said MAC frame, a source address corresponding to a source and a destination address corresponding to a destination in said backbone network, wherein if user data is encapsulated in said MAC frame received through a customer port, said MAC frame is transferred to a MAC relay portion, which either executes a first relay process in which if there exists at least one customer port other than a recipient of said MAC frame which at least one customer port corresponds to said service VLAN ID corresponding to said MAC frame, then said MAC frame is transferred to said at least one customer port and/or a second relay process in which if there exist at least one backbone port which is to transfer a backbone MAC frame which contains said MAC frame and the service VLAN ID corresponding to said MAC frame, then said MAC frame is transferred to said at least one backbone port, or otherwise discards said MAC frame, wherein if said backbone MAC frame is received from one of said at least one backbone port and if said received backbone MAC frame contains said MAC frame in which the user data is encapsulated, then said backbone MAC frame is passed to said MAC relay portion, which either executes a third relay process in which if there exists at least one customer port which corresponds to a service VLAN ID corresponding to said MAC frame, said MAC frame is transferred to said at least one customer port and/or a fourth relay process in which if there exists at least one backbone port other than a recipient of said backbone MAC frame which at least one backbone port is to transfer said backbone MAC frame, then said MAC frame is transferred to said at least one backbone port, or otherwise discards said backbone MAC frame, and wherein as a destination to which said MAC frame is transferred, any of a destination backbone port, a destination customer port, a destination edge bridge and a destination MAC address is used, the flooding reduction method comprising the steps, executed by said edge bridge, of;if said edge bridge receives said MAC frame from one of said at least one customer port, searching said destination group ID look-up table for said destination group ID by using, as a key, any one or combination of a part or an entirety of header information of said MAC frame, the port which received said MAC frame and the service VLAN ID corresponding to said MAC frame (a destination group ID look-up step); if said destination group ID is found in said destination group ID look-up step and said MAC relay portion transfers said MAC frame to at least one backbone port, setting said found destination group ID in a predetermined field of a backbone MAC frame which contains a service VLAN ID corresponding to said MAC frame (a destination group ID setting step); searching said backbone port look-up table for at least one backbone port by using said found destination group ID as a key (a backbone port look-up step); and if at least one backbone port which is to transmit is found in said backbone port look-up step, enabling said backbone MAC frame to be transmitted to said at least one backbone port and, otherwise, disabling said backbone MAC frame to be transmitted to said at least one backbone port. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
- at least one backbone port for receiving and transmitting a backbone MAC frame from and to a backbone network;
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29. An edge bridge for correcting a customer LAN (local area network) to a backbone network so that customer LANs constitute a virtual IAN (VLAN), comprising:
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at least one customer port for each communicating a MAC (media access control) frame with said customer LAN; a destination group ID look-up table in which at least one of at least a part of header information of said MAC frame, a customer port which received said MAC frame and a service VLAN ID for said MAC frame is recorded in association with a destination group ID for identifying a combination of a source of said MAC frame and at least one destination of said MAC frame so as to enable searching and alteration thereof; a backbone port look-up table in which each destination group ID is recorded in association with at least one backbone port and information on whether each of said at least one backbone port is capable of relaying said backbone MAC frame corresponding to said destination group ID so as to enable searching and alteration thereof; a destination group ID look-up module, operative in case of receiving said MAC frame from one of said at least one customer port, for looking up a destination group ID in said destination group ID look-up table by using as the key at least one or any combination of at least a part of said header information of said MAC frame, a customer port which received said MAC frame and a service VLAN ID corresponding to said MAC frame; a backbone port look-up module, responsive to a finding of said destination group ID by said destination group ID look-up module, for searching, with said destination group ID, said backbone port look-up table for one or more of said at least one backbone port which is to transfer said MAC frame; transmission control module, operative in the event that said one or more backbone ports are found in said at least one backbone port by said backbone port look-up mo which is to transfer said MAC frame dule, for making said one or more backbone ports in a transmission-enable state and making remaining backbone ports in a transmission-disable state; a MAC relay portion for identifying a service VLAN ID corresponding to said MAC frame from said customer port which received said MAC frame, forming a backbone MAC frame which at least includes said MAC frame and said service VLAN ID, and transferring said backbone MAC frame to said one or more backbone ports found by said backbone port look-up module; and a destination group ID setting module for setting said destination group ID looked up by said destination group ID look-up module to said backbone MAC frame to be transferred to said one or more backbone ports by said MAC relay portion. - View Dependent Claims (30, 31, 32)
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33. A system for reducing the flooding, in said backbone network, of a virtual LAN realized by connecting a plurality of customer LANs with said backbone network via respective edge bridges, each of said edge bridges comprising:
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a destination group ID look-up table which enables a look-up of a destination group ID by using, as a key, any one or combination of a part or an entirety of header information of a MAC frame, a port which received said MAC frame and a service VLAN ID corresponding to said MAC frame; a backbone port look-up table which enables a look-up of at least one backbone port which is to transmit or at least one backbone port which is not to transmit by using said destination group ID as a key; a destination group ID look-up means, responsive to a reception of said MAC frame from a customer port, for looking up a destination group ID in said destination group ID look-up table by using as a key at least one or any combination of the header information of said MAC frame, a port which received said MAC frame and a service VLAN ID corresponding to said MAC frame; a destination group ID setting means, operative in the event that any destination group ID is looked up and said MAC frame is transferred to one or more backbone ports by a MAC relay portion, for setting the looked-up destination group ID to a predetermined field in a backbone MAC frame which includes a service VLAN ID corresponding to said MAC frame; a backbone port look-up means for looking up a backbone port in said backbone port look-up table by using the looked-up destination group ID as the key; and a transmission control means, operative in the event that one or more backbone ports which are to transmit are found by said backbone port look-up means, for enabling a transmission of said backbone MAC frame to the found backbone port(s) and, operative in the event that one or more backbone ports which are not to transmit are found by the backbone port look-up means, for disabling the transmission of said backbone MAC frame to the found backbone port(s). - View Dependent Claims (34, 35, 36)
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Specification