Connection-Oriented Communications Scheme For Connection-Less Communications Traffic

• US 20080049621A1
• Filed: 12/30/2005
• Published: 02/28/2008
• Est. Priority Date: 12/31/2004
• Status: Abandoned Application

• Current Assignee: British Telecommunications PLC (BT Group PLC)
• Original Assignee: British Telecommunications PLC (BT Group PLC)
• Inventors: Reid, Andrew, McGuire, Alan
• Application Number:
  US11/794,152
• Publication Number:
  US 20080049621A1
• Time in Patent Office: Days
• US Class Current: 370/236.2
• CPC Class Codes: H04L 12/4645 Details on frame tagging routing of packets H04L45/00; support for virtual LAN H04L49/354
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6486 Signalling Protocols
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
• CPC Class Codes: H04L 41/344 Out-of-band transfers

Abstract

A communications scheme for configuring a network comprising a plurality of connected switching apparatus, each switching apparatus having functionality for implementing connectionless forwarding of received communications traffic to selectively provide a connection-oriented service for said received communications traffic, the scheme comprising: determining in a control plane index header field values to identify connectionless traffic received at switching apparatus for which a connection is to be established between a source node and a destination node; providing each switching apparatus necessary to implement the connection with information from the control plane, the information enabling the data forwarding tables of the switching to be populated with said index header field values in association with egress ports of the switching apparatus; and disabling all other functionality on said switching apparatus capable of populating the data forwarding tables with index information associated with said egress ports of the switching apparatus necessary to establish said connection.

Claims

1-111. -111. (canceled)

112. A switching apparatus in a communications network, the switching apparatus comprising:

a plurality of ingress ports arranged to receive traffic in the form of protocol data units which conform to a connection-less communications protocol;

a plurality of egress ports for forwarding received traffic on;

interface means arranged to receive information from a control plane processor; and

data storage means, whereby information provided by the control plane is stored and arranged to associate an egress port of the switching apparatus with an index field,

wherein the information received by the switching apparatus from the control plane enables the switching apparatus to operate to provide a connection-oriented mode of transport for the received traffic to establish a connection between a source node and an end node in said communications network via a plurality of other switching apparatus configured by the control plane, wherein said switching apparatus has no other functionality capable of controlling the data forwarding function for the interfaces of said switching apparatus configured by said control plane to provide a connection-oriented mode of transport for said received traffic, wherein the mode of transport for received traffic between said source and said destination is determinable by the control plane for the plurality of switching apparatus in the communications network.

113. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic.

114. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic.

115. A switching apparatus as claimed in claim 113, wherein the plurality of index field identifiers are arranged in a hierarchical order, and index field identifiers at different levels of the hierarchy are associated with different egress ports of the switch arrangement.

116. A switching apparatus as claimed in claim 112, wherein the information received from the control plane processor further controls the data filtering function the switching apparatus performs on received traffic, and wherein said switching apparatus has no other functionality capable of controlling the data filtering function for the interfaces of said switching apparatus for which the control plane has provided information to control the data filtering function.

117. A switching apparatus as claimed in claim 112, wherein the forwarding and/or filtering functions performed by the switching apparatus are controlled by the control plane populating the forwarding tables used by the switching apparatus to cause said received traffic to follow one or more predetermined paths through said communications network.

118. A switching apparatus as claimed in claim 112, wherein the forwarding and/or filtering functions performed by the switching apparatus are controlled by the control plane populating the forwarding tables used by the switching apparatus to cause said received traffic to follow one or more predetermined paths through said communications network, and wherein said forwarding table has entries causing said received traffic to be forwarded using a connection-oriented mode which take precedence over entries for connectionless traffic.

119. A switching apparatus as claimed in claim 112, wherein the received traffic comprises Ethernet frames or IP packets.

120. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus.

121. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, and wherein said aggregate address information comprises at least one locally unique address and at least one globally unique address, and wherein said control plane provides information to route said received traffic to a globally unique address along a path dependent on one or more locally unique addresses.

122. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, and wherein said aggregate address information comprises information extracted from one or more fields in a header of a packet received by said switching apparatus which is associated with an egress port of the switching apparatus by said control plane, whereby the switching apparatus is arranged to forward said received frame to an egress port of the switching apparatus based on one or more of the following fields of the received packet conforming to a connectionless communications protocol:

one or more destination address fields;

one or more source address fields;

one or more source route address fields;

one or more Ethertype field;

one or more priority fields;

one or more type of service fields;

one or more flow identifier fields; and

one or more fields capable of identifying a virtual private network;

one or more protocol fields;

one or more TCP/UDP destination port identifier fields;

one or more TCP/UDP source port identifier fields.

123. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, and wherein said traffic comprises IP packets and said aggregate address comprises a set of IP addresses and appropriate address mask information associated with an egress port of the switching apparatus, and wherein for each aggregate address, an IP subnet provides a destination address and the address within each subnet uniquely identifies a path through said communications network.

124. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, and wherein said globally significant address is provided by a combination of data stored in the header fields of said received traffic, and wherein said locally significant aggregate address information comprises a hardware address.

125. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, wherein said control plane provides in addition to said address aggregate a unique path identifier comprising a TCP/UDP port identifier associated with an IP address, said TCP/UDP port identifier being associated by the control plane with an egress port of said switching apparatus.

126. A switching apparatus as claimed in claim 112, wherein the mode of transport is determined by the control plane populating the data storage means with a plurality of different index field identifiers, at least one index field identifier comprising a destination address of the connection to be established for said received traffic, and, wherein for one or more egress ports of the switching apparatus, the information provided by the control plane populates the data forwarding table with aggregate address information comprising a combination of header field values associated with an egress port of the switching apparatus, wherein said control plane provides said forwarding table with an IPv6 route associated with an egress port of said switching apparatus, and said unique path identifier comprises said flow identifier of an IPv6 address.

127. A switching apparatus as claimed in claim 112, wherein the connectionless protocol comprises Ethernet.

128. A switching apparatus as claimed in claim 112, wherein the connectionless protocol comprises Ethernet and wherein said locally unique address information comprises one or more MAC header fields.

129. A switching apparatus as claimed in claim 112, wherein the switching apparatus is arranged to be capable of re-activating the connection-less mode of operation of egress ports by activating functionality which is capable of configuring the data forwarding tables of the switching apparatus to operate in a connectionless mode upon receipt of appropriate signalling from the control plane.

130. A switching apparatus as claimed in claim 112, further comprising:

means to extract header information from the header of each received packet;

means to perform a lookup operation to determine if said extracted header information matches stored forwarding information, said forwarding information being arranged to provide a data forwarding function for each said received packet dependent said extracted header information;

wherein said information received from said control plane source is processed by said switching apparatus to populate said data storage means to store forwarding information to enable the control plane source to control the connection-oriented data forwarding functionality which the switching apparatus performs on each said received packet.

131. A switching apparatus as claimed in claim 112, wherein said switching apparatus is deployed in a communications network, and previously provided only a connectionless service over said communications network.

132. A switching apparatus as claimed in claim 112, wherein said switching apparatus provides a transparent point-to-point service over said communications network.

133. A switching apparatus as claimed in claim 112, wherein said switching apparatus provides a transparent point-to-multipoint service over said communications network.

134. A switching apparatus as claimed in claim 131, wherein a field in a header of a packet received by said switching apparatus is associated with an egress port of the switching apparatus, and the switching apparatus forwards said received frame to an egress port of the switching apparatus based on one or more of the following fields of the received packet conforming to a connectionless communications protocol:

one or more destination address fields;

one or more source address fields;

one or more source route address fields;

one or more Ethertype field;

one or more priority fields;

one or more type of service fields;

one or more flow identifier fields; and

one or more fields capable of identifying a virtual private network;

one or more protocol fields;

one or more TCP/UDP destination port identifier fields;

one or more TCP/UDP source port identifier fields.

135. A switching apparatus as claimed in claim 131, wherein a field in a header of a packet received by said switching apparatus is associated with an egress port of the switching apparatus, and the switching apparatus forwards said received frame to an egress port of the switching apparatus based on one or more of the following fields of the received packet conforming to a connectionless communications protocol:

one or more destination address fields;

one or more source address fields;

one or more source route address fields;

one or more Ethertype field;

one or more priority fields;

one or more type of service fields;

one or more flow identifier fields; and

one or more fields capable of identifying a virtual private network;

one or more protocol fields;

one or more TCP/UDP destination port identifier fields;

one or more TCP/UDP source port identifier fields, and

wherein said switching apparatus encapsulates received the header of a received packet within one or more other headers.

136. A switching apparatus as claimed in claim 131, wherein a field in a header of a packet received by said switching apparatus is associated with an egress port of the switching apparatus, and the switching apparatus forwards said received frame to an egress port of the switching apparatus based on one or more of the following fields of the received packet conforming to a connectionless communications protocol:

one or more destination address fields;

one or more source address fields;

one or more source route address fields;

one or more Ethertype field;

one or more priority fields;

one or more type of service fields;

one or more flow identifier fields; and

one or more fields capable of identifying a virtual private network;

one or more protocol fields;

one or more TCP/UDP destination port identifier fields;

one or more TCP/UDP source port identifier fields. and

wherein said switching apparatus encapsulates received the header of a received packet within one or more other headers, wherein said received packet comprises an IP packet having an IP packet header including first IP address information encapsulated in a second IP packet header comprising second IP address information.

137. A switching apparatus as claimed in claim 112, wherein information relating to a connection provided by said switching apparatus in said communications network is provided only within the control plane of said communications network.

143. A control plane processor arranged to provide switching apparatus as claimed in claim 112 with control data, the control data enabling the switching apparatus to implement its data forwarding and data filtering functionality on received packets.

144. A communications network comprising a plurality of interconnected switching apparatus as claimed in claim 112.

145. A communications network comprising a plurality of interconnected switching apparatus as claimed in claim 112, wherein the control data generated by said control plane is transmitted out of band to each switching apparatus.

146. A communications network comprising a plurality of interconnected switching apparatus as claimed in claim 112, wherein the control plane of said communications network establishes a plurality of paths for a traffic flow from at least one data source to at least one data sink through said network.

138. A method of modifying switching apparatus deployed in a communications network to provide a connectionless service over said communications network, wherein said method comprises the step of disabling the data forwarding functionality of the switching apparatus from using information calculated from connectionless routing protocols to implement connectionless routing, and wherein said information populating said forwarding table is provided by the control plane of the switching apparatus, wherein said provided information enables the switching apparatus to implement its data forwarding functionality for received packets.

139. A method of modifying switching apparatus as claimed in claim 138, wherein in said step of disabling the data forwarding functionality, the IP addresses of the switching apparatus themselves are retained in each forwarding table in a normal connectionless mode, and wherein the control plane transport and routing protocol including auto-discovery is implemented in a connectionless mode.

140. A method of modifying switching apparatus deployed in a communications network to provide a connectionless service over said communications network, wherein said method comprises the step of preventing data forwarding in connectionless mode by populating the forwarding table with connection-oriented entries which take precedence over connectionless forwarding entries, and wherein said information populating said forwarding table is provided by the control plane of the switching apparatus, wherein said provided information enables the switching apparatus to implement its data forwarding functionality for received packets.

141. A method of switching packets over a communications network comprising a plurality of interconnected switching apparatus, the method comprising:

receiving packets at a switching apparatus connected to said communications network,

forwarding said packets at a switching apparatus by populating a data store arranged to associate information provided in at least one field of the header of a received packet with an egress port of the switching apparatus using information provided by one or more control plane processors associated with the switching apparatus, said one or more control plane processors comprising the control plane of said communications network, whereby the data forwarding and/or route filtering functionality of the switching apparatus are controlled by the control plane of the communications network.

142. A communications network comprising a plurality of switching apparatus interconnected to provide switchable data transport between data sources and data sinks, wherein the data forwarding and data filtering functions each switch apparatus performs on received packets is controlled by a control plane comprising one or more control plane processors, said control plane providing each switch apparatus with control data enabling the switching apparatus to implement its data forwarding and data filtering functionality on received packets, said received packets including header information having address information conforming to a connectionless protocol, said control data enabling said switching apparatus to provide a connection-oriented service for said received packets.

147. A method of generating an end-to-end connection over a communications network comprising a plurality of switching apparatus preconfigured to support a connectionless communications protocols the method comprising the steps of:

reconfiguring the switching apparatus by;

disabling any functionality supporting forwarding a received communications traffic flow using said connectionless communications protocol;

enabling functionality supporting forwarding a received communications traffic flow using a connection-oriented communications protocol;

determining a path for said end-to-end connection from a source to a sink for said traffic flow;

communicating said path via a control interface to provide routing information for said received traffic flow, whereby said enabling functionality forwards said received traffic flow towards said sink across said communications network.

148. In a communications network comprising a plurality of local area networks interconnected by a wide area network, a method of providing differentiated forwarding modes for packetised data received from a first one of said plurality of LANs to a second one of said plurality of LANs, the method comprising:

at a first apparatus arranged to provide data from said first LAN with access to said WAN, performing a look-up operation on a plurality of header fields for said data;

determining if each of said plurality of header fields are associated with routing information stored in a data store populated by the control plane of said first apparatus;

routing said data across said wide area network to a second apparatus arranged to provide access to data from said WAN to said second LAN in accordance with the routing information provided by said control plane.

149. A method as claimed in claim 148, wherein the packetised data comprises a plurality of Ethernet frames, and said plurality of header fields comprise at least a VLAN-ID/DA MAC tuple, and wherein said first and second switching apparatus comprise first and second independent VLAN learning Ethernet switches respectively.

150. A method as claimed in claim 149, wherein the packetised data comprises a plurality of Ethernet frames, and said plurality of header fields comprise at least a VLAN-ID/DA MAC tuple, and wherein said first and second switching apparatus comprise first and second independent VLAN learning Ethernet switches respectively, and wherein the first and second independent VLAN learning Ethernet switching apparatus are interconnected by a contiguous sequence of independent VLAN learning Ethernet switching apparatus arranged to forward received Ethernet frames on locally significant VLAN-IDs to form a unidirectional connection.

151. A method as claimed in claim 148, wherein the packetised data comprises a plurality of Ethernet frames, and said plurality of header fields comprise at least a VLAN-ID/DA MAC tuple, and wherein said first and second switching apparatus comprise first and second independent VLAN learning Ethernet switches respectively, and wherein the first and second independent VLAN learning Ethernet switching apparatus are interconnected by a contiguous sequence of independent VLAN learning Ethernet switching apparatus arranged to forward received Ethernet frames on locally significant VLAN-IDs to form a unidirectional connection, wherein said routing information provided by said control plane further provides a reverse path between said second Ethernet switch and said first Ethernet switch to provide bi-directional connectivity between said first and second Ethernet switching apparatus.

152. A method of configuring switching apparatus to receive management and/or signalling information comprising the steps of:

retaining a broadcast functionality on one or more specific ports of said switching apparatus,

disabling all pre-existing functionality supporting pre-configured connectionless protocols from other ports of said switching apparatus, said other ports being re-configured by information derived from said management and signalling information received on said one or more specific ports to provide one or more connection-oriented modes of transport for traffic received at said other ports, said traffic received at said other ports conforming to a connectionless communications protocol,

whereby, said one or more specific ports of said switching apparatus are configured to logically isolate said received management and/or signalling information from other traffic received by the switching apparatus.

153. A method of configuring switching apparatus as claimed in claim 152, wherein said retained broadcast functionality enables said switching apparatus to forward said received management and signalling traffic in a connection-less manner;

154. A method of configuring switching apparatus as claimed in claim 152, wherein said switching apparatus logically isolates received management and/or signalling information by associating an identifier extracted from the header of a packet or frame carrying said information with said one or more specific ports of said switching apparatus.

155. A communications scheme for configuring a network comprising a plurality of connected switching apparatus, each switching apparatus having functionality for implementing connectionless forwarding of received communications traffic to selectively provide a connection-oriented service for said received communications traffic, the scheme comprising:

determining index header field values to identify traffic received at switching apparatus for which a connection is to be established between a source node and a destination node;

providing each switching apparatus necessary to implement the connection with information which enables their data forwarding tables to be populated with said index header field values in association with egress ports of the switching apparatus; and

disabling all other functionality on said switching apparatus capable of populating the data forwarding tables with index information associated with said egress ports of the switching apparatus necessary to establish said connection.

156. A communications scheme as claimed in claim 155, wherein a plurality of differing types of index header field values are provided by the control plane.

157. A communications scheme as claimed in claim 156, wherein the differing types of index header field values are arranged hierarchically, and different levels of the hierarchy are associated with different egress ports of the switching apparatus.