Stacked network routers
Assignee3Com Corporation
InventorsRaphael J. Weyman, Maurice A. Goodfellow
Life of this patent
Estimating the term…
Abstract
A cascaded stack of routing units each of which routes packets that it receives at its external ports and which conduct an election for a lead router that lends network and media access control addresses to the router interfaces of the other units in the stack. These other subordinate units have selected ancillary functions suppressed but otherwise have full routing capability. A packet entering the stack and requiring routing is routed by the unit that receives it and is thereafter bridged to its egress port.
Claims14
A stack comprising a plurality of network units and a cascade connection between the network units, each network unit comprising:
- a) a multiplicity of external ports at which addressed packets can be received and from which packets can be forwarded;
- b) at least one cascade port for sending packets to and receiving packets from a cascade connection to other network units;
- c) a router which is responsive to network protocol data in a received packet to determine a subsequent route for said received packet, said router having means defining a network (IP) address for use in routing said packets;
- and
- d) at least one bridge responsive to media access control addresses in said packets to convey packets between said router and said ports;
- wherein each of the routers operate to route packets received at any one of the multiplicity of external ports of the respective network unit and such packets are thereafter bridged by at least one of the bridges to at least one external port by which such packets leave the stack;
- and
- wherein the router of one of the said network units operates in a lead mode wherein it sends its network address for use by the routers in each other network unit in the stack.
A network unit for use in a stack of network units having a cascade connection between the network units, the network unit comprising:
- a) a multiplicity of external ports at which addressed packets can be received and from which packets can be forwarded;
- b) at least one cascade port for sending packets to and receiving packets from the cascade connection to other network units;
- c) a router which is responsive to network protocol data in a received packet to determine a subsequent route for said received packet, said router having means defining a network (IP) address for use in routing said packets;
- and
- d) at least one bridge responsive to media access control addresses in said packets to convey packets between said router and said ports and to convey packets received at said cascade port to said external ports
- wherein said network unit is operative:
- (i) to participate in a predetermined election for determining which single one of the network units shall have its router in the lead mode;
- (ii) to assume said lead mode if the network unit wins said election and to assume a subordinate mode otherwise
- (iii) when in said lead mode to send a network address for use by the routers in each other network unit in the stack;
- and
- (iv) when in said subordinate mode to receive a substitute network address from another network unit in the stack.
A network unit for use in a stack of network units having a cascade connection between the network units, the network unit comprising:
- a) a multiplicity of external ports at which addressed packets can be received and from which packets can be forwarded;
- b) at least one cascade port for sending packets to and receiving packets from the cascade connection to other network units;
- c) a router which is responsive to network protocol data in a received packet to determine a subsequent route for said received packet, said router having means defining a network (IP) address for use in routing said packets;
- and
- d) at least one bridge responsive to media access control addresses in said packets to convey packets between said router and said ports and to convey packets received at said cascade port to said external ports
- wherein said network unit is operative:
- (i) to participate in a predetermined election for determining which single one of the network units shall have its router in the lead mode;
- (ii) to assume said lead mode if the network unit wins said election and to assume a subordinate mode otherwise
- (iii) when in said lead mode to send a network address for use by the routers in each other network unit in the stack;
- and
- (iv) when in said subordinate mode to receive a substitute network address from another network unit in the stack;
- and
- (v) when in said subordinate mode to suppress selected ancillary functions including the provision of routing information packets and responses to ARP (address resolution protocol) requests.
Dependencies are inferred from the claim text.