Abstract: A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g., the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronisation of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit.

Abstract: A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g., the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronisation of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit.

Abstract: A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g. the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronization of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit.

Abstract: A network unit comprises a multiplicity of ports for transmitting and receiving data packets, a bridging facility and a routing facility. The network unit has a multiplicity of mutually exclusive states which includes an initial state from which said network unit can transition to either a slave state; or a waiting state from which in the absence of receipt from elsewhere of a broadcast advertisement including an advertised address corresponding to an address of the unit, the unit transitions to a master routing state in which the routing facility is enabled and the unit broadcasts a corresponding advertisement including an address of the unit. The unit transitions from the waiting state, when it receives from elsewhere (i.e., another unit) such a broadcast advertisement, to a master bridging state in which the routing facility is disabled and the unit provides commands for disabling a routing facility of other similar units to which the network is connected.

Abstract: A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g. the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronisation of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit.

Abstract: A network unit comprises a multiplicity of ports for transmitting and receiving data packets, a bridging facility and a routing facility. The network unit has a multiplicity of mutually exclusive states which include an initial state from which said network unit can transition to either a slave state; or a waiting state from which in the absence of receipt from elsewhere of an broadcast advertisement including an advertised address corresponding to an address of the unit, the unit transitions to a master routing state in which the routing facility is enabled and the unit broadcasts a corresponding advertisement including an address of the unit. The unit transitions from the waiting state, when it receives from elsewhere (i.e. another unit) such a broadcast advertisement, to a master bridging state in which the routing facility is disabled and the unit provides commands for disabling a routing facility of other similar units to which the network unit is connected.