Method of Operating a Bidirectional Optical Transmission Link and Corresponding Optical Transmission Link

    公开(公告)号:US20230136924A1

    公开(公告)日:2023-05-04

    申请号:US17980005

    申请日:2022-11-03

    Abstract: The invention relates to a method and apparatus of operating a bidirectional optical transmission link. The optical transmission link includes a first and a second optical transceiver at a dedicated end of the optical transmission link and an optical path connecting the first and second optical transceiver. The optical transceivers apply the methods of converting an electrical digital transmit signal into an electrical PAM-n transmit signal, pre-emphasizing the electrical PAM-n transmit signal) by digital filtering and using the pre-emphasized electrical PAM-n signal2) as modulating signal for optically modulating an optical carrier signal. The optical modulation method deployed is configured to create an optical PAM-n transmit signal with a positive or negative chirp. For initializing the optical transmission link (100), an initialization process is performed in which at least one loop including the following steps is run through creating, in the first optical transceiver, an optical PAM-n training transmit signal and transmitting it to the second optical transceiver, the optical PAM-n training transmit signal being created using an electrical PAM-n training transmit signal including a binary training sequence. Initial values for filter parameters are used for pre-emphasizing the electrical PAM-n training transmit signal and an initial value is used for a chirp parameter that defines the positive or negative chirp of the optical PAM-n training transmit signal receiving, in the second optical transceiver, the optical PAM-n training transmit signal as an optical PAM-n training receive signal using direct detection. The optical PAM-n training receive signal is converted into an electrical PAM-n training receive signal. The method includes obtaining sampled values of the electrical PAM-n training receive signal (RPel,1) by sampling this signal at predetermined points in time; and using the sampled values obtained and corresponding sampled values of an ideal electrical PAM-n transmit signal to determine operating values for the filter parameters and an operating value for the chirp parameter.

    Rollover of encryption keys in a packet-compatible network

    公开(公告)号:US11637699B2

    公开(公告)日:2023-04-25

    申请号:US17380149

    申请日:2021-07-20

    Abstract: There is provided a technique of establishing encryption keys for communication between 1st peer and 2nd peer via a data path. The technique comprises: by each peer, using input keying material to independently generate equivalent pairs of peer encryption keys (PEKs), verifying equivalence of the generated PEK pairs, and using by 1st peer and 2nd peer the verified PEK pairs to become in possession of equivalent pairs of session encryption keys (SEKs). Verifying comprises: generating by 1st peer a first handshake (HS) message encrypted by PEK Tx1 and sending the first HS message to the 2nd peer via the data path; decrypting by the 2nd peer the first HS message using the PEK Rx2, generating a second HS message encrypted by PEK Tx2, and sending the second HS message to the 1st peer via the data path; and decrypting the second HS message by the 1st peer using PEK Rx1.

    Transparent multiplexing of IP endpoints

    公开(公告)号:US11621917B2

    公开(公告)日:2023-04-04

    申请号:US17068664

    申请日:2020-10-12

    Abstract: Allowing a network function (such as a router, firewall or SD-WAN endpoint) or service chain of network functions to transparently access a network uplink, while also allowing a set of management entities to access the same link without interference or configuration. To the extent that a conflict arises between ports allocated to the management functions and to the network functions, the relevant port is automatically removed from use by management functions and allocated to network functions to end the conflict.

    Method and system of latency assessment in a packet data network

    公开(公告)号:US11095430B2

    公开(公告)日:2021-08-17

    申请号:US16591957

    申请日:2019-10-03

    Inventor: Andrew Sergeev

    Abstract: There are provided a method and system for assessing latency of ciphering end point of secure communication channel. The method comprises: generating a test traffic comprising a series of original data packets, wherein, for each original data packet, size of a given packet is uniquely indicative of the packet's place in a sequence of data packets in the series and enables unique correspondence with a size of the given packet upon its encryption; successively transmitting the original packets to the ciphering end point, whilst associating with respective departure time stamps; receiving encrypted packets from the ciphering end point and associating them with respective arrival time stamps; using a size of a given encrypted packet with a timestamp TSa to identify a size of a matching original packet, its place in the sequence of original packets and, thereby, its departure timestamp TSd, thus giving rise to a plurality of timestamp pairs (TSd; TSa).

    METHOD AND APPARATUS FOR CORRECTING A PACKET DELAY VARIATION

    公开(公告)号:US20210243129A1

    公开(公告)日:2021-08-05

    申请号:US17157407

    申请日:2021-01-25

    Abstract: A method and system of correcting a packet delay variation, PDV, of express traffic comprising high-priority express packets interspersed at a transmitter (2) by a preemption mechanism with a best-effort traffic comprising low-priority best-effort packets, wherein the method comprises the steps of: calculating (S1) at the transmitter (2) a preemption delay value, PRDV, which indicates a preemption delay, PD, introduced by the preemption mechanism; writing (S2) the calculated preemption delay value, PRDV, into a delay header field of a header of a high-priority express packet transmitted by said transmitter (2) via a signal line (4) to a receiver (3); extracting (S3) the preemption delay value, PRDV, from the delay header field of the header of the high-priority express packet received by the receiver (3) via the signal line (4) from the transmitter (2); calculating (S4) at the receiver (3) a variation compensation delay, VCD, value by subtracting the extracted preemption delay value, PRDV, from a predetermined worst-case preemption delay value, PRDVworst; and applying (S5) at the receiver an additional delay to the high-priority express packet according to the calculated variation compensation delay, VCD, value to compensate the preemption delay, PD, introduced by the preemption mechanism at the transmitter (2).

    Device and method of forwarding data packets in a virtual switch of a software-defined wide area network environment

    公开(公告)号:US10979367B2

    公开(公告)日:2021-04-13

    申请号:US16270163

    申请日:2019-02-07

    Abstract: A method, device, and computer-program product of forwarding data packets in a virtual switch is provided. The virtual switch comprises: first, second and third virtual ports for respectively receiving/transmitting: LAN traffic from/to a physical LAN port; secured traffic from/to a physical secured traffic port; and Internet traffic from/to a physical Internet port. The method comprises: determining, for selected data packets of the outbound traffic, signature information; storing the signature information and information identifying associated packets; outputting the outbound traffic for processing by a virtual machine; receiving at least a portion of the outbound traffic as outbound secured traffic for supply to the secured port; determining whether each data packet of the outbound secure traffic matches the dedicated signature information and responsively controlling the forwarding of the respective data packet as part of the outbound secured traffic to the secured port and/or creating a SUSPICIOUS SOURCE alarm.

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