CN115277304A - Flow forwarding method and device - Google Patents

Abstract

This specification provides a traffic forwarding method and device, and relates to the technical field of communications. A traffic forwarding method, applied to a first PE of an EVPN, includes: receiving an Ethernet automatic discovery route sent by PEs in different Ethernet segments, wherein the extended community attribute of the Ethernet automatic discovery route carries a designated identifier, and the designated identifier It is used to indicate whether the PE forwards BUM traffic; the specified identifier of the PE is recorded in the forwarding table; if the first PE receives the BUM traffic of the connected client-side edge device CE, the second PE is determined from the forwarding table according to the specified identifier , and forward BUM traffic to the second PE. Through the above method, the bandwidth in the EVPN network can be saved.

Description

A traffic forwarding method and device

technical field

This description relates to the technical field of communications, and in particular to a traffic forwarding method and device.

Background technique

EVPN (Ethernet Virtual Private Network, Ethernet Virtual Private Network) is a VPN (Virtual Private Network, Virtual Private Network) technology used for Layer 2 network interconnection. PE (Provider Edge) forwards data packets by searching the MAC (Media Access Control) address table, and provides users with Layer 2 services from CE (Customer Edge) to CE.

In a multi-homing scenario, a CE is connected to multiple PEs through different Ethernet links. When the source CE sends BUM (Broadcast, Unknown-unicast, Multicast, broadcast, unknown unicast, multicast) traffic to the multi-homed destination CE, the PE connected to the source CE copies the BUM traffic and forwards it to the destination respectively. On multiple PEs connected to the CE, the DF (Designated Forwarder, Designated Forwarder) in these PEs will forward the BUM traffic to the destination CE, and the non-DF will discard the BUM traffic. However, these discarded BUM traffic still occupy the bandwidth in the EVPN network, thus causing a waste of bandwidth.

Contents of the invention

In order to overcome the problems existing in related technologies, this specification provides a traffic forwarding method and device.

In combination with the first aspect of the embodiments of this specification, this application provides a traffic forwarding method, which is applied to the first PE of EVPN, including:

Receive the Ethernet auto-discovery routes sent by PEs in different Ethernet segments, wherein the extended community attribute of the Ethernet auto-discovery routes carries a specified identifier, and the specified identifier is used to indicate whether the PE forwards BUM traffic;

Record the designated ID of the PE in the forwarding table;

If the first PE receives the BUM traffic of the connected customer-side edge device CE, it determines the second PE from the forwarding table according to the specified identifier, and forwards the BUM traffic to the second PE.

Optionally, after recording the specified ID of the PE in the forwarding table, it also includes:

If the first PE receives the known unicast traffic of the connected CE, it forwards the known unicast traffic according to the forwarding table.

Optionally, the specified identifier is located in a reserved field in the extended community attribute of the ESI label of the Ethernet auto-discovery route;

When the specified identifier is set to the first value, it indicates that the PE corresponding to the specified identifier is a PE accessed by DF or CE single-homed access;

When the specified identifier is set to the second value, it indicates that the PE corresponding to the specified identifier is a non-DF for CE multi-homing access.

With reference to the second aspect of the embodiments of this specification, this application provides a traffic forwarding method, which is applied to the second PE of EVPN, including:

Send the Ethernet auto-discovery route with the specified identifier in the extended community attribute to PEs in different Ethernet segments, so that the first PE that records the specified identifier forwards the BUM traffic sent by the CE connected to the first PE according to the specified identifier.

Optionally, send Ethernet auto-discovery routes to PEs in different Ethernet segments, including:

If it is a PE that is single-homed by DF or CE, send the Ethernet auto-discovery route with the specified identifier set as the first value in the extended community attribute to PEs in different Ethernet segments;

If it is a non-DF that is multi-homed by the CE, send the Ethernet auto-discovery route with the specified identifier set as the second value in the extended community attribute to PEs in different Ethernet segments.

With reference to the third aspect of the embodiments of this specification, this application provides a traffic forwarding device, which is applied to the first PE of EVPN, including:

The receiving unit is configured to receive an Ethernet auto-discovery route sent by PEs in different Ethernet segments, wherein the extended community attribute of the Ethernet auto-discovery route carries a specified identifier, and the specified identifier is used to indicate whether the PE forwards BUM traffic;

A recording unit, configured to record the specified identifier of the PE in the forwarding table;

The sending unit is configured to determine the second PE from the forwarding table according to the specified identifier and forward the BUM traffic to the second PE if receiving the BUM traffic of the customer-side edge device CE connected to the first PE.

Optionally, the sending unit is further configured to forward the known unicast traffic according to the forwarding table if receiving the known unicast traffic of the client-side edge device CE connected to the first PE.

Optionally, the specified identifier is located in a reserved field in the extended community attribute of the ESI label of the Ethernet auto-discovery route;

When the specified identifier is set to the first value, it means that the PE corresponding to the specified identifier is a PE that is single-homed by the designated forwarder DF or CE;

When the specified identifier is set to the second value, it indicates that the PE corresponding to the specified identifier is a non-DF for CE multi-homing access.

With reference to the fourth aspect of the embodiments of this specification, this application provides a traffic forwarding device, which is applied to the second PE of EVPN, including:

A sending unit, configured to send an Ethernet auto-discovery route with a specified identifier in the extended community attribute to PEs in different Ethernet segments, so that the first PE that records the specified identifier forwards the CE connected to the first PE according to the specified identifier BUM traffic sent.

Optionally, the sending unit is specifically configured to, if it is a PE that is single-homed by DF or CE, send to PEs in different Ethernet segments the extended community attribute that carries the specified identifier and is set as the first value. Automatically discover routes; if it is a non-DF with CE multi-homing access, send the Ethernet auto-discovery routes with the specified identifier set as the second value in the extended community attribute to PEs in different Ethernet segments.

With reference to the fifth aspect of the embodiments of this specification, this application provides a network device, including a transceiver, a processor, and a machine-readable storage medium, where the machine-readable storage medium stores machine-executable instructions that can be executed by the processor, The processor is caused by the machine-executable instructions to: carry out the method steps of any one of the above.

In conjunction with the sixth aspect of the embodiments of this specification, the present application provides a machine-readable storage medium, which stores machine-executable instructions. When called and executed by a processor, the machine-executable instructions prompt the processor to: implement any of the above-mentioned method steps for the item.

The technical solutions provided by the embodiments of this specification may include the following beneficial effects:

In the embodiment of this specification, the Ethernet auto-discovery routes are exchanged between PEs in multiple Ethernet segments. The Ethernet auto-discovery routes carry forwarding information and designated identifiers, and the designated identifiers can be sent to other Ethernet segments The PE notifies itself whether it can forward BUM traffic to its connected CE, so that PEs in other Ethernet segments can directly forward BUM traffic to the PE that can forward BUM traffic, avoiding bandwidth waste on the EVPN network.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the specification.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate implementations consistent with this specification and together with the description serve to explain the principles of this specification.

FIG. 1 is a flowchart of a traffic forwarding method involved in an embodiment of the present application, which is applied to a first PE;

FIG. 2 is a flow chart of a traffic forwarding method involved in an embodiment of the present application, which is applied to a second PE;

FIG. 3 is a network diagram applicable to a traffic forwarding method involved in an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a traffic forwarding device according to an embodiment of the present application, which is applied to a first PE;

FIG. 5 is a schematic structural diagram of a traffic forwarding device involved in an embodiment of the present application, which is applied to a second PE;

FIG. 6 is a schematic structural diagram of a network device involved in an embodiment of the present application.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. Embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this specification.

This application provides a traffic forwarding method, which is applied to the first PE of EVPN, as shown in Figure 1, including:

S100. Receive automatic Ethernet discovery routes sent by PEs in different Ethernet segments.

In an EVPN network, multiple PEs can establish a BGP neighbor relationship based on the BGP (Border Gateway Protocol, Border Gateway Protocol) protocol.

Thereafter, the PEs can exchange Ethernet segment routes (Ethernet Segment Routes), and the Ethernet segment routes carry the PE's own ESI and source IP (Internet Protocol, Internet Protocol) addresses. Through the ESI and source IP address, a PE can determine the PEs in the same Ethernet segment as itself, and establish a multi-homing PE list. The sequence number is included in the multi-homing PE list, and the PE can elect a DF through the sequence number.

After the PE as the DF is elected, the PE can send out the Ethernet auto-discovery route (Ethernet Auto-discovery Per ES). The extended community attribute (ESI Label ExtendedCommunity) of the Ethernet auto-discovery route carries a specified identifier, and the specified identifier is used to indicate whether the PE forwards BUM traffic.

Alternatively, when a PE determines that it is a PE that is single-homed to the CE, the PE may also send an Ethernet auto-discovery route carrying a specified identifier to the outside.

Optionally, the specified identifier is located in a reserved field (for example, Reserved field) in the extended community attribute of the ESI label of the Ethernet auto-discovery route. For example, the specified flag occupies the first bit of the Reserved field.

In addition, PEs can perform processes such as MAC address learning, and PEs can also exchange forwarding information. The forwarding information includes the PE's IP address, MAC address, and forwarding labels (such as Layer 2 forwarding labels and Layer 3 forwarding labels). A forwarding table based on forwarding information is formed in the PEs, so as to realize cross-backbone network reachability between PEs.

S101. Record the designated ID of the PE in the forwarding table.

After the PE receives the Ethernet auto-discovery route, it can record the specified identifier in the forwarding table.

When the specified identifier is set to the first value (for example, the first bit is set to 1), it indicates that the PE corresponding to the specified identifier is a PE for DF or CE single-homed access;

When the specified identifier is set to the second value (for example, the first bit is set to 0), it indicates that the PE corresponding to the specified identifier is a non-DF for CE multi-homing access.

S102. If the BUM traffic of the CE connected to the first PE is received, determine the second PE from the forwarding table according to the specified identifier, and forward the BUM traffic to the second PE.

In order to save the bandwidth occupied by the BUM traffic on the backbone network in the EVPN network, when the first PE receives the traffic sent by the CE, it determines whether the traffic is BUM traffic. If the traffic is BUM traffic, look up the forwarding table to determine whether there is a record of the PE (that is, DF) that forwards the BUM traffic.

If the PE as the DF has been recorded or associated in the forwarding table, the BUM traffic can be sent to the PE as the DF based on the forwarding information such as the MAC address stored in the forwarding table, so that the first PE sends The CE connected to the second PE at the opposite end forwards the BUM traffic. However, for the non-DF PEs, the first PE will not send the BUM traffic to them.

It should be noted that, if multiple PEs recorded in the first PE are marked with specified identifiers, the first PE may send BUM traffic to the multiple specified PEs respectively.

Optionally, after step S101, after recording the designated ID of the PE in the forwarding table, further include:

S103. If the known unicast traffic of the CE connected to the first PE is received, forward the known unicast traffic according to the forwarding table.

If the first PE receives the traffic sent by the connected CE and determines that the traffic is known unicast traffic according to the packet information in the traffic, the first PE can forward the traffic to the peer PE based on the generated forwarding table. Forward.

Correspondingly, this application provides a traffic forwarding method, which is applied to the second PE of EVPN, as shown in Figure 2, including:

S200. Send the Ethernet auto-discovery route carrying the specified identifier in the extended community attribute to PEs in different Ethernet segments, so that the first PE that records the specified identifier forwards the BUM traffic sent by the CE connected to the first PE according to the specified identifier.

Wherein, the extended community attribute of the Ethernet automatic discovery route carries a specified identifier, and the specified identifier is used to indicate whether the PE forwards the BUM traffic.

Optionally, step S200, sending Ethernet auto-discovery routes to PEs in different Ethernet segments, including:

S200A. If the PE itself is single-homed by the DF or the CE, send the Ethernet auto-discovery route with the specified identifier set as the first value in the extended community attribute to PEs in different Ethernet segments.

S200B. If the non-DF is multi-homed by the CE, send the Ethernet auto-discovery route with the specified identifier set as the second value in the extended community attribute to PEs in different Ethernet segments.

In the embodiment of this specification, the Ethernet auto-discovery routes are exchanged between PEs in multiple Ethernet segments. The Ethernet auto-discovery routes carry forwarding information and designated identifiers, and the designated identifiers can be sent to other Ethernet segments The PE notifies itself whether it can forward BUM traffic to its connected CE, so that PEs in other Ethernet segments can directly forward BUM traffic to the PE that can forward BUM traffic, avoiding bandwidth waste on the EVPN network.

A traffic forwarding method will be described below with reference to a specific implementation manner as an example. The EVPN network, as shown in Figure 3, includes three PEs, PE1, PE2, and PE3, and two CEs, CE1 and CE2. Among them, CE1 and CE2 belong to EVPN1, PE1, PE2, and PE3 are deployed on the backbone network, CE1 mostly belongs to PE1 and PE2, and CE2 only belongs to PE3.

S1 and the CE exchange ARP packets, and the PE records the MAC address/IP address to advertise the route.

CE1, CE2, and CE3 exchange ARP packets. PE1 and PE2 record CE1's MAC address/IP address to advertise routes, and PE3 records CE2's MAC address/IP address to advertise routes.

S2. Multiple PEs exchange MAC addresses/IP addresses to advertise routes, and PE records generate a forwarding table.

A forwarding table is generated in the instance corresponding to EVPN1, and forwarding information such as MAC addresses, IP addresses, and next hops of routings of reachable PEs can be recorded in the forwarding table.

S3. After the neighbor relationship is established between the multiple PEs, the multiple PEs exchange Ethernet segment routes, create a multi-homing PE list, and interact and integrate multicast routes.

Through the exchange of Ethernet segment routes, PE1 and PE2 can determine that they belong to the same Ethernet segment according to the ESI carried in the exchanged Ethernet segment routes, and generate a multi-homed PE list, and record in the multi-homed PE list There are sequence numbers of multiple PEs belonging to the same Ethernet segment.

Both PE1 and PE2 belong to ESI1, therefore, a multi-homed PE list can be generated on PE1 and PE2

, the sequence number of PE1 is set to 0, and the sequence number of PE2 is set to 1. PE3 belongs to ESI2, but due to

ESI2 does not contain other PEs, therefore, no multi-homed PE list is generated in PE3.

After the neighbor relationship is established between multiple PEs, the PEs will also interact with an integrated multicast route (InclusiveMulticast Route), so as to determine the PEs belonging to the same EVPN in the networking. For example, multiple PEs can determine that PE1, PE2, and PE3 belong to EVPN1.

In addition, in integrated multicast routing, information such as IP addresses and tunnel labels of PEs can also be exchanged.

S4. Elect a DF from the PEs belonging to the same Ethernet segment.

The election is performed between PE1 and PE2, and based on the sequence numbers recorded in the multi-homed PE lists of PE1 and PE2, it can be determined that PE1 is elected as the DF.

S5. The PEs exchange automatic Ethernet discovery routes, and the reserved field in the extended community attribute of the Ethernet automatic discovery routes carries an indication identifier.

When exchanging Ethernet auto-discovery routes among PE1, PE2, and PE3, PE1 is selected as the DF, and CE2 is single-homed to PE3. Therefore, when PE1 and PE3 send Ethernet auto-discovery routes, the indicator in the extended community attribute The first bit of the indicator in the extended community attribute is set to 1, and when PE2 sends an Ethernet auto-discovery route, the first bit of the indicator in the extended community attribute is set to 0.

PE1 and PE2 can record the indication identifier carried in the Ethernet auto-discovery route sent by PE3 in the forwarding table to determine that PE3 can forward the BUM traffic to CE2, and PE3 can record the routing information sent by PE1 and PE2 in the forwarding table. The Ethernet automatically discovers the indication carried in the route to determine that PE1 can forward the BUM traffic to CE1.

S6. The PE receives the traffic sent by the CE, and determines that the traffic is BUM traffic.

For example, CE1 sends broadcast traffic to CE2, and CE2 sends multicast traffic to CE1. After receiving the traffic, PE1 and PE3 determine that the traffic is BUM traffic.

S7. The PE searches the forwarding table, and determines the PE corresponding to the BUM traffic.

After receiving the broadcast traffic sent by CE1, PE1 determines that the BUM traffic needs to be forwarded to PE3 according to its stored forwarding table, encapsulates the broadcast traffic, and forwards it to CE2 through PE3.

After receiving the multicast traffic sent by CE2, PE3 determines that the BUM traffic needs to be forwarded to PE1 as the DF according to its stored forwarding table, encapsulates the multicast traffic and forwards it to CE1 through PE1.

Since the BUM traffic from CE2 to CE1 is no longer copied and forwarded by non-DF PE2, there is no need to replicate multiple copies of this type of BUM traffic in the backbone network. Therefore, it can save bandwidth in the EVPN network and improve traffic forwarding in the EVPN network. s efficiency.

Correspondingly, this application provides a traffic forwarding device, which is applied to the first PE of EVPN, as shown in Figure 4, including:

The receiving unit is configured to receive an Ethernet auto-discovery route sent by PEs in different Ethernet segments, wherein the Ethernet auto-discovery route carries PE forwarding information, and the extended community attribute of the Ethernet auto-discovery route carries a specified identifier, The specified identifier is used to indicate whether the PE forwards BUM traffic;

A recording unit, configured to record the specified identifier of the PE in the forwarding table;

The sending unit is configured to determine the second PE from the forwarding table according to the specified identifier and forward the BUM traffic to the second PE if receiving the BUM traffic of the customer-side edge device CE connected to the first PE.

Optionally, the sending unit is further configured to forward the known unicast traffic according to the forwarding table if receiving the known unicast traffic of the client-side edge device CE connected to the first PE.

Optionally, the specified identifier is located in a reserved field in the extended community attribute of the ESI label of the Ethernet auto-discovery route;

When the specified identifier is set to the first value, it means that the PE corresponding to the specified identifier is a PE that is single-homed by the designated forwarder DF or CE;

When the specified identifier is set to the second value, it indicates that the PE corresponding to the specified identifier is a non-DF for CE multi-homing access.

Correspondingly, this application provides a traffic forwarding device, which is applied to the second PE of EVPN, as shown in Figure 5, including:

The sending unit is configured to send the Ethernet auto-discovery route with the specified identifier in the extended community attribute to PEs in different Ethernet segments, so that the first PE that records the specified identifier forwards the route sent by the CE connected to the first PE according to the specified identifier. BUM traffic.

Optionally, the sending unit is specifically configured to, if it is a PE that is single-homed by DF or CE, send to PEs in different Ethernet segments the extended community attribute that carries the specified identifier and is set as the first value. Automatically discover routes; if it is a non-DF with CE multi-homing access, send the Ethernet auto-discovery routes with the specified identifier set as the second value in the extended community attribute to PEs in different Ethernet segments.

It should be noted that one PE may have functions of the first PE and the second PE respectively, and different functions may be adapted according to different networking environments where the PE is located.

Correspondingly, the present application provides a network device, as shown in FIG. 6 , including a transceiver, a processor, and a machine-readable storage medium, where the machine-readable storage medium stores machine-executable instructions that can be executed by the processor, The processor is caused by the machine-executable instructions to: carry out the method steps of any one of the above.

Correspondingly, the present application provides a machine-readable storage medium, which stores machine-executable instructions, and when called and executed by a processor, the machine-executable instructions prompt the processor to implement any one of the method steps above.

The technical solutions provided by the embodiments of this specification may include the following beneficial effects:

In the embodiment of this specification, the Ethernet auto-discovery routes are exchanged between PEs in multiple Ethernet segments. The Ethernet auto-discovery routes carry forwarding information and designated identifiers, and the designated identifiers can be sent to other Ethernet segments The PE notifies itself whether it can forward BUM traffic to its connected CE, so that PEs in other Ethernet segments can directly forward BUM traffic to the PE that can forward BUM traffic, avoiding bandwidth waste on the EVPN network.

It should be understood that this specification is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof.

The above is only the preferred implementation mode of this specification, and is not intended to limit this specification. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this specification shall be included in this specification. within the scope of protection.

Claims (12)

1. A traffic forwarding method is characterized in that a first network side edge device PE applied to an Ethernet virtual private network EVPN comprises the following steps:

receiving Ethernet automatic discovery routes sent by PEs in different Ethernet segments, wherein the extended group attribute of the Ethernet automatic discovery route carries an appointed identification which is used for indicating whether the PEs forward broadcast, unknown unicast and multicast BUM flow;

recording the designated identification of the PE in a forwarding table;

and if the first PE receives the BUM flow of the connected customer-side edge device CE, determining a second PE from the forwarding table according to the designated identifier, and forwarding the BUM flow to the second PE.

2. The method of claim 1, wherein after recording the PE's assigned identity in a forwarding table, further comprising:

and if the first PE receives the known unicast traffic of the connected customer-side edge device CE, forwarding the known unicast traffic according to the forwarding table.

3. The method according to claim 1 or 2, wherein the specified identity is located in a reserved field in an Ethernet Segment Identity (ESI) tag extended community attribute of the Ethernet auto-discovery route;

when the designated identifier is set to a first value, the PE corresponding to the designated identifier is a PE which is accessed by a designated forwarder DF or CE single attribute;

and when the designated identifier is set to a second value, indicating that the PE corresponding to the designated identifier is a non-DF of the CE multi-homing access.

4. A traffic forwarding method is applied to a second PE of an EVPN, and comprises the following steps:

and sending the Ethernet automatic discovery route carrying the specified identifier in the extended group attribute to PEs in different Ethernet segments, so that the first PE recording the specified identifier forwards the BUM flow sent by the CE connected with the first PE according to the specified identifier.

5. The method of claim 4, wherein sending Ethernet auto-discovery routes to PEs in different Ethernet segments comprises:

if the self is the PE with DF or CE single attribution access, the automatic discovery route of the Ethernet with the appointed identification set as the first value in the extended group attribute is sent to the PE in different Ethernet segments;

and if the self is a non-DF of the CE multi-homing access, sending the Ethernet automatic discovery route carrying the specified identifier set as the second value in the extended group attribute to the PEs in different Ethernet segments.

6. A traffic forwarding apparatus, wherein a first PE applied to an EVPN comprises:

a receiving unit, configured to receive a PE in different ethernet segments and send an ethernet automatic discovery route, where an extended group attribute of the ethernet automatic discovery route carries an assigned identifier, and the assigned identifier is used to indicate whether the PE forwards a BUM traffic;

a recording unit, configured to record the specified identifier of the PE in a forwarding table;

and a sending unit, configured to determine, according to the specified identifier, a second PE from the forwarding table if the BUM traffic of the customer-side edge device CE connected to the first PE is received, and forward the BUM traffic to the second PE.

7. The apparatus of claim 6, wherein the sending unit is further configured to, if known unicast traffic of the customer-side edge device CE connected to the first PE is received, forward the known unicast traffic according to the forwarding table.

8. The apparatus according to claim 6 or 7, wherein the specified identification is located in a reserved field in an ESI tag extended community attribute of the Ethernet auto-discovery route;

when the designated identifier is set to a first value, indicating that the PE corresponding to the designated identifier is a PE to which a designated forwarder DF or CE is singly affiliated and accessed;

and when the designated identifier is set to a second value, indicating that the PE corresponding to the designated identifier is a non-DF of the CE multi-homing access.

9. A traffic forwarding apparatus, wherein a second PE applied to EVPN comprises:

a sending unit, configured to send an ethernet auto discovery route carrying an assigned identifier in an extended group attribute to PEs in different ethernet segments, so that a first PE recording the assigned identifier forwards a BUM traffic sent by a CE connected to the first PE according to the assigned identifier.

10. The apparatus according to claim 9, wherein the sending unit is specifically configured to send, to the PEs in different ethernet segments, an ethernet auto discovery route in which the extended community attribute carries the specified identifier set to the first value if the PE is a DF or CE single-homed PE; and if the self is a non-DF of the CE multi-homing access, sending the Ethernet automatic discovery route carrying the specified identifier set as the second value in the extended community attribute to the PEs in different Ethernet segments.

11. A network device comprising a transceiver, a processor, and a machine-readable storage medium storing machine-executable instructions executable by the processor, the processor being caused by the machine-executable instructions to: carrying out the method steps of any one of claims 1 to 3 or 4 to 5.

12. A machine-readable storage medium having stored thereon machine-executable instructions that, when invoked and executed by a processor, cause the processor to: carrying out the method steps of any one of claims 1 to 3 or 4 to 5.

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