U.S. patent application number 16/143052 was filed with the patent office on 2020-03-26 for method and apparatus for providing resiliency for delay sensitive services.
The applicant listed for this patent is NOKIA SOLUTIONS AND NETWORKS OY. Invention is credited to Andre POULIN, Kin-Yee WONG.
Application Number | 20200099550 16/143052 |
Document ID | / |
Family ID | 69884750 |
Filed Date | 2020-03-26 |
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United States Patent
Application |
20200099550 |
Kind Code |
A1 |
POULIN; Andre ; et
al. |
March 26, 2020 |
METHOD AND APPARATUS FOR PROVIDING RESILIENCY FOR DELAY SENSITIVE
SERVICES
Abstract
Various embodiments relate to a method and apparatus for
guaranteeing symmetrical delay in both directions for a
Time-Division Multiplexing Pseudowire ("TDM-PW") service on a
packet switching network ("PSN"), the method including the steps of
using a transport method to specify a first path including a
corresponding pair of unidirectional service tunnels for the TDM PW
service between a master router and a slave router, detecting a
failure on either of the corresponding pair of unidirectional
service tunnels of the first path between the master router and the
slave router, switching the master router and the slave router to a
second path including a corresponding pair of unidirectional
service tunnels, resetting a jitter buffer on the master router and
the slave router and adjusting the jitter buffer to a halfway
point, and transmitting and receiving data using the second path
including the corresponding pair of unidirectional service
tunnels.
Inventors: |
POULIN; Andre; (Gatineau,
CA) ; WONG; Kin-Yee; (Ottawa, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NOKIA SOLUTIONS AND NETWORKS OY |
Espoo |
|
FI |
|
|
Family ID: |
69884750 |
Appl. No.: |
16/143052 |
Filed: |
September 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 12/56 20130101;
H04L 47/724 20130101; H04L 45/22 20130101; H04L 2012/5649 20130101;
H04L 12/4633 20130101; H04L 2012/5648 20130101; H04L 47/283
20130101 |
International
Class: |
H04L 12/46 20060101
H04L012/46; H04L 12/841 20060101 H04L012/841; H04L 12/913 20060101
H04L012/913; H04L 12/707 20060101 H04L012/707; H04L 12/54 20060101
H04L012/54 |
Claims
1. A method for guaranteeing symmetrical delay in both directions
for a Time-Division Multiplexing Pseudowire ("TDM-PW") service on a
packet switching network ("PSN"), the method comprising the steps
of: using a transport method to specify a first path including a
corresponding pair of unidirectional service tunnels for the TDM PW
service between a master router and a slave router; detecting a
failure on either of the corresponding pair of unidirectional
service tunnels of the first path between the master router and the
slave router; switching the master router and the slave router to a
second path including a corresponding pair of unidirectional
service tunnels; resetting a jitter buffer on the master router and
the slave router and adjusting the jitter buffer to a halfway
point; and transmitting and receiving data using the second path
including the corresponding pair of unidirectional service
tunnels.
2. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, further comprising the
step of: running a Asymmetry Delay Compensation ("ADC") sampling
algorithm after switching to the second path.
3. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein detecting that
the first path is unavailable is by one of detection of a loss of
signal, bidirectional forwarding detection failure, label-switched
path being down and the pair of corresponding service tunnels of
the first path and the pair of corresponding service tunnels of the
second path being down.
4. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein the master router
and the slave router include the pair of corresponding service
tunnels of the first path and the pair of corresponding service
tunnels of the second path which provide the first path and the
second path between the master router and the slave router.
5. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein the first path
and the second path include two unidirectional label-switched paths
with strict hop-by-hop routing over the master router and the slave
router.
6. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein the TDM PW
service discards any data which is received on the second path
before the switching to the second path.
7. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein the TDM PW
service discards any data which is received on the first path after
the switching to the second path.
8. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein running the ADC
sampling algorithm adjusts the jitter buffer to a halfway
point.
9. The method for guaranteeing symmetrical delay in both directions
for a TDM PW service on a PSN of claim 1, wherein the jitter buffer
is reset through a control plane through internal control messaging
with in-band control messaging.
10. The method for guaranteeing symmetrical delay in both
directions for a TDM PW service on a PSN of claim 1, wherein the
jitter buffer is reset through a control plane through internal
control messaging with out-of-band control message through a
control plane communication channel.
11. The method for guaranteeing symmetrical delay in both
directions for a TDM PW service on a PSN of claim 1, wherein the
jitter buffer is reset through a dataplane including ingress
processing and egress processing.
12. A non-transitory computer readable medium storing program code
for guaranteeing symmetrical delay in both directions for a TDM PW
service on a PSN, the program code being executable by a processor
to perform operations comprising: using a transport method to
specify a first path including a corresponding pair of
unidirectional service tunnels for the TDM PW service between a
master router and a slave router; detecting a failure on either of
the corresponding pair of unidirectional service tunnels of the
first path between the master router and the slave router;
switching the master router and the slave router to a second path
including a corresponding pair of unidirectional service tunnels;
resetting a jitter buffer on the master router and the slave router
and adjusting the jitter buffer to a halfway point; and
transmitting and receiving data using the second path including the
corresponding pair of unidirectional service tunnels.
13. The non-transitory computer readable medium of claim 12,
further comprising: running a Asymmetry Delay Compensation ("ADC")
sampling algorithm after switching to the second path.
14. The non-transitory computer readable medium of claim 12,
wherein detecting that the first path is unavailable is by one of
detection of a loss of signal, bidirectional forwarding detection
failure, label-switched path being down and the pair of
corresponding service tunnels of the first path and the pair of
corresponding service tunnels of the second path being down.
15. The non-transitory computer readable medium of claim 12,
wherein the master router and the slave router include the pair of
corresponding service tunnels of the first path and the pair of
corresponding service tunnels of the second path which provide the
first path and the second path between the master router and the
slave router.
16. The non-transitory computer readable medium of claim 12,
wherein the first path and the second path include two
unidirectional label-switched paths with strict hop-by-hop routing
over the master router and the slave router.
17. The non-transitory computer readable medium of claim 12,
wherein the TDM PW service discards any data which is received on
the second path before the switching to the second path.
18. The non-transitory computer readable medium of claim 12,
wherein the TDM PW service discards any data which is received on
the first path after the switching to the second path.
19. The non-transitory computer readable medium of claim 12,
wherein running the ADC sampling algorithm adjusts the jitter
buffer to a halfway point.
20. The non-transitory computer readable medium of claim 12,
wherein the jitter buffer is reset a control plane through internal
control messaging with in-band control messaging.
21. The non-transitory computer readable medium of claim 12,
wherein the jitter buffer is reset through a control plane through
internal control messaging with out-of-band control message through
a control plane communication channel.
22. The non-transitory computer readable medium of claim 12,
wherein the jitter buffer is reset through a dataplane including
ingress processing and egress processing.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to providing symmetric
delay communication between teleprotection relays, and more
specifically, but not exclusively, changes required to IP/MPLS
network elements in order to provide symmetric delays.
BACKGROUND
[0002] Services and/or equipment in telecommunications networks may
require symmetrical communication, or identical latency in both
directions between two sites. For example, current differential
relay monitoring for teleprotection purposes requires symmetrical
communication channels for operation.
[0003] This type of equipment has typically been connected using
Time-Division Multiplexing ("TDM") Wide-Area Network ("WAN") and
currently these types of symmetry-sensitive devices may be
interconnected using packet-based networks, for example, IP/MPLS
WAN. In order to interconnect this type of equipment over a packet
switched network ("PSN"), TDM PseudoWire ("PW") is used, which uses
a jitter buffer to counter the effects of packet delay variation in
the network.
[0004] Guaranteeing symmetry over a packet switched network may
also be addressed by proper network design and also with features
such as Asymmetry Delay Compensation ("ADC") which is disclosed in
U.S. Pat. Pub. No. 2015/0172154 A1, which discloses guaranteeing
the symmetry of the jitter buffers for the TDM PW.
SUMMARY
[0005] A brief summary of various embodiments is presented below.
Embodiments address a method and apparatus for providing resiliency
for delay sensitive services.
[0006] A brief summary of various example embodiments is presented.
Some simplifications and omissions may be made in the following
summary, which is intended to highlight and introduce some aspects
of the various example embodiments, but not to limit the scope of
the invention.
[0007] Detailed descriptions of example embodiments adequate to
allow those of ordinary skill in the art to make and use the
inventive concepts will follow in later sections.
[0008] Various embodiments relate to a method for guaranteeing
symmetrical delay in both directions for a Time-Division
Multiplexing Pseudowire ("TDM-PW") service on a packet switching
network ("PSN"), the method including the steps of using a
transport method to specify a first path including a corresponding
pair of unidirectional service tunnels for the TDM PW service
between a master router and a slave router, detecting a failure on
either of the corresponding pair of unidirectional service tunnels
of the first path between the master router and the slave router,
switching the master router and the slave router to a second path
including a corresponding pair of unidirectional service tunnels,
resetting a jitter buffer on the master router and the slave router
and adjusting the jitter buffer to a halfway point and transmitting
and receiving data using the second path including the
corresponding pair of unidirectional service tunnels.
[0009] In an embodiment of the present disclosure, the method for
guaranteeing symmetrical delay in both directions for a TDM PW
service on a PSN, further including the step of running a Asymmetry
Delay Compensation ("ADC") sampling algorithm after switching to
the second path.
[0010] In an embodiment of the present disclosure, detecting that
the first path is unavailable is by one of detection of a loss of
signal, bidirectional forwarding detection failure, label-switched
path being down and the pair of corresponding service tunnels of
the first path and the pair of corresponding service tunnels of the
second path being down.
[0011] In an embodiment of the present disclosure, the master
router and the slave router include the pair of corresponding
service tunnels of the first path and the pair of corresponding
service tunnels of the second path which provide the first path and
the second path between the master router and the slave router.
[0012] In an embodiment of the present disclosure, the first path
and the second path include two unidirectional label-switched paths
with strict hop-by-hop routing over the master router and the slave
router.
[0013] In an embodiment of the present disclosure, the TDM PW
service discards any data which is received on the second path
before the switching to the second path.
[0014] In an embodiment of the present disclosure, the TDM PW
service discards any data which is received on the first path after
the switching to the second path.
[0015] In an embodiment of the present disclosure, running the ADC
sampling algorithm adjusts the jitter buffer to a halfway
point.
[0016] In an embodiment of the present disclosure, the jitter
buffer is reset through a control plane through internal control
messaging with in-band control messaging.
[0017] In an embodiment of the present disclosure, the jitter
buffer is reset through a control plane through internal control
messaging with out-of-band control message through a control plane
communication channel.
[0018] In an embodiment of the present disclosure, the jitter
buffer is reset through a dataplane including ingress processing
and egress processing.
[0019] Various embodiments relate to a non-transitory computer
readable medium storing program code for guaranteeing symmetrical
delay in both directions for a TDM PW service on a PSN, the program
code being executable by a processor to perform operations
including using a transport method to specify a first path
including a corresponding pair of unidirectional service tunnels
for the TDM PW service between a master router and a slave router,
detecting a failure on either of the corresponding pair of
unidirectional service tunnels of the first path between the master
router and the slave router, switching the master router and the
slave router to a second path including a corresponding pair of
unidirectional service tunnels, resetting a jitter buffer on the
master router and the slave router and adjusting the jitter buffer
to a halfway point and transmitting and receiving data using the
second path including the corresponding pair of unidirectional
service tunnels.
[0020] In an embodiment of the present disclosure, the
non-transitory computer readable medium, further including running
a Asymmetry Delay Compensation ("ADC") sampling algorithm after
switching to the second path.
[0021] In an embodiment of the present disclosure, detecting that
the first path is unavailable is by one of detection of a loss of
signal, bidirectional forwarding detection failure, label-switched
path being down and the pair of corresponding service tunnels of
the first path and the pair of corresponding service tunnels of the
second path being down.
[0022] In an embodiment of the present disclosure, the master
router and the slave router include the pair of corresponding
service tunnels of the first path and the pair of corresponding
service tunnels of the second path which provide the first path and
the second path between the master router and the slave router.
[0023] In an embodiment of the present disclosure, the first path
and the second path include two unidirectional label-switched paths
with strict hop-by-hop routing over the master router and the slave
router.
[0024] In an embodiment of the present disclosure, the TDM PW
service discards any data which is received on the second path
before the switching to the second path.
[0025] In an embodiment of the present disclosure, the TDM PW
service discards any data which is received on the first path after
the switching to the second path.
[0026] In an embodiment of the present disclosure, running the ADC
sampling algorithm adjusts the jitter buffer to a halfway
point.
[0027] In an embodiment of the present disclosure, the jitter
buffer is reset a control plane through internal control messaging
with in-band control messaging.
[0028] In an embodiment of the present disclosure, the jitter
buffer is reset through a control plane through internal control
messaging with out-of-band control message through a control plane
communication channel.
[0029] In an embodiment of the present disclosure, the jitter
buffer is reset through a dataplane including ingress processing
and egress processing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The accompanying figures, where like reference numerals
refer to identical or functionally similar elements throughout the
separate views, together with the detailed description below, are
incorporated in and form part of the specification, and serve to
further illustrate example embodiments of concepts found in the
claims, and explain various principles and advantages of those
embodiments.
[0031] These and other more detailed and specific features are more
fully disclosed in the following specification, reference being had
to the accompanying drawings, in which:
[0032] FIG. 1 illustrates a block diagram for multiple paths where
the TDM PW uses PW redundancy to ensure the same path is used in
the current embodiment;
[0033] FIG. 2 illustrates a block diagram where multiple paths
exist where traffic is received from the active service tunnel pair
in the current embodiment; and
[0034] FIGS. 3A, 3B, and 3C illustrate a block diagram where
multiple paths exist where there is deferred asymmetry after a path
switchover in the current embodiment;
[0035] FIGS. 4A and 4B illustrate a block diagram for the logical
elements of a dataplane TDM PW steady state and operational in the
current embodiment.
DETAILED DESCRIPTION
[0036] It should be understood that the figures are merely
schematic and are not drawn to scale. It should also be understood
that the same reference numerals are used throughout the figures to
indicate the same or similar parts.
[0037] The descriptions and drawings illustrate the principles of
various example embodiments. It will thus be appreciated that those
skilled in the art will be able to devise various arrangements
that, although not explicitly described or shown herein, embody the
principles of the invention and are included within its scope.
Furthermore, all examples recited herein are principally intended
expressly to be for pedagogical purposes to aid the reader in
understanding the principles of the invention and the concepts
contributed by the inventor to furthering the art and are to be
construed as being without limitation to such specifically recited
examples and conditions. Additionally, the term, "or," as used
herein, refers to a non-exclusive or (i.e., and/or), unless
otherwise indicated (e.g., "or else" or "or in the alternative").
Also, the various embodiments described herein are not necessarily
mutually exclusive, as some embodiments can be combined with one or
more other embodiments to form new embodiments. Descriptors such as
"first," "second," "third," etc., are not meant to limit the order
of elements discussed, are used to distinguish one element from the
next, and are generally interchangeable.
[0038] For example, in order to provide symmetry for a TDM PW,
which may be used for teleprotection over the PSN, the network
design must guarantee that both directions of the transportation
method for the TDM PW traverses the network through the same nodes
and the same interfaces. Therefore, the transportation method,
whether unidirectional or bidirectional, must provide the ability
to specify the path for the TDM PW in order to provide
symmetry.
[0039] For example, using Resource Reservation Protocol with
Traffic Engineering ("RSVP-TE") with strict hops provides symmetry.
Therefore by using both RSVP-TE strict hop LSP to transport the TDM
PW for the teleprotection and by using an ADC feature to guarantee
jitter buffer symmetry, the latency in both directions is within
the tolerance limit of the symmetry sensitive devices.
[0040] However, resiliency may also be required to guarantee
functionality of the teleprotection equipment when the packet
switched network experiences unexpected failures. Symmetry must
also be maintained after switching to the protection path, which
the resiliency method does not provide.
[0041] Many transportation methods may provide their own resiliency
methods including fast switch times, but these types of methods may
not be meeting the requirement of symmetry for teleprotection
devices, for example, RSVP-TE with Fast Reroute ("FRR").
[0042] When performing corrective action on the protection path at
the point of local repair ("PLR"), the corrective action only
occurs in a single direction, because RSVP LSP are unidirectional
in nature and therefore, the corrective action may only modify the
latency in a single direction which would cause asymmetry. The
asymmetry is detected by the teleprotection equipment which may
erroneously determine that the power line being monitored are in a
problematic state and would take corrective actions, for example,
shut down the section of the power lines which are not in a
problematic state.
[0043] Therefore, the resiliency method for the transport of the
TDM PW used for teleprotection devices must be required to perform
corrective action in both directions to guarantee symmetry on the
TDM PW.
[0044] For example, a bidirectional resiliency method which is
required to guarantee symmetry on the TDM PW is pseudowire
redundancy with a Master-Slave relationship. The pseudowire
redundancy method allows for the setup of multiple endpoints, each
endpoint being a corresponding pair of unidirectional service
tunnels, called service tunnel pair for the rest of this document,
for a TDM PW service. The pseudowire redundancy with the
Master-Slave relationship allows a Master to control which service
tunnel pair is the active endpoint and therefore, the slave will
only switch to a protection service tunnel pair when requested to
from the Master.
[0045] By having multiple redundant service tunnel pairs, each path
for the transportation method may be specified. The trigger to
switch to a protection path may come from different sources, for
example, from bidirectional forwarding detection ("BFD"), open
shortest path first ("OSPF") or local port status.
[0046] FIG. 1 illustrates a block diagram 100 for multiple paths
where the TDM PW uses PW redundancy to ensure the same path is used
in the current embodiment.
[0047] In the current embodiment, by enabling PW redundancy in an
active/protection mode for the TDM PW service with a single or
multiple service access point and at least two service tunnels
pairs with unique paths for each router, the same path is used. One
of the routers is designated as the Signaling-Master or Master 101
and the other routers is designated as the Signaling-Slave or Slave
102. The two service tunnel pairs from each router provide two
paths between the two routers. Path 1 103 has a symmetrical delay
of d1 msec and Path 2 104 has a symmetrical delay of d2 msec. Each
path includes two unidirectional LSPs with strict hop-by-hop
routing over the same router and preferably over the same
interface.
[0048] The path may be detected as unavailable by loss of signal
("LOS"), bidirectional forwarding detection ("BFD") failure, label
switch path ("LSP") failure, interior gateway protocol ("IGP")
failures and service tunnel failure.
[0049] When the TDM PW switches to a protection path, the Master
101 sends a request to the Slave 102 to switch to the protection
path and therefore, symmetry is guaranteed if both endpoints only
transmit on the active service tunnel pair and only receive from
the active service tunnel pair.
[0050] In the current embodiment, the receiving side may accept
traffic from the active and all protection endpoints in order to
provide a faster switch time. However, the symmetry may be
compromised since traffic would be accepted from two different
service tunnel pairs which may affect the jitter buffer level, if
the jitter buffer never underruns. If the jitter buffer never
underruns, the latency in both directions may be different and the
teleprotection devices may detect that difference in latency and
take a corrective action, however, this is a false-positive
corrective action from the teleprotection device.
[0051] Currently, when Path 1 103 is used as an active path, a path
failure may occur which invokes an automatic recovery for the TDM
service to switch to Path 2 104. However, if the switch from Path 1
103 to Path 2 104 is fast enough, there may be no underrun of the
jitter buffer in one or both directions. The total service latency
may not have changed; however, the average jitter buffer fill may
no longer be at the middle point and no longer result in the
"engineered" jitter buffer latency.
[0052] Therefore, when the TDM resets, for example, when it
underruns or overruns, the ADC will reset the jitter buffer latency
to be correct, which will cause an asymmetry if one direction was
reset and the other direction was not reset.
[0053] PW redundancy may allow reception of packets from both the
active and the protection paths, meaning the transmit direction has
changed. However, since the communication between the Master 101
and the Slave 102 is not instantaneous, the switching of the path
may be slightly delayed in one direction and any existing packets
may also be delayed, which may cause asymmetry.
[0054] The current embodiment is directed towards ensuring
symmetrical delay in both directions when using resiliency with a
TDM PW service between the relays. In the current embodiment, the
Master 101 and Slave 102 are transmitting and receiving on the same
service tunnels pair and when switching to a protection path, the
same behavior is applied for transmission and reception of packets.
Further, the current embodiment is directed towards the jitter
buffer latency being symmetrical at both ends of the TDM PW and
therefore upon switching to the protection path, the TDM PW jitter
buffer must be reset and filled to the expected halfway point.
[0055] FIG. 2 illustrates a block diagram 200 where multiple paths
exist where traffic is received from the active service tunnel in
the current embodiment.
[0056] The block diagram 200 includes a Master 201, Slave 202, Path
1 203 which has a symmetrical delay of d1 msec and Path 2 204 which
has a symmetrical delay of d2 msec.
[0057] The software for the TDM PW service may be modified to
discard any packets received on the service tunnel pair that is not
the active path.
[0058] However, by applying this change to all PW or even to all
TDM PW, the change may impact and degrade the switch time.
Therefore, since this requirement is only for latency sensitive
devices, this requirement may only be applied to TDM PW, which are
used for latency sensitive devices.
[0059] When switching to the protection path, coordinating the
switch between the Master 201 and the Slave 202 at the same precise
time is difficult and packet loss may occur after a PSN failure,
therefore, it is difficult to guarantee that the jitter buffer
latency at both ends of the TDM PW have the same delay. Therefore,
the current embodiment is directed towards resetting the jitter
buffer at both ends and may restart the ADC sampling algorithm.
[0060] FIG. 3C illustrates a block diagram 300 where multiple paths
exist where there is deferred asymmetry after a path switchover in
the current embodiment.
[0061] In order to avoid a deferred asymmetry, the TDM service may
automatically reset the jitter buffer and run ADC after a
switchover to a different path, if the ADC is enabled for the TDM
PW.
[0062] For example, FIG. 3A illustrates the jitter buffer 305 at
Slave 302 when using Path 1 303 at a halfway point and FIG. 3B
illustrates the jitter buffer 305 at Slave 302 after switching to
protection path 304 where the jitter buffer 305 is below the
halfway point which causes the deferred asymmetry.
[0063] When the receiving end switches to a new protection path, or
when the receiving end switches to a new active path, the jitter
buffer must be reset at the Master 301 and Slave 302 ends and
restart the algorithm to bring the jitter buffer to the expected
half way point.
[0064] The block diagram includes a Master 301, Slave 302, Path 1
303 which has a symmetrical delay of d1 msec and Path 2 304 which
has a symmetrical delay of d2 msec.
[0065] In order to reset the algorithm to bring the jitter buffer
to the expected half way point, there are two methods that may be
employed. It may be reset using the control plane or the
dataplane.
[0066] When using the control plane and when the Master 301 or
Slave 302 switch their transmission and reception to a new
protection path or to an active path, the jitter buffer in the
datapath may be reset through internal control messaging either
with in-band control messaging through the fabric or out-of-band
control messaging through dedicated control plane communication
channel.
[0067] Teleprotection device may declare a false-positive with this
type of implementation in the current embodiment, if the jitter
buffer has a different latency than the opposite direction path,
because of delays in the communication between the Master 301 and
the Slave 302 and delays in processing control messages.
[0068] When using the dataplane, the dataplane may be represented
by logical elements such as ingress processing, egress processing
and switch fabric. These elements may reside in different hardware
entities in the system or even within the same hardware entity. It
may reside in a cloud networking architecture implementing a
Network Function Virtualization ("NFV").
[0069] FIGS. 4A and 4B illustrate a block diagram 400 for the
logical elements of a dataplane TDM PW steady state and operational
in the current embodiment.
[0070] FIG. 4A includes two paths, an active path 401 and a
protection path 402. The active path 401 transmits the ID=100 from
ingress processing 403, to switch fabric 404 to egress processing
405, which includes the jitter buffer 406 and to the teleprotection
device 407.
[0071] The TDM PW accepts traffic from a single service tunnel
pair, which is the active path at all time, the ID is sent to the
egress processing for the egress processing to monitor any changes
in the ID.
[0072] Upon a change in the active service tunnel pair, both ends
of the TDM PW may start transmitting on the new active path (i.e.,
the protection path 402). Each of the TDM PW are monitoring the
active service tunnel pair, on the egress processing 405 side, for
a change in service tunnel pair ID.
[0073] When the first packet is received from the new active path
(i.e. the protection path 402), the egress processing 405 may
detect the change and reset the jitter buffer 406, which is
emptying the jitter buffer, restarting the leveling algorithm and
losing communication between the teleprotection devices.
[0074] FIG. 4B includes the active path 410 (previously the
protection path 402). During the leveling of the jitter buffer 406,
communication with the teleprotection device 407 will be lost which
prevents the teleprotection device 407 from declaring a false
positive.
[0075] Once the jitter buffer 406 leveling algorithm has completed,
the communication with the teleprotection device 407 is restored
and if both ends of the TDM PW have completed the leveling
algorithm, the two teleprotection devices may communicate.
[0076] When using the dataplane method, the control plane
intervention is not required and the jitter buffer reset is
instantaneous, with the first packet received on the active path
410. The current embodiment provides an immunity to network changes
where if the active path was to change rapidly, it would be reset
again on the first packet of the newly active path and there would
not be any case where the TDM PW latency would be asymmetrical.
[0077] The embodiments described herein may be implemented as
software running on a processor with an associated memory and
storage. The processor may be any hardware device capable of
executing instructions stored in memory or storage or otherwise
processing data. As such, the processor may include a
microprocessor, field programmable gate array (FPGA),
application-specific integrated circuit (ASIC), graphics processing
units (GPU), specialized neural network processors, cloud computing
systems, or other similar devices.
[0078] The memory may include various memories such as, for example
L1, L2, or L3 cache or system memory. As such, the memory may
include static random-access memory (SRAM), dynamic RAM (DRAM),
flash memory, read only memory (ROM), or other similar memory
devices.
[0079] The storage may include one or more machine-readable storage
media such as read-only memory (ROM), random-access memory (RAM),
magnetic disk storage media, optical storage media, flash-memory
devices, or similar storage media. In various embodiments, the
storage may store instructions for execution by the processor or
data upon with the processor may operate. This software may
implement the various embodiments described.
[0080] Further such embodiments may be implemented on
multiprocessor computer systems, distributed computer systems, and
cloud computing systems. For example, the embodiments may be
implemented as software on a server, a specific computer, on a
cloud computing, or other computing platform.
[0081] Any combination of specific software running on a processor
to implement the embodiments of the invention, constitute a
specific dedicated machine.
[0082] As used herein, the term "non-transitory machine-readable
storage medium" will be understood to exclude a transitory
propagation signal but to include all forms of volatile and
non-volatile memory.
[0083] It should be appreciated by those skilled in the art that
any blocks and block diagrams herein represent conceptual views of
illustrative circuitry embodying the principles of the invention.
Implementation of particular blocks can vary while they can be
implemented in the hardware or software domain without limiting the
scope of the invention.
[0084] Accordingly, it is to be understood that the above
description is intended to be illustrative and not restrictive.
Many embodiments and applications other than the examples provided
would be apparent upon reading the above description. The scope
should be determined, not with reference to the above description
or Abstract below, but should instead be determined with reference
to the appended claims, along with the full scope of equivalents to
which such claims are entitled. It is anticipated and intended that
future developments will occur in the technologies discussed
herein, and that the disclosed systems and methods will be
incorporated into such future embodiments. In sum, it should be
understood that the application is capable of modification and
variation.
[0085] The benefits, advantages, solutions to problems, and any
element(s) that may cause any benefit, advantage, or solution to
occur or become more pronounced are not to be construed as a
critical, required, or essential features or elements of any or all
the claims. The invention is defined solely by the appended claims
including any amendments made during the pendency of this
application and all equivalents of those claims as issued.
[0086] All terms used in the claims are intended to be given their
broadest reasonable constructions and their ordinary meanings as
understood by those knowledgeable in the technologies described
herein unless an explicit indication to the contrary in made
herein. In particular, use of the singular articles such as "a,"
"the," "said," etc. should be read to recite one or more of the
indicated elements unless a claim recites an explicit limitation to
the contrary.
[0087] The Abstract of the Disclosure is provided to allow the
reader to quickly ascertain the nature of the technical disclosure.
It is submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. In addition,
in the foregoing Detailed Description, it can be seen that various
features are grouped together in various embodiments for the
purpose of streamlining the disclosure. This method of disclosure
is not to be interpreted as reflecting an intention that the
claimed embodiments require more features than are expressly
recited in each claim. Rather, as the following claims reflect,
inventive subject matter lies in less than all features of a single
disclosed embodiment. Thus the following claims are hereby
incorporated into the Detailed Description, with each claim
standing on its own as a separately claimed subject matter.
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