Dual priority chains for data-communication ports in a multi-port bridge for a local area network
First Claim
1. An apparatus for granting access to a communication bus, the communication bus for interconnecting a plurality of ports in a multi-port bridge for a local area network, the apparatus comprising:
- a. a first plurality of signal lines, one signal line for each port of a first plurality of ports wherein a logic level applied to the signal line for each port of the first plurality is indicative of whether the corresponding port is attempting access to the communication bus; and
b. a first chain circuit coupled to the first plurality of signal lines for determining which of the first plurality of ports is to be granted access to the communication bus, wherein the first chain circuit comprises a first plurality of links, one link for each of the first plurality of ports, wherein each link is selectively configured for passing a first logic signal to a next link according to the logic level of the signal line of the port corresponding to the link.
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Accused Products
Abstract
A technique for prioritizing accesses to a communication bus by data-communication ports in a multi-port bridge for a local area network. The bridge includes a plurality of ports interconnected by the bus. The bus includes signal lines dedicated to communicating commands, signal lines dedicated to communicating data, and several signal lines having special purposes. For example, two signal lines, are preferably dedicated to initiating different types of access to the bus, each having a respective priority. The ports are of two types (e.g. 100 Mbps or 10 Mbps data rates), each having a respective priority. A bus controller monitors the type of access to the bus attempted and the type of ports attempting access and grants access to the bus according to an appropriate priority. Ports of a like type which attempt a like type of access to the communication bus are granted access to the bus according to an assigned relative order, wherein the assigned relative order repeats and wherein a port last granted access to the communication bus has a lowest priority and a port adjacent in the assigned relative order to the last port granted access to the communication bus has a highest priority and remaining ports have ascending intermediate levels of priority according to the assigned relative order. Logic utilized makes a determination of which port is to be granted access to the bus in the appropriate priority with a minimum of delay.
113 Citations
35 Claims
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1. An apparatus for granting access to a communication bus, the communication bus for interconnecting a plurality of ports in a multi-port bridge for a local area network, the apparatus comprising:
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a. a first plurality of signal lines, one signal line for each port of a first plurality of ports wherein a logic level applied to the signal line for each port of the first plurality is indicative of whether the corresponding port is attempting access to the communication bus; and b. a first chain circuit coupled to the first plurality of signal lines for determining which of the first plurality of ports is to be granted access to the communication bus, wherein the first chain circuit comprises a first plurality of links, one link for each of the first plurality of ports, wherein each link is selectively configured for passing a first logic signal to a next link according to the logic level of the signal line of the port corresponding to the link. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for granting access to a communication bus, the communication bus for interconnecting a plurality of ports in a multi-port bridge for a local area network, the apparatus comprising:
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a. a plurality of signal lines, one signal line for each port of the plurality; b. a first circuit coupled to each of the plurality of ports for determining a type of access to the communication bus; c. a second circuit coupled to each of the signal lines for determining a type of port attempting access to the communication bus; and d. a third circuit coupled to the first circuit and to the second circuit for determining which of the plurality of ports is to be granted access to the communication bus, wherein ports of a like type which attempt a like type of access to the communication bus are granted access to the communication bus according to an assigned relative order wherein a port last granted access to the communication bus has a lowest priority and a port adjacent in the assigned relative order to the last port granted access to the communication bus has a highest priority and remaining ports have ascending intermediate levels of priority according to the assigned relative order. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of granting access to a communication bus, the communication bus for interconnecting a plurality of ports in a multi-port bridge for a local area network, the method comprising steps of:
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a. receiving one or more attempts for access to the communication bus from one or more of the ports wherein each attempt is one of a plurality of different types of attempts and each port is one of a plurality of different types of ports; b. determining which of the plurality of ports is to be granted access to the communication bus, wherein each type of attempt has a relative priority and each type of port has a relative priority, wherein ports of a like type which attempt a like type of access to the communication bus are granted access to the communication bus according to an assigned relative order, wherein a port last granted access to the communication bus has a lowest priority and a port adjacent in the assigned relative order to the last port granted access to the communication bus has a highest priority and remaining ports have ascending intermediate levels of priority according to the assigned relative order. - View Dependent Claims (28, 29, 30, 31)
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32. An apparatus for granting access to a communication bus, the communication bus for interconnecting a plurality of ports in a multi-port bridge for a local area network, the apparatus comprising:
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a. means for collecting the plurality of ports into a plurality of groups of ports, wherein each group of ports has a predetermined relative group priority and the ports within each group of ports have a predetermined relative port order; b. means for determining whether any one of the ports is requesting access to the communication bus; c. means for determining a highest current group from among the groups of ports having a port requesting access to the communication bus according to the predetermined relative group priority; d. means for determining when there is more than one port in the highest current group which is requesting access to the communication bus; and e. means for granting access to an accessing requesting port of the highest current group according to the predetermined relative port order, wherein a port last granted access to the communication bus is a last port within the relative port order of the highest current group. - View Dependent Claims (33, 34, 35)
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Specification