DETAILED ACTION
Notice of AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08/13/2024 is acknowledged.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-6 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim et al. (US 20060159009 A1), hereinafter referenced as Kim.
Regarding claim 1, Kim teaches a router, comprising: a processing system including a processor; and a memory that stores executable instructions that, when executed by the processing system, facilitate performance of operations (Para. [0003]-Kim discloses a fast rerouting apparatus and method of an MPLS multicast packet for rapidly coping with a failure generated when the MPLS multicast packet is transmitted. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP is required. Fig. 1, Para. [0011]-Kim discloses the fast rerouting apparatus comprises: a message sender for sending and receiving a message to and from an upstream or downstream node; a message processor for, when a path requested for routing through a routing request message from the upstream node is a path to perform fast rerouting, sending a routing request message for establishing a next hop database (NHDB) to the downstream node through the message sender, and establishing the NHDB using information included in a response message received from the downstream node; and a storage for storing the established NHDB), the operations comprising:
receiving a point-to-multipoint dataflow comprising a plurality of packets (Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router.");
forwarding, to a data network, packets of the point-to-multipoint dataflow for communication to a plurality of point-to-multipoint receivers along respective Label Switched Paths (Para. [0006]-Kim discloses two Label Switching Routers (LSRs) must agree on the meaning of the labels used to forward traffic between and through them. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router.");
identifying a network failure between the router and a nexthop router for one Label Switched Path (Fig. 14, Para. [[0109]-Kim discloses when R2 detects a failure of the network, R2 notifies R6 that the failure occurs in order to transmit packets to the backup LSP. The failure can be detected through exchange of a Hello message between routers. A Unicast Backup LSP (Label Switched Path) Request object is used, wherein an "F" flag should be set); and
routing packets of the point-to-multipoint dataflow according to a preexisting unicast backup Label Switched Path for the one Label Switched Path (Fig. 14, Para. [[0109]-Kim discloses when R2 detects a failure of the network, R2 notifies R6 that the failure occurs in order to transmit packets to the backup LSP. The failure can be detected through exchange of a Hello message between routers. A Unicast Backup LSP (Label Switched Path) Request object is used, wherein an "F" flag should be set).
Regarding claim 2, Kim teaches the router of claim 1,
Kim further teaches pushing a point-to-multipoint label associated with the nexthop router onto a label stack of a received packet of the point-to-multipoint dataflow to forward the received packet of the point-to-multipoint dataflow (Fig. 5, Para. [0055-0057]-Kim discloses R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router); and
responsive to the identifying the network failure, pushing a backup label associated with the preexisting unicast backup Label Switched Path onto the label stack of the received packet (Fig. 1, Para. [0039]-Kim discloses when a failure occurs between R2 and R3, R2 sends a packet, which is to be sent through R3, to R6 in order to send it through the backup LSP. At this time, R2 allocates an Inbound label allocated by R4 of the protected LSP and pushes a label for the backup LSP. Fig. 11, Para. [0027]-Kim discloses format of a Unicast Backup LSP Request object of a signaling protocol according to the present invention).
Regarding claim 3, Kim teaches the router of claim 2,
Kim further teaches responsive to the identifying the network failure, pushing a backup label associated with the preexisting unicast backup Label Switched Path onto a label stack of the received packet (Figs. 2-3 and 5, Para. [0055-0057]-Kim discloses transmission of a packet on a network to which the MPLS fast rerouting ... R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets ... this fast rerouting applied to MPLS unicast is applied to MPLS multicast),
the preexisting unicast backup Label Switched Path forming a protection path to the nexthop router for use during the network failure (Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6); and
forwarding the received packet according to the backup label (Para. [0006]-Kim discloses two Label Switching Routers (LSRs) must agree on the meaning of the labels used to forward traffic between and through them. Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6).
Regarding claim 4, Kim teaches the router of claim 3,
Kim further teaches the pushing the backup label onto the label stack of the received packet comprises: pushing a backup label operative to forward the received packet to the nexthop router over the protection path to the nexthop router (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6),
the nexthop router is responsive to receiving the packets of the point-to-multipoint dataflow, including the received packet, for communication to designated point-to-multipoint receivers along the respective Label Switched Paths (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router).
Regarding claim 5, Kim teaches the router of claim 4,
Kim further teaches the pushing the backup label onto the label stack of the received packet comprises: pushing a backup label operative to forward the received packet to the nexthop router over the protection path to the nexthop router (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6),
the nexthop router is responsive to receiving the packets of the point-to-multipoint dataflow to pop the backup label from a label stack of the packets of the point-to-multipoint dataflow and to forward the packets of the point-to-multipoint dataflow according to a point-to-multipoint label associated with the designated point-to-multipoint receivers along the respective Label Switched Paths (Fig. 5, Para. [0056]-Kim discloses R6 swaps label 17 for label 22 to transmit the packet to the next node in the protected LSP, router R7. If penultimate-hop-popping is used, R7 transmits a packet, that is received from R6, to the merge point, R4, after it pops the label 22 from the packet ... If penultimate-hop-popping is not used, R4 will pop the bypass tunnel's label and examine the label underneath to determine the path that the packet is to follow. Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6).
Regarding claim 6, Kim teaches the router of claim 3,
Kim further teaches receiving additional packets of the of the point-to-multipoint dataflow (Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router."); and
forwarding the additional packets according to the backup label until the data network has reconverged following the network failure (Para. [0007-0008]-Kim discloses a failure that occurs on a network is restored by establishing a new LSP to replace the LSP where the failure occurs at the router and then transmitting a packet to be transmitted through the LSP where the failure occurs through the newly established LSP ... The fast rerouting sets up the backup LSP before any failure occurs, and when the failure occurs on a network, redirects a packet to the closest location from a location where the failure occurs. Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 20060159009 A1), hereinafter referenced as Kim, in view of Atlas et al. (US 8958286 B1), hereinafter referenced as Atlas, and further in view of Liam Casey (US 20030142674 A1), hereinafter referenced as Casey.
Regarding claim 7, Kim teaches the router of claim 1,
Kim further teaches receiving subsequent packets of the point-to-multipoint dataflow (Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Kim fails to teach determining that the data network has reconverged following the network failure; receiving new unicast primary routes based on a reconvergence of the data network.
However, Atlas teaches determining that the data network has reconverged following the network failure (Col. 18, Lines [43-44]-Atlas discloses source node 12B determines that the network has converged (e.g., based on signaling or a time-out));
receiving new unicast primary routes based on a reconvergence of the data network (Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure).
Kim and Atlas are both considered to be analogous to the claimed invention because they are in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on network reconvergence and unicast routes, with a motivation for receiving unicast routes upon reconvergence, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Kim fails to teach adding a unicast transport label to a packet label stack of the subsequent packets, wherein the unicast transport label is associated with the nexthop router.
However, Casey teaches adding a unicast transport label to a packet label stack of the subsequent packets (Para. [0077]-Casey discloses if it is a unicast packet ... then use the SET label to index into the SET to Core (S2C) Label Mapping to retrieve the new label stack and outgoing core i/f. Swap service labels, add transport label and forward over the outgoing i/f currently associated with the transport LSP);
the unicast transport label is associated with the nexthop router (Figs. 3-6, Para. [0077]-Casey discloses if it is a unicast packet (SET dest. MAC address is that of Core-PE and the SET label has a valid value in the low order bits) then use the SET label to index into the SET to Core (S2C) Label Mapping to retrieve the new label stack and outgoing core i/f. Swap service labels, add transport label and forward over the outgoing i/f currently associated with the transport LSP).
Casey is considered to be analogous because it is in the same field of communication networks, dealing with multi-protocol label switching label control.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim in view of Atlas to incorporate the teachings of Casey on unicast transport label (UTL), with a motivation to add UTL to a packet label stack, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 8, Kim in view of Atlas and Casey teaches the router of claim 7,
Kim further teaches subsequently, forwarding received packets to the point-to-multipoint receivers according to the update (Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Kim fails to teach receiving an update to a multicast Label Distribution Protocol tree for routing the plurality of packets in the data network, the update based the reconvergence of the data network.
However, Atlas teaches receiving an update to a multicast Label Distribution Protocol tree for routing the plurality of packets in the data network (Col. 12, Lines [36-41 and 58-66]-Atlas discloses routing component 104 periodically updates RIB 110 to accurately reflect the topology of the network and other entities. RIB 110 may describe a topology of the computer network in which network device 100 resides, and may also include routes through the shared trees in the computer network ... routing protocols 116 include ..., and Label Distribution Protocol (LDP) 116D, for exchanging routing information with other routing devices and for updating RIB {Routing Information Base} 110. In addition, routing protocols 116 include Multicast Label Distribution Protocol (mLDP) 116E and Protocol Independent Multicast (PIM) 116N for routing traffic through a computer network with other routing devices conceptually formed into shared multicast trees. Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure);
the update based the reconvergence of the data network (Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure. Col. 18, Lines [38-47]-Atlas discloses after calculation of the primary and alternate next-hops is completed (176), source node 12B will handle other messages received from neighbor devices (178), e.g., routing updates. Source node 12B begins forwarding subsequently received packets using the new primary next-hop (180). Once source node 12B determines that the network has converged (e.g., based on signaling or a time-out), and so it can reasonably be assumed that the network traffic is no longer being carried on the MRT, then source node 12B installs the new MRT next-hops).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim in view of Casey to incorporate the teachings of Atlas on multicast Label Distribution Protocol (mLDP) tree, with a motivation to update mLDP, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Claims 9-16 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 20060159009 A1), hereinafter referenced as Kim, in view of Atlas et al. (US 8958286 B1), hereinafter referenced as Atlas.
Regarding claim 9, Kim teaches the router of claim 1,
Kim further teaches identifying the preexisting unicast backup Label Switched Path for the one Label Switched Path (Para. [0091]-Kim discloses setting up an existing unicast LSP is performed at each router. When requested to set up the unicast backup LSP, R6 selects ERs (Explicit Routes) to set up the unicast backup LSP with reference to the NHDB. Para. [0079]-Kim discloses Unicast Backup LSP Request object is used when another router of a multicast tree is requested to set a unicast LSP. Here, the multicast tree refers to paths used to transmit a multicast packet to hosts belonging to the multicast group).
Kim fails to teach the preexisting unicast backup Label Switched Path is associated with a directly-connected neighbor router that provides a loop free path with respect to the nexthop router.
However, Atlas teaches the preexisting unicast backup Label Switched Path is associated with a directly-connected neighbor router that provides a loop free path with respect to the nexthop router (Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on unicast backup Label Switched Path, with a motivation to provide loop-free path, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 10, Kim teaches the router of claim 1,
Kim fails to teach identifying a remote loop free alternate backup path; and routing packets of the point-to-multipoint dataflow according to the remote loop free alternate backup path.
However, Atlas teaches identifying a remote loop free alternate backup path (Col. 17, Lines [4-5]-Atlas discloses remote destinations may not be advertising additional IP loopback addresses for the MRTs. Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates); and
routing packets of the point-to-multipoint dataflow according to the remote loop free alternate backup path (Col. 17, Lines [4-13]-Atlas discloses remote destinations may not be advertising additional IP loopback addresses for the MRTs. In that case, a router attached to a proxy-node, which represents destinations outside the local island, must advertise IP addresses associated with that proxy-node. Packets sent to an address associated with a proxy-node will have their outer IP header removed by the router attached to the proxy-node and be forwarded by the router along the outgoing interface on the MRT towards a router outside the local island that was represented by the proxy-node. Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on loop-free alternate backup path, with a motivation to route packets of the point-to-multipoint dataflow, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 11, Kim teaches a non-transitory machine-readable medium, comprising executable instructions that, when executed by a processing system including a processor, facilitate performance of operations (Para. [0003]-Kim discloses a fast rerouting apparatus and method of an MPLS multicast packet for rapidly coping with a failure generated when the MPLS multicast packet is transmitted. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP is required. Fig. 1, Para. [0011]-Kim discloses the fast rerouting apparatus comprises: a message sender for sending and receiving a message to and from an upstream or downstream node; a message processor for, when a path requested for routing through a routing request message from the upstream node is a path to perform fast rerouting, sending a routing request message for establishing a next hop database (NHDB) to the downstream node through the message sender, and establishing the NHDB using information included in a response message received from the downstream node; and a storage for storing the established NHDB), the operations comprising:
receiving, at a router forming an ingress router in a point-to-multipoint network, a point-to-multipoint dataflow comprising a plurality of packets (Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router.");
forwarding, to a data network, packets of the point-to-multipoint dataflow for communication to a plurality of point-to-multipoint receivers along respective Label Switched Paths (Para. [0006]-Kim discloses two Label Switching Routers (LSRs) must agree on the meaning of the labels used to forward traffic between and through them. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router."),
identifying a network failure between the router and a nexthop router for one Label Switched Path (Fig. 14, Para. [[0109]-Kim discloses when R2 detects a failure of the network, R2 notifies R6 that the failure occurs in order to transmit packets to the backup LSP. The failure can be detected through exchange of a Hello message between routers. A Unicast Backup LSP (Label Switched Path) Request object is used, wherein an "F" flag should be set); and
routing packets of the point-to-multipoint dataflow according to a preexisting unicast backup Label Switched Path for the one Label Switched Path (Fig. 14, Para. [[0109]-Kim discloses when R2 detects a failure of the network, R2 notifies R6 that the failure occurs in order to transmit packets to the backup LSP. The failure can be detected through exchange of a Hello message between routers. A Unicast Backup LSP (Label Switched Path) Request object is used, wherein an "F" flag should be set).
Kim fails to explicitly teach the plurality of point-to-multipoint receivers associated with one or more egress nodes of the point-to-multipoint network.
However, Atlas teaches the plurality of point-to-multipoint receivers associated with one or more egress nodes of the point-to-multipoint network (Fig. 5, Col. 34, Lines [2-6]-Atlas discloses multiple P2MP {Point-to-Multipoint} Child Data Objects could be included in a P2MP Label Mapping. In some examples, only those specified in the most recently received P2MP Label Mapping should be stored and used by mLDP 116E of network device 100. Col. 15, Lines [27-34]-Atlas discloses for IP unicast traffic, tunneling may be used. The tunnel egress could be the original destination in the area, the next-next-hop, etc. If the tunnel egress is the original destination router, then the traffic remains on the redundant tree with sub-optimal routing. If the tunnel egress is the next-next-hop, then protection of multi-homed prefixes and node-failure for ABRs is not available. Selection of the tunnel egress is a router-local decision. Col. 36, Lines [29-33]-Atlas discloses if the multicast traffic is PIM, then nodes 432, 434 may mark packets so that the packets self-identify the P2MP tree to which the traffic belongs, i.e., identify which blue/red MRT P2MP tree the packets are part of).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on egress nodes, with a motivation for egress-node-based point-to-multipoint receivers, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 12, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 11,
Kim further teaches pushing a point-to-multipoint label associated with the nexthop router onto a label stack of a received packet of the point-to-multipoint dataflow to forward the received packet of the point-to-multipoint dataflow (Fig. 5, Para. [0055-0057]-Kim discloses R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router); and
responsive to the identifying the network failure, pushing a backup label associated with the preexisting unicast backup Label Switched Path onto the label stack of the received packet (Fig. 1, Para. [0039]-Kim discloses when a failure occurs between R2 and R3, R2 sends a packet, which is to be sent through R3, to R6 in order to send it through the backup LSP. At this time, R2 allocates an Inbound label allocated by R4 of the protected LSP and pushes a label for the backup LSP. Fig. 11, Para. [0027]-Kim discloses format of a Unicast Backup LSP Request object of a signaling protocol according to the present invention).
Regarding claim 13, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 12,
Kim further teaches responsive to the identifying the network failure, pushing a backup label associated with the preexisting unicast backup Label Switched Path onto a label stack of the received packet (Figs. 2-3 and 5, Para. [0055-0057]-Kim discloses transmission of a packet on a network to which the MPLS fast rerouting ... R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets ... this fast rerouting applied to MPLS unicast is applied to MPLS multicast),
the preexisting unicast backup Label Switched Path forming a protection path to the nexthop router for use during the network failure (Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6); and
forwarding the received packet according to the backup label (Para. [0006]-Kim discloses two Label Switching Routers (LSRs) must agree on the meaning of the labels used to forward traffic between and through them. Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6).
Regarding claim 14, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 13,
Kim further teaches the pushing the backup label onto the label stack of the received packet comprises: pushing a backup label operative to forward the received packet to the nexthop router over the protection path to the nexthop router (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6),
the nexthop router is responsive to receiving the packets of the point-to-multipoint dataflow, including the received packet, for communication to designated point-to-multipoint receivers along the respective Label Switched Paths (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6. Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router).
Regarding claim 15, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 14,
Kim further teaches the pushing the backup label onto the label stack of the received packet comprises: pushing a backup label operative to forward the received packet to the nexthop router over the protection path to the nexthop router (Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6),
the nexthop router responsive to receiving the packets of the point-to-multipoint dataflow to pop the backup label from a label stack of the packets of the point-to-multipoint dataflow and to forward the packets of the point-to-multipoint dataflow according to a point-to-multipoint label associated with the designated point-to-multipoint receivers along the respective Label Switched Paths (Fig. 5, Para. [0056]-Kim discloses R6 swaps label 17 for label 22 to transmit the packet to the next node in the protected LSP, router R7. If penultimate-hop-popping is used, R7 transmits a packet, that is received from R6, to the merge point, R4, after it pops the label 22 from the packet ... If penultimate-hop-popping is not used, R4 will pop the bypass tunnel's label and examine the label underneath to determine the path that the packet is to follow. Fig. 13, Para. [0103]-Kim discloses R2 transmits a Path message to R6 based on the selected ER. The Path message transmitted from R2 to R6 includes the same information as the Path message of the protected LSP which is transmitted from R2 to R3, and a Unicast Backup LSP Request object. When R2 receives the Resv message from R6, R2 transmits the Path message for setup of the backup LSP to R6).
Regarding claim 16, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 13,
Kim further teaches receiving additional packets of the of the point-to-multipoint dataflow (Para. [0009]-Kim discloses a new fast rerouting apparatus and method for the MPLS multicast employing a point-to-multipoint LSP. Fig. 10, Para. [0076]-Kim discloses to notify information of a downstream router participating in establishing a point-to-multipoint LSP for an upstream router. Para. [0053]-Kim discloses packets are transmitted on the network using the labels ..., the label is transmitted along R4.fwdarw.R3.fwdarw.R2, or R4.fwdarw.R7.fwdarw.R6.fwdarw.R2. Fig. 1, Para. [0038]-Kim discloses a router sending a packet to the reference router is called "upstream router," and router receiving a packet from the reference router is called "downstream router."); and
forwarding the additional packets according to the backup label until the data network has reconverged following the network failure (Para. [0007-0008]-Kim discloses a failure that occurs on a network is restored by establishing a new LSP to replace the LSP where the failure occurs at the router and then transmitting a packet to be transmitted through the LSP where the failure occurs through the newly established LSP ... The fast rerouting sets up the backup LSP before any failure occurs, and when the failure occurs on a network, redirects a packet to the closest location from a location where the failure occurs. Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Regarding claim 19, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 11,
Kim further teaches identifying the preexisting unicast backup Label Switched Path for the one Label Switched Path (Para. [0091]-Kim discloses setting up an existing unicast LSP is performed at each router. When requested to set up the unicast backup LSP, R6 selects ERs (Explicit Routes) to set up the unicast backup LSP with reference to the NHDB. Para. [0079]-Kim discloses Unicast Backup LSP Request object is used when another router of a multicast tree is requested to set a unicast LSP. Here, the multicast tree refers to paths used to transmit a multicast packet to hosts belonging to the multicast group).
Kim fails to teach the preexisting unicast backup Label Switched Path is associated with a directly-connected neighbor router that provides a loop free path with respect to the nexthop router.
However, Atlas teaches the preexisting unicast backup Label Switched Path is associated with a directly-connected neighbor router that provides a loop free path with respect to the nexthop router (Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on unicast backup Label Switched Path, with a motivation to provide loop-free path, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 20, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 11,
Kim fails to teach identifying a remote loop free alternate backup path; and routing packets of the point-to-multipoint dataflow according to the remote loop free alternate backup path.
However, Atlas teaches identifying a remote loop free alternate backup path (Col. 17, Lines [4-5]-Atlas discloses remote destinations may not be advertising additional IP loopback addresses for the MRTs. Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates); and
routing packets of the point-to-multipoint dataflow according to the remote loop free alternate backup path (Col. 17, Lines [4-13]-Atlas discloses remote destinations may not be advertising additional IP loopback addresses for the MRTs. In that case, a router attached to a proxy-node, which represents destinations outside the local island, must advertise IP addresses associated with that proxy-node. Packets sent to an address associated with a proxy-node will have their outer IP header removed by the router attached to the proxy-node and be forwarded by the router along the outgoing interface on the MRT towards a router outside the local island that was represented by the proxy-node. Col. 32, Lines [4-8]-Atlas discloses each router along the path, including the originating router, determines which of an LFA {Loop Free Alternative}, the Blue MRT or the Red MRT to use for its next-hops. When a router receives a backup join and is not the destination PLR, the router identifies a unicast alternate to the PLR that avoids the failure-candidate node, creates local multicast group state, and forwards the backup join to that alternate's next-hop. Col. 13, Lines [46-65]-Atlas discloses LFA module 122 may compute and select loop-free alternate (LFA) next-hops ... With LFA, there is no need to tunnel unicast traffic, whether IP or LDP. Col. 15, Lines [7-10]-Atlas discloses with LDP unicast forwarding, regardless of whether topology-identification label or encoding topology in label is used, no additional loopbacks per router are required as are required in the IP unicast forwarding case. Col. 15, Lines [37-38]-Atlas discloses a network device 100 may tunnel IP packets via an LDP LSP. Col. 32, Lines [27-28]-Atlas discloses the backup tree may be the merged set of unicast alternates).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on loop-free alternate backup path, with a motivation to route packets of the point-to-multipoint dataflow, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Claims 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 20060159009 A1), hereinafter referenced as Kim, in view of Atlas et al. (US 8958286 B1), hereinafter referenced as Atlas, and further in view of Liam Casey (US 20030142674 A1), hereinafter referenced as Casey.
Regarding claim 17, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 11,
Kim further teaches receiving subsequent packets of the point-to-multipoint dataflow (Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Kim fails to teach determining that the data network has reconverged following the network failure; receiving new unicast primary routes based on a reconvergence of the data network.
However, Atlas teaches determining that the data network has reconverged following the network failure (Col. 18, Lines [43-44]-Atlas discloses source node 12B determines that the network has converged (e.g., based on signaling or a time-out));
receiving new unicast primary routes based on a reconvergence of the data network (Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure).
Kim and Atlas are both considered to be analogous to the claimed invention because they are in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim to incorporate the teachings of Atlas on network reconvergence and unicast routes, with a motivation for receiving unicast routes upon reconvergence, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Kim fails to teach adding a unicast transport label to a packet label stack of the subsequent packets, wherein the unicast transport label is associated with the nexthop router.
However, Casey teaches adding a unicast transport label to a packet label stack of the subsequent packets (Para. [0077]-Casey discloses if it is a unicast packet ... then use the SET label to index into the SET to Core (S2C) Label Mapping to retrieve the new label stack and outgoing core i/f. Swap service labels, add transport label and forward over the outgoing i/f currently associated with the transport LSP);
the unicast transport label is associated with the nexthop router (Figs. 3-6, Para. [0077]-Casey discloses if it is a unicast packet (SET dest. MAC address is that of Core-PE and the SET label has a valid value in the low order bits) then use the SET label to index into the SET to Core (S2C) Label Mapping to retrieve the new label stack and outgoing core i/f. Swap service labels, add transport label and forward over the outgoing i/f currently associated with the transport LSP).
Casey is considered to be analogous because it is in the same field of communication networks, dealing with multi-protocol label switching label control.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim in view of Atlas to incorporate the teachings of Casey on unicast transport label (UTL), with a motivation to add UTL to a packet label stack, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Regarding claim 18, Kim in view of Atlas teaches the non-transitory machine-readable medium of claim 17,
Kim further teaches subsequently, forwarding received packets to the point-to-multipoint receivers according to the update (Fig. 5, Para. [0056]-Kim discloses a process where R2 transmits a packet through a backup LSP, particularly when a failure occurs at a link between R2 and R3. R2 transmits a packet to R4 rather than R3 through a backup LSP (a.k.a., a bypass tunnel). When a failure does not occur, R2 will switch traffic received from R1 and transmit a packet, which is received from R1 into a label 12, and then R3 transmits the packet to R4 after it changes the label 12 of the packet into a label 14. In contrast, when a failure occurs, R2 transmits the packet, which is received from R1, to R6 after it changes a label 37 of the packet into a label 14 and pushes label 17. That is, the label 37 will be swapped for one which will be understood by R4 to indicate the protected LSP, and the bypass tunnel's label will then be pushed onto a label-stack of the redirected packets).
Kim fails to teach receiving an update to a multicast Label Distribution Protocol tree for routing the plurality of packets in the data network, the update based the reconvergence of the data network.
However, Atlas teaches receiving an update to a multicast Label Distribution Protocol tree for routing the plurality of packets in the data network (Col. 12, Lines [36-41 and 58-66]-Atlas discloses routing component 104 periodically updates RIB 110 to accurately reflect the topology of the network and other entities. RIB 110 may describe a topology of the computer network in which network device 100 resides, and may also include routes through the shared trees in the computer network ... routing protocols 116 include ..., and Label Distribution Protocol (LDP) 116D, for exchanging routing information with other routing devices and for updating RIB {Routing Information Base} 110. In addition, routing protocols 116 include Multicast Label Distribution Protocol (mLDP) 116E and Protocol Independent Multicast (PIM) 116N for routing traffic through a computer network with other routing devices conceptually formed into shared multicast trees. Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure);
the update based the reconvergence of the data network (Col. 35-36, Lines [64-67 and 1-5]-Atlas discloses to converge, first all routers in the area update the broken MRT color for each multicast source (or unicast destination). Then, once all routers in the area are known to have updated the broken MRT color, whether that is determined by a timer, signaling or some other mechanism, all of the routers update the unbroken MRT color. Once all routers in the area have also updated their unbroken MRT color, the multicast trees are using the new MRTs and are prepared for another single failure. Col. 18, Lines [38-47]-Atlas discloses after calculation of the primary and alternate next-hops is completed (176), source node 12B will handle other messages received from neighbor devices (178), e.g., routing updates. Source node 12B begins forwarding subsequently received packets using the new primary next-hop (180). Once source node 12B determines that the network has converged (e.g., based on signaling or a time-out), and so it can reasonably be assumed that the network traffic is no longer being carried on the MRT, then source node 12B installs the new MRT next-hops).
Atlas is considered to be analogous because it is in the same field of computer networks, dealing with forwarding network traffic within computer networks.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified the Kim in view of Casey to incorporate the teachings of Atlas on multicast Label Distribution Protocol (mLDP) tree, with a motivation to update mLDP, and guarantee restoring a failure occurring on a multiprotocol label switching (MPLS) network, (Kim, Para. [0003).
Conclusion
Listed below are the prior arts made of record and not relied upon but are considered pertinent to applicant`s disclosure.
Eckert et al. (US 20160254991 A1)-discloses Para. [0028-0029]-Eckert discloses routing of multicast packets ... The reservation process must be done again if the explicit path is altered in response to a change in network topology or conditions. The RSVP-TE process can be extended to multicast trees using point-to-multipoint (P2MP) RSVP-TE. Each multicast group will have its own tree reservation process and its own set of labels, requiring significant state at each node for forwarding tables relating labels to group and source information …. …Fig. 1-2
SHAIKH et al. (US 20180314612 A1)-discloses Para. [0020]-Shaikh discloses determination can be made as to the time for the network to re-converge following failures …. …Fig. 1-2
Lin et al. (US 20210211372 A1)-discloses [0053] Referring next to the example method 350, the protected egress PE may perform different branches of the example method 350 responsive to the occurrence of different events. (Event Branch Point 355) For example, responsive to receiving an advertisement including the first (KU) label and the second (MPP) label, the example method 350 may establish, by the protected egress PE, forwarding state for the backup path for fast reroute, including (1) the second (MPP) label from the advertisement, (2) the first (KU) label from the advertisement, and (3) a transport label or label stack associated with a backup transport tunnel to the protector egress PE. (Block 360) This forwarding information may be used in the event of an unavailable link when known unicast data to be forwarded to the multihomed CE is received .… …Fig. 1-2
Carofiglio et al. (US 20170034041 A1)-discloses Fig. 4D, Para. [0052]-Carofiglio discloses IU 406 may be sent as a unicast update from the new location to the prior location. This allows faster mobility with less disruption on the network. Fig. 6D, Para. [0060]-Carofiglio discloses the network may re-converge to a new, shortest path tree rooted at device H that is not necessarily congruent with the previous tree. Para. [0025]-Carofiglio discloses mechanism that supports multipoint-to-point (MP2P) traffic from devices inside the LLN towards a central control point (e.g., LLN Border Routers (LBRs) or “root nodes/devices” generally), as well as point-to-multipoint (P2MP) traffic from the central control point to the devices inside the LLN …. …Fig. 1-4
Chen et al. (US 20090219806 A1)-discloses method for protecting the head node of a Point to Multipoint Label Switched Path (P2MP LSP) includes: a Backup Head Node (BHN) establishes a backup LSP from the BHN to all Merge Points (MPs), where the backup LSP bypasses a Master Head Node (MHN); the MHN forwards data along an LSP already established between the MHN and the MPs; when a head node switchover condition is met, the BHN is switched to a master mode to forward data along the backup LSP established between the BHN and the MPs. A system and apparatus for protecting the head node are also provided. With the head node protection solution provided by the present disclosure, the head node is well protected and the protection mechanisms for the P2MP LSP are therefore more complete. This can further promote the scale deployment of P2MP systems…. …Fig. 1-4
Any inquiry concerning this communication or earlier communications from the examiner should be directed to OLADIRAN GIDEON OLALEYE whose telephone number is (571)272-5377. The examiner can normally be reached Monday - Friday: 07:30am - 05:30pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s SPE, NICHOLAS A. JENSEN can be reached on (571) 270-5443. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/OLADIRAN GIDEON OLALEYE/Examiner, Art Unit 2472
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