DETAILED ACTION
Notice of Pre-AIA or 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 .
Claim Rejections - 35 USC § 102
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 (i.e., changing from AIA to pre-AIA ) 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 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.
Claim(s) 1, 9, 11 and 19 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Koskiahde, et al. (US Pre Grant Publication No. 2015/0295635 A1)
Regarding claim 1, Koskiahde discloses a method comprising,
receiving a first frame at a network device from a redundancy device and including a first sequence number, wherein the network device is connected to the redundancy device via a first link and a second link for transmitting duplicate frames and storing the first sequence number based on the first frame corresponding to an expected order of frames; (Koskiahde discloses that a Redbox/DANP/apparatus [fig. 1a, element 109 paragraph 0039; note also fig. 2b and paragraph 0047 – device with two redundant ports and an interlink port for forwarding] maintains/stores a “newest sequence number” which is the highest sequence number received in a redundant/duplicate transmission to the first and second network interface/redundant ports connected a first and second path/LANs A and B [fig. 2b, 222/224; note also fig 1a, element 109, connections to LAN A and B]. Therefore, there is a first frame received on the first path with a first [most current/highest/expected order] sequence number that sets the “Accept Window” as all sequence numbers in window that are higher than the stored sequence number of the first frame [paragraphs 0057-0063, 0067-0071, 0047-0050 in particular 0063] the first frame also establishes the selective accept window as all sequence numbers less than the sequence number of the first frame [paragraphs 0063, 0049, 0050]. The first frame is in the “accept window” [i.e. highest seen sequence number] and is immediately forwarded on the interlink port [paragraphs 0047, 0071]. After receiving the first frame, a second frame may be received from either the first or second interface [i.e. it may be received from the second interface] with a sequence number less than the first frame but within the “selective accept” window, which is an out of order frame, and which is paused and further analyzed to see if it qualifies for forwarding [paragraph 0070].)
receiving a second frame at the network device from the redundancy device including a second sequence number; determining that the second frame does not correspond to the expected order of frames based on the second sequence number and the first sequence number; and pausing transmission of frames to a destination network device in response to determining the second frame does not correspond to the expected order of frames (As discussed in (a), supra after a first frame received in the “Accept Window” received via a first port, a second frame in the “Selective Accept Window” may be received via a second/redundant path/interface that is out of order, having a lower sequence number than the first frame [paragraph 0067 - Having an accept window and a selective accept window provides reception of frames out of order from different redundant paths.”; see also paragraphs 0057-0063, 0067-0071, 0047-0050]. Based on the second frame being in the “Selective Accept Window” [i.e. it is an out of order frame/frame that does not conform to the expected order of frames], which is determined based on the upper limit set by the first frame’s sequence number and the sequence number of the second frame falling within the window, the forwarding/relaying of the second frame is paused while the sequence number of the second frame is further analyzed to see if the frame has been previously transmitted [paragraph 0070, 0067, 0047].)
Regarding claim 9, Koskiahde discloses after receiving the second frame, receiving a third frame from the redundancy device, wherein the third frame is sequential with respect to the first frame, wherein the first frame is received on the first link and the third frame is received on the second link. (Koskiahde discloses that a frame with a new highest sequence number may be received with the frames being sent in incremental order [paragraph 0059 – incremental higher number].)
Regarding claim 11, Koskiahde discloses a network device for detecting out-of-order frames (paragraph 0067 – selective accept window is for out of order packets with number less than accept window/next expected sequence number), comprising
at least one memory (paragraph 0101)
a first network interface configured to receive first frames from a first path (fig. 1a, element 109, connection to lan A)
a second network interface configured to receive second frames from a second path (fig. 1a, element 109, connection to lan B)
A link redundancy entity configured to receive a first frame at a network device from a redundancy device (fig. 1a, element 109, connection to lan A connects to redundancy device/DANP 108) and including a first sequence number wherein the network device is connected to the redundancy device via a first link and a second link for transmitting duplicate frames, store the first sequence number based on the first frame corresponding to an expected order of frames (Koskiahde discloses that a Redbox/DANP/apparatus [fig. 1a, element 109 paragraph 0039; note also fig. 2b and paragraph 0047 – device with two redundant ports and an interlink port for forwarding] maintains a “newest sequence number” which is the highest sequence number received in a redundant/duplicate transmission to the first and second network interface/redundant ports connected a first and second path/LANs A and B [fig. 2b, 222/224; note also fig 1a, element 109, connections to LAN A and B]. Therefore, there is a first frame received on the first path with a first [most current/highest] sequence number that sets the “Accept Window” as all sequence numbers in window that are higher than the sequence number of the first frame [paragraphs 0057-0063, 0067-0071, 0047-0050 in particular 0063] the first frame also establishes the selective accept window as all sequence numbers less than the sequence number of the first frame [paragraphs 0063, 0049, 0050]. The first frame is in the “accept window” [i.e. highest seen sequence number] and is immediately forwarded on the interlink port [paragraphs 0047, 0071]. After receiving the first frame, a second frame may be received from either the first or second interface [i.e. it may be received from the second interface] with a sequence number less than the first frame but within the “selective accept” window, which is an out of order frame, and which is paused and further analyzed to see if it qualifies for forwarding [paragraph 0070].)
receive a second frame at the network device from the redundancy device including a second sequence number, determine that the second frame does not correspond to the expected order of frames based on the second sequence number and the first sequence number and pause transmission of frames to a destination network device in response to determining the second frame does not correspond to the expected order of frames. (As discussed in (d), supra after a first frame received in the “Accept Window” received via a first port, a second frame in the “Selective Accept Window” may be received via a second/redundant path/interface that is out of order, having a lower sequence number than the first frame [paragraph 0067 - Having an accept window and a selective accept window provides reception of frames out of order from different redundant paths.”; see also paragraphs 0057-0063, 0067-0071, 0047-0050]. Based on the second frame being in the “Selective Accept Window” [i.e. it is an out of order frame/frame that does not conform to the expected order of frames], which is determined based on the upper limit set by the first frame’s sequence number and the sequence number of the second frame falling within the window, the forwarding/relaying of the second frame is paused while the sequence number of the second frame is further analyzed to see if the frame has been previously transmitted [paragraph 0070, 0067, 0047].)
Regarding claim 19, Koskiahde discloses after receiving the second frame, receiving a third frame from the redundancy device, wherein the third frame is sequential with respect to the first frame, wherein the first frame is received on the first link and the third frame is received on the second link. (Koskiahde discloses that a frame with a new highest sequence number may be received with the frames being sent in incremental order [paragraph 0059 – incremental higher number].)
Allowable Subject Matter
Claims 2-8, 10, 12-18 and 20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claims 2 and 12, the prior art fails to teach, suggest or disclose generating a notification for an application layer identifying a frame sequence ordering issue that could not be recovered. That is, the primary reference of Koskiahde is silent as to detecting unrecoverable frame sequence ordering issues, let alone reporting such issues to the application layer. Furthermore, no other art teaching this limitation could be located. Therefore, the prior art fails to teach suggest or disclose all elements of the claimed invention.
Regarding claims 3 and 13, the prior art fails to teach, suggest or disclose in response to determining the second frame does not correspond to the expected order of frames, storing the second frame in a buffer and starting a timer. That is, looking to claim 1, it is interpreted that the holding of the frame in a buffer while determining if it has already been forwarded corresponds to the pausing of transmission. It is noted that this interpretation, although within the broadest reasonable interpretation of the claims, it not consistent with Applicant’s intent, as applicant teaches that the pausing of transmission is more substantial and is to allow the sequence numbers on the link that are behind to “catch up” to the sequence numbers on the other link so that the two links do not become so out of synchronization that a sequence number overrun occurs where the same sequence number on each link represents a different frame because of looping of the sequence number. Therefore, although the second frame in Koskiahde is stored in a buffer, no timer is started as a timer is not needed to identify how long it can be waited until the sequence numbers may overrun as is carried out in the present application. It was thought that perhaps the aging information could be used for this (see Koskiahde, paragraphs 0055, 0074). However, the aging information of Koskiahde is only updated in response to receiving a “new” sequence number that is higher than the highest presently received sequence number and is therefore not updated in response to the second frame, which is an older number within the conditional acceptance window (paragraphs 0055, 0074}. Therefore, the prior art fails to teach, suggest or disclose all elements of the claimed invention.
Regarding claims 4-8 and 14-18, the claims depend, directly or indirectly, from claims 3 and 13 and are allowable for at least the reasons stated with respect to those claims, supra.
Regarding claims 10 and 20, the prior art fails to teach, suggest or disclose after receiving the second frame, receiving a third frame from the redundancy device, wherein the third frame is sequential with respect to the first frame, wherein the first frame is received on the first link and the third frame is received on the second link. That is, as was discussed with respect to claims 2 and 12, supra, the system of Koskiahde discloses that the second frame is only held briefly to allow for a determination of if it has already been transmitted. This behavior is inconsistent with holding it until a third frame is received. In fact, modifying Koskiahde to operate in this manner would completely change its methods of operation and therefore would be non-obvious. Furthermore, no other art teaching this limitation could be located. Therefore, the prior art fails to teach, suggest or disclose all elements of the claimed invention.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Kaattari, et al. (US Pre Grant Publication No. 2019/0305900) – disclosing a dual link sequence numbering system similar to Koskiahde
Rangne, et al. (US Pre Grant Publication No. 2014/0347981 A1) – disclosing a dual link sequence numbering system with out of order detection
Kirmann, et al. (EPO Publication No. 1657888) – disclosing a dual link sequence numbering system
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHRISTOPHER M CRUTCHFIELD whose telephone number is (571)270-3989. The examiner can normally be reached 9am-5pm M-F.
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/CHRISTOPHER M CRUTCHFIELD/Primary Examiner, Art Unit 2466
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