WO2019201013A1 - 一种网络故障保护的方法、系统和存储介质 - Google Patents

一种网络故障保护的方法、系统和存储介质 Download PDF

Info

Publication number
WO2019201013A1
WO2019201013A1 PCT/CN2019/075689 CN2019075689W WO2019201013A1 WO 2019201013 A1 WO2019201013 A1 WO 2019201013A1 CN 2019075689 W CN2019075689 W CN 2019075689W WO 2019201013 A1 WO2019201013 A1 WO 2019201013A1
Authority
WO
WIPO (PCT)
Prior art keywords
bier
forwarding
bit position
link
brft
Prior art date
Application number
PCT/CN2019/075689
Other languages
English (en)
French (fr)
Inventor
韩玉芳
Original Assignee
中兴通讯股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中兴通讯股份有限公司 filed Critical 中兴通讯股份有限公司
Priority to US17/044,452 priority Critical patent/US11502896B2/en
Publication of WO2019201013A1 publication Critical patent/WO2019201013A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/28—Routing or path finding of packets in data switching networks using route fault recovery
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/06—Management of faults, events, alarms or notifications
    • H04L41/0631—Management of faults, events, alarms or notifications using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis
    • H04L41/065—Management of faults, events, alarms or notifications using root cause analysis; using analysis of correlation between notifications, alarms or events based on decision criteria, e.g. hierarchy, tree or time analysis involving logical or physical relationship, e.g. grouping and hierarchies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/06—Management of faults, events, alarms or notifications
    • H04L41/0654—Management of faults, events, alarms or notifications using network fault recovery
    • H04L41/0663—Performing the actions predefined by failover planning, e.g. switching to standby network elements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/74—Address processing for routing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/74—Address processing for routing
    • H04L45/745—Address table lookup; Address filtering
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L2001/0092—Error control systems characterised by the topology of the transmission link
    • H04L2001/0095—Ring

Definitions

  • the present disclosure relates to the field of network technologies, and in particular, to a method, system, and storage medium for network fault protection in Bit Index Explicit Replication Traffic Engineering (BIER-TE).
  • BIER-TE Bit Index Explicit Replication Traffic Engineering
  • the BIER-TE proposed in the Draft-Eckert-Bier-Te-Arch is a traffic engineering-based BIER forwarding architecture. It introduces the BIER-TE controller layer based on the BIER and sends the forwarding table through the controller. Use the Path Computation Element (PCE) to plan the optimal path according to the requirements and forward the packets in an explicit hop-by-hop mode to make network traffic control more flexible.
  • PCE Path Computation Element
  • Another document Draft-Eckert-Bier-Te-Frr provides three measures for BIER-TE network fault protection, including Point-to-Point Tunneling (PPT), Baotou. Modified (Header Modification, HM) and BIER-in-BIER Encapsulation (BBE), these three fault protection schemes have their own advantages, but there are still deficiencies.
  • the main purpose of the present disclosure is to provide a method, system and storage medium for network fault protection, which aims to bypass the fault forwarding link and ensure the BIER report when the BIER message is forwarded by protecting the ring bit position and adding a new BRFT.
  • the text is successfully forwarded to each normal node of the ring topology.
  • an embodiment of the present disclosure provides a method for network fault protection, the method comprising the steps of: assigning a guard ring bit position to each forwarding link of a ring topology, the direction of the guard ring bit position and Correspondingly, the working path of the forwarding link is reversed; a BIER Ring Forwarding Table (BRFT) is added, and the BRFT is used to store the adjacent forwarding in the direction of the bit position of the protection ring. If the BIER Forwarding Router (BFR) detects that a downstream adjacency of a forwarding link has failed, then the BIER-TE adjacency fast reroute is found when the BIER packet is forwarded along the working path.
  • BFR BIER Forwarding Router
  • BIER-TE Adjacency FRR Table BTAFT
  • an embodiment of the present disclosure further provides a system for network fault protection, the system comprising: a BIER-TE controller, configured to allocate a guard ring bit position for each forwarding link of a ring topology, The direction of the protection ring bit position is opposite to the working path of the corresponding forwarding link, and a BIER ring forwarding table BRFT is added, and the BRFT is used for storing the adjacent forwarding related in the direction of the protection ring bit position.
  • the item is delivered, and the BIER packet forwarding related entry is sent to the BIER forwarding router through the southbound interface; the BIER forwarding router is configured to receive the BIER packet sent by the BIER-TE controller through the southbound interface.
  • the BIER-TE adjacency fast rerouting table BTAFT is forwarded when the BIER packet is forwarded along the working path.
  • the content of the entry find the correspondence between the link bit position of the faulty forwarding link and the protection ring bit position, and combine the BIER report with the contents of the BRFT entry. Forward to the end point of failure along the direction of the guard ring bit position.
  • the present disclosure provides a storage medium for computer readable storage, the storage medium storing one or more programs, the one or more programs being executable by one or more processors, To achieve the steps of the foregoing method.
  • the method, system and storage medium for network fault protection in BIER-TE proposed by the present disclosure, which allocates a guard ring bit position for each forwarding link of the ring topology, wherein the direction of the protection ring bit position and the corresponding forwarding link
  • the working path is set oppositely.
  • a BIER ring forwarding table BRFT is added to store the adjacent forwarding entries related to forwarding in the direction of the protection ring bit position. In this way, when the BIER packet is forwarded along the working path, if the BIER forwarding router BFR detects that the downstream neighbor of a forwarding link fails, the content of the BIER-TE adjacency fast rerouting table BTAFT is searched.
  • the BIER packet can be forwarded to bypass the fault forwarding link, ensuring that the BIER packet is successfully forwarded to each normal node in the ring topology.
  • FIG. 1 is a flowchart of a method for network fault protection according to Embodiment 1 of the present disclosure.
  • FIG. 3 is a general flow chart of the BIER-TE fault protection control plane of the present disclosure.
  • FIG. 4 is a flow chart of the BIER-TE protection ring BitPosition allocation and the BRFT entry setting of the present disclosure.
  • Figure 5 is a dual ring dual node topology diagram of the present disclosure.
  • FIG. 6 is a flowchart of the integration and delivery of the BRFT entry of the present disclosure.
  • FIG. 7 is a flow chart of forming a BTAFT entry of the present disclosure.
  • Figure 8 is a flow chart of the BIER-TE FRR forwarding of the present disclosure.
  • FIG. 9 is a flow chart of the BRFT forwarding of the present disclosure.
  • FIG. 10 is a structural block diagram of a system for network fault protection according to Embodiment 2 of the present disclosure.
  • FIG. 11 is a schematic structural diagram of a four-ring topology according to an embodiment of the present disclosure.
  • FIG. 12 is a schematic structural diagram of a five-ring topology according to an embodiment of the present disclosure.
  • FIG. 13 is a schematic structural diagram of a six-ring topology according to an embodiment of the present disclosure.
  • FIG. 14 is a schematic structural diagram of an eight-ring topology according to an embodiment of the present disclosure.
  • FIG. 15 is a schematic diagram of a multicast service traffic path when the single-ring topology link in FIG. 14 is faulty.
  • FIG. 16 is a schematic diagram of a multicast service traffic path when the single-ring topology node in FIG. 14 fails.
  • 17 is a schematic structural diagram of a nine-ring topology according to an embodiment of the present disclosure.
  • FIG. 18 is a schematic diagram of a multicast service traffic path when the dual-ring topology link in FIG. 17 is faulty.
  • FIG. 19 is a schematic diagram of a multicast service traffic path when the dual-ring topology node in FIG. 17 fails.
  • 20 is a schematic structural diagram of a nine-ring topology according to an embodiment of the present disclosure.
  • FIG. 21 is a schematic diagram of a multicast service traffic path when the dual-ring topology link in FIG. 20 is faulty.
  • FIG. 22 is a schematic diagram of a multicast service traffic path when the dual-ring topology node shown in FIG. 20 is faulty.
  • BRFT table 23 is a simplified example of a BRFT table according to the first embodiment.
  • Figure 24 is a diagram showing a simplified example of a BTAFT table according to the first embodiment.
  • FIG. 27 is a BRFT entry on each node after integration according to Embodiment 5.
  • FIG. 29 is a simplified diagram of a BIER header according to Embodiment 7.
  • module means a module
  • component means a component
  • unit means a unit in which the suffixes such as "module,” “component,” or “unit” used to denote an element are merely illustrative of the present disclosure, and have no particular meaning in themselves. Therefore, “module”, “component” or “unit” can be used in combination.
  • this embodiment provides a method for network fault protection in BIER-TE, and the method includes the following steps:
  • Step S110 Allocating a guard ring bit position for each forwarding link of the ring topology, and the direction of the guard ring bit position is opposite to the working path of the corresponding forwarding link.
  • the network fault is protected in the BIER-TE (Bit Index Explicit Replication Traffic Engineering) based on the ring network protection idea.
  • BFR BIER Forwarding Router
  • FIG. 2 which allocates a link bit position (BitPosition, BP) and a guard ring bit position for each forwarding link of the ring topology, where The direction of the link bit position is the working path of the corresponding forwarding link, and the direction of the guard ring bit position is opposite to the direction of the link bit position, that is, the direction of the guard ring bit position is opposite to the working path of the corresponding forwarding link.
  • BP link bit position
  • BP guard ring bit position
  • the link bit position (BitPosition, BP) is clockwise, and the guard ring bit position in the opposite direction is used (the large ring line in the figure) Protection in the direction shown), that is, protection by the guard ring bit position in the counterclockwise direction; and for the forwarding link in the A to C direction, the link bit position (BitPosition, BP) is counterclockwise,
  • the guard ring bit position (the direction indicated by the small circle line in the figure) is protected in the opposite direction, that is, protected by the clockwise guard ring bit position (in the figure).
  • the guard ring bit position and the link bit position of the protected forwarding link need to belong to the same ⁇ SD:BSL:SI> set.
  • the allocation and sharing of the protection ring bit positions should specifically follow the following rules: If the forwarding link protected by the ring topology is a Special Interconnected-link, the corresponding protection ring bit positions cannot be shared. Outside the link, the corresponding assigned guard ring bit positions can be shared.
  • Step S120 Add a BIER ring forwarding table BRFT, which is used to store the adjacent forwarding entries related to forwarding in the direction of the protection ring bit position.
  • a BIER Ring Forwarding Table (BRFT) is added, which is mainly used to store adjacent forwarding entries related to the forwarding of the bit position of the protection ring.
  • BRFT BIER Ring Forwarding Table
  • the BRFT table includes at least the following items:
  • Bit index Index information BIER-TE BIFT (Bit Index Forwarding Table), a BIFT-id corresponds to a BRFT table, and the bit index Index information indicates a bit index corresponding to the BitPosition in the table;
  • Adjacent Adjacencies information BIER-TE BIFT (Bit Index Forwarding Table), indicating information related to the adjacency, such as tags, ports, etc.
  • DNR Do Not Reset
  • bit mask C-BM (Clear-BitMask) information that needs to be cleared when forwarding: similar to F-BM, in the data forwarding according to the forwarding rules, bit string (BitString) and C-BM to obtain a new bit string ( BitString);
  • Status of the entry status The status of the entry related to the detection.
  • the fast detection status of the link is associated with the related entry.
  • the content of the entry of the BRFT may be specifically formed by performing a BRFT table configuration on each node through which the protection ring bit position passes according to the allocation process of the guard ring bit position. Further, according to the link type of the protected forwarding link (Special Interconnected-link and normal link), the closed loop and the non-closed loop are found, and for the non-closed loop, on the loop
  • the DNR (Do Not Reset) information of the DS-NNHs link is set to F
  • the DNR (Do Not Reset) information of the remaining links is set to T.
  • the closed loop the DNR (Do Not Reset) information of all links on the ring is set. All are T (closed loop), and the bit mask C-BM information that needs to be cleared when forwarding the message is set to the bit string corresponding to the guard ring bit position.
  • Step S130 When the BIER packet is forwarded along the working path, if the BIER forwarding router detects that the downstream neighbor of the forwarding link is faulty, the BIER-TE adjacency fast rerouting table BTAFT is searched for, The mapping between the link bit position of the faulty forwarding link and the bit position of the guard ring is found, and the BIER message is forwarded along the bit position of the guard ring to the opposite fault point in combination with the content of the BRFT entry. .
  • Each of the forwarding links in the ring topology uses fast detection techniques (such as BFD or Layer 2 link fast detection) to detect connectivity and correlate with the BRFT and BIFT BIER-TE Adjacency (adjacency) configured on it. This is not within the scope of this disclosure, so it will not be described too much here.
  • the BIER packet forwarding related entries (such as BIFT, BRFT, BTAFT, etc.) are sent to the BIER forwarding through the southbound interface (NETCONF/RESTCONF/PCEP/BGP-LS, etc.). Router BFR, so that the BIER message is forwarded on the BIER forwarding router.
  • the BIER packet of this embodiment is forwarded along the working path (ie, the direction of the link bit position) under normal conditions, and is forwarded along the guard ring path (ie, the direction of the guard ring bit position) when there is a fault.
  • the BIER packet header may be extended before the step, and the BIER packet is added along the working path (ie, the link bit position) by adding a new field.
  • Direction is also forwarded along the guard ring bit position. For example, a P field is added in the header of the BIER packet to distinguish whether the BIER message is forwarded along the working path or along the guard ring bit position, if the BIER message is along the guard ring bit.
  • the P field flag is set. If the BIER message is along the working path or needs to be separated from the guard ring bit position, the P field flag is cleared.
  • the addition of the P field can be achieved by using one or more bits of the BIER message header reserved field, but is not limited to other methods.
  • BTAFT BIER-TE Adjacency FRR Table
  • BFR BIER Forwarding Router
  • Reset BitMask modify the bit string content of the BIER message, replace the link bit position of the faulty forwarding link with the guard ring bit position of the faulty forwarding link, and report the BIER
  • the new field in the header ie, the P field
  • the BIER message is forwarded to the opposite fault point along the guard ring path (ie, the direction of the guard ring bit position) in combination with the contents of the BRFT entry.
  • the BIER message does not continue to be forwarded along the guard ring path.
  • the BIER message is transferred from the guard ring path (ie, the direction of the guard ring bit position) to the normal working path (ie, In the direction of the link bit position, the fault point can be bypassed by the above method, and the subsequent forwarding can be performed according to the original path.
  • the Bier-TE controller (Controller) is mainly used to process the control plane information. It sends the corresponding BIER forwarding router BFR through the southbound interface (NETCONF/RESTCONF/PCEP/BGP-LS, etc.). Configuration information (such as BIFT, BRFT, BTAFT tables, etc.). The following processes are all completed by the Bier-TE Controller.
  • the general control flow is shown in Figure 3.
  • Node 101 Select the protected BitPosition (ie, the link bit position of the protected forwarding link), assign a guard ring BitPosition (ie, protect the ring bit position), and set the content of the BRFT entry.
  • the protected BitPosition ie, the link bit position of the protected forwarding link
  • assign a guard ring BitPosition ie, protect the ring bit position
  • Node 102 The BRFT entry is integrated and sent to the BIER forwarding router through the southbound interface.
  • Node 103 Forms a BTAFT entry and sends it to the BIER forwarding router through the southbound interface.
  • Node 201 BitPosition (ie, link bit position) to be protected on BFRx (representing a protection point of the BIER forwarding router), called X ⁇ SD:BSL:SI> , respectively calculating BFR to X ⁇ SD:BSL: SI> downstream next-hop (DS-NH) and downstream next-hops (DS-NNHs) paths, respectively called P x-NH , P x-NNH1 , P x-NNH2... ; then go to step (2); where the P x-NH path cannot pass the link of X ⁇ SD:BSL:SI> ; P x-NNH1 , P x-NNH2...
  • Node 202 determining whether the link where X ⁇ SD:BSL:SI> is a Special Interconnected-link, if so, to node 203, otherwise to step node 204;
  • Node 203 for the paths P x-NH , P x-NNH1 , P x-NNH2... , sequentially determine whether the loop R (d, x-NH) or R (d, x-NNH1) , R (d,x-NNH2)& (d indicates direction, c is clockwise, a is counterclockwise) Assign BitPosition corresponding to ⁇ SD:BSL:SI>, R (d, x-NH) ring configuration on each link Corresponding BRFT entry, DNR marker position T; ring R (d, x-NNH1) , R (d, x-NNH2) ...
  • At least one ring and R (d, x-NH) are the same, and the R (d, x-NH) is not the same ring R (d, x-NNH) , and the BRFT entry is configured at the node corresponding to the P x-NNH passing through, where the DNR mark is located on the DS-NNHs node, and the remaining nodes are placed.
  • T; C-BM is set to the BitString corresponding to the ring BP (ie, the guard ring bit position) (the adjacency information is the same as BIFT, no special processing, no more retelling), and the process ends;
  • Node 204 for the paths P x-NH , P x-NNH1 , P x-NNH2... , sequentially determine whether the loop R d-NH or R (d, x-NNH1) , R (d, x) -NNH2)& (d indicates direction, c is clockwise, a is counterclockwise) Assign BitPosition corresponding to ⁇ SD:BSL:SI>, if the direction has been assigned BitPosition, the flow ends; otherwise, go to step node 205;
  • Node 205 assign a corresponding BitPosition (ring R (d, x-NNH1) , R to the above ring R (d, x-NH) , R (d, x-NNH1) , R (d, x-NNH2) (d, x-NNH2) ... at least one of the rings is the same as R (d, x-NH) , just assign a BitPosition), ring R (d, x-NH) , R (d, x-NNH1 ) , R (d, x-NNH2) ...
  • the DNR flag bits are all set to T (that is, all are closed loops), and the C-BM is set to ring BP (ie, the guard ring bit position)
  • the corresponding BitString (the adjacency information is the same as BIFT, no special processing, no more retelling), and the process ends.
  • Special Interconnected-link is the term proposed in this disclosure. If the number of DS-NNH nodes is greater than or equal to 2, the link is Special Interconnected-link.
  • the TE-FRR protection of the Special Interconnected-link is different from the general link, and some or some guard ring bit positions of the link bit position (BitPosition) are not shared (the guard ring is a non-closed ring, The corresponding table entry flag DNR information has F set), and the protection loops of other BitPositions are closed loops (all the link correspondence entries on the ring mark DNR information are all T), which can be shared.
  • One of the typical topologies of the Special Interconnected-link is a dual-ring two-node topology, as shown in Figure 5.
  • the link L in the figure is Special Interconnected-link.
  • the protection scheme proposed by the present disclosure is related to the topology, and sometimes multiple protection rings are required.
  • BFRs multiple ring-passing nodes
  • BRFT entries which are in the packet forwarding process. You need to select the appropriate entry and forward it according to the contents of its entry.
  • Figure 6 The integration and delivery process of BRFT entries is shown in Figure 6, which is described as follows:
  • the node 301 is connected to the protection loop BitPosition allocation and the BRFT entry configuration process, and the adjacent information in the BRFT item, the DNR flag, and the C-BM are configured.
  • Node 302 sequentially determining whether the BRFT entry associated with the protected BitPosition (ie, the link bit position) on each node satisfies the condition C1, satisfies the transit node 303, and otherwise proceeds to step node 304;
  • Node 303 Calculate C-BM of these entries according to formula 1;
  • the node After the content of each field of the BRFT entry on the node is updated and determined, the node forwards the item to the BIER through the southbound interface;
  • Node 305 Transfer to step node 302 to enter the next node processing flow
  • Node 306 All the BRFT entries of all the nodes are delivered, and the process ends.
  • condition C1 is as follows:
  • the number of entries with the DNR flag T on a BFR link is greater than 1.
  • the BFR link is a non-PLR (Point of Local-Repair), or the neighboring interface in the related entry is the same.
  • Index x, y, z are used to indicate the index of the BRFT entry related to the protected BitPosition (ie, the link bit position) on a BFR, and the C-BM index indicates the C-BM of the entry, assuming that the BRF is x, y, z.
  • the node 401 after calculating the protection ring path, the allocation protection ring BitPosition, and the issuing the BRFT entry process, respectively calculating the Add BitMask and the Reset BitMask values in the BTAFT entry;
  • Add BitMask is a bit string (BitString) composed of one or more guard rings BitPosition calculated in the above process;
  • Reset BitMask is a bit string of BitPosition (ie, the link bit position of the protected forwarding link) and a BitPosition corresponding to the DS-NNHs of the DS-NH to DNR flag F (BitString) );
  • the node 404 delivers a BTAFT entry to the BFRx through the southbound interface, and the FRR adjacency represents the protected BitPosition, and fills the corresponding entry with the calculated Add BitMask and Reset BitMask.
  • Node 501 The BFR receives the BIER message, and combines the BitString (bit string) in the message to find out which downstream BitPosition (ie, the link bit position) the packet needs to forward to the BIFT.
  • BitString bit string
  • Node 502 Checking the status of these BitPositions, that is, UP or DOWN, respectively;
  • Node 503 If the BitPosition state is DOWN, the BTAFT is searched by the BitPosition (the link bit position), and the BitString field of the BIER header is updated according to the Add BitMask and the Reset BitMask of the corresponding entry. P field is set; if the state is UP, then the node 506;
  • the node 504 is configured to: according to the BIFT-id in the BIER header, find the corresponding BRFT, and forward the packet according to the BRFT entry.
  • Node 505 If it is required to go to the forwarding process of the BIFT table, the node 506: otherwise, the forwarding process on the BFR ends;
  • Node 506 According to the original BIER forwarding process, the BIFT forwarding is searched according to the BitString of the message.
  • the search for the BRFT table is performed by the following steps: performing bit-by-bit copy forwarding according to the bit string of the BIER packet header, and checking the contents of the BRFT entry one by one to detect whether the current entry of the BRFT satisfies the lower guard ring. If the condition of the lower guard ring is met, the new field in the BIER message header is set to clear, the BIER message is copied, and the BIFT is forwarded. If the condition of the lower guard ring is not met, the BIER is directly copied. The packet is forwarded from the neighboring port corresponding to the current entry of the BRFT.
  • the forwarding process of checking the BRFT table is shown in Figure 9, which is described as follows:
  • Node 601 Check the BRFT entry one by one, check whether the entry corresponds to whether the Bit is set in the message BitString, if set, transfer to the node 602, if not set, return to the node 601, and continue to process the next entry;
  • Node 602 Check whether the content of the entry meets the condition C2, if the condition C2 is not met, the node 603 is transferred, otherwise the node 604 is transferred;
  • Node 604 copying an original message, clearing the B flag header P flag, and the copy message is transferred to the BIFT entry forwarding process; at the same time, modifying the original packet BitString (clearing the entry corresponding to the Bit bit), and then transferring Node 605;
  • Node 605 returning the node 601 with the original message, and continuing the processing of the next entry;
  • Node 606 All the entries are found, and the process ends.
  • At least one of the following conditions must be met: 1.
  • the status of the entry in the BRFT is DOWN; 2.
  • the position of the DNR in the BRFT is F.
  • this embodiment proposes a system 100 for network fault protection in BIER-TE.
  • the system 100 includes a BIER-TE controller 110 and a BIER forwarding router 120.
  • the BIER-TE controller 110 is mainly configured to allocate a link bit position and a guard ring bit position for each forwarding link of the ring topology, and the direction of the link bit position is opposite to the direction of the guard ring bit position, and the new A BIER ring forwarding table BRFT is added, and the BRFT is configured to store the contiguous forwarding entry related to forwarding in the direction of the protection ring bit position, and deliver the BIER packet forwarding related entry to the BIER forwarding through the southbound interface. router.
  • the BIER-TE controller 110 mainly includes the following modules:
  • a PCE module 111 configured to calculate a guard ring path of each forwarding link, and determine a guard ring bit position corresponding to the guard ring path, where the specific path calculation method and the guard ring bit position determining method are not the contents of the present disclosure Do not introduce too much.
  • the ring BP resource allocation module 112 is configured to allocate a guard ring bit position for each forwarding link and confirm whether the guard ring bit position can be shared. For details, refer to the subsequent embodiments.
  • the BRFT entry generation/integration module 113 is configured to generate an initial BRFT table according to the allocation of the guard ring bit positions, and integrate the C-BM information of the BRFT table according to the BRFT integration method, as described in detail. Subsequent embodiments.
  • the protection relationship management module 114 is configured to manage a correspondence between a link bit position of each forwarding link and a guard ring bit position.
  • the entry is sent to the BIER forwarding router 120 by using the southbound interface to forward the BIER packet forwarding related entry.
  • the BIER forwarding router 120 is configured to receive the BIER packet forwarding related entry sent by the BIER-TE controller 110 through the southbound interface, and if the BIER packet is forwarded along the ring topology, If the downstream adjacency of the ring topology fails, the content of the BIER-TE adjacency fast rerouting table BTAFT is searched for, and the correspondence between the link bit position of the faulty forwarding link and the guard ring bit position is found, and the BRFT is combined. The contents of the entry forward the BIER message along the direction of the guard ring bit position to the opposite fault point.
  • the BIER forwarding router 120 mainly includes the following modules:
  • the entry configuration module 121 is configured to receive, by the southbound interface, a BIER packet sent by the BIER-TE controller 110, such as a BRFT, BTAFT, BIFT, and the like.
  • the packet encapsulation module 122 is configured to encapsulate the BIER message, and modify the bit string content of the BIER message and set the new field in the BIER packet header.
  • the encapsulated BIER message includes: After the fault is detected by the fast detection technology, the BIER packet header part string is modified, and the P flag is set; when the BRFT table is checked for forwarding, the original message bit string is modified; when the lower guard ring condition C2 is satisfied, it is required The message header P field is set to clear (see the subsequent embodiment for details).
  • the message parsing module 123 is configured to additionally parse whether the new field of the BIER message header is set.
  • the message sending/receiving module 124 is configured to send and receive the BIER message; after processing by the BIER message forwarding module and the message encapsulating module, the BIER message is sent to the downstream device; and the BIER sent upstream is received. The message is handed over to other modules for further processing.
  • the BIER-TE protection forwarding module 125 is configured to determine, according to the setting condition of the newly added field in the BIER packet header, whether the BIER message is along the link bit position or along the protection ring bit position. Forward direction; according to the P flag setting in the BIER message header, check different tables for forwarding, P flag is set, check BRFT first, then check BIFT if necessary, P flag is not set, it is the original check BIFT forwarding process.
  • the BRFT forwarding module 126 is configured to perform bit-by-bit copy forwarding according to the newly added field of the BIER packet header and the content of the BRFT entry; and perform bit-by-bit copy forwarding according to the newly added field in the BIER packet header. Need to combine C-BM, table status (Status) and so on.
  • the fast detection module 127 is configured to perform connectivity detection on each forwarding link in the ring topology by using a fast detection technology. When a fault is detected or the fault is recovered, the status of the associated adjacency entry is also followed. Changes, which are outside the scope of this disclosure, are not described too much.
  • the embodiment provides a storage medium for computer readable storage, the storage medium storing one or more programs, the one or more programs being executable by one or more processors to implement the foregoing embodiment The steps of the method for network fault protection in BIER-TE.
  • This embodiment further describes the implementation process of the protection ring bit position allocation according to the actual situation.
  • the single ring topology shown in FIG. 11 is taken as an example to introduce the allocation process of the protection ring bit position (BitPosition) in this scenario:
  • Link A-->C is a non-special link special-interconnected-link, and the ring where P AC and P AD are located is the same one, which is A-->B-->D-->C--> A, clockwise;
  • BitPosition 5 ie, guard ring bit position
  • DNR is set to T.
  • the BRFT entries on the A node are shown in Figure 25. The other nodes are similar.
  • the dual-ring topology shown in Figure 12 is taken as an example.
  • the link A-->B is located in the BitPosition.
  • Bit position configure FRR, according to the guard ring bit position allocation process, assign two guard rings BitPosition1 and 2 (represented by small ring lines and large elliptical ring lines in Figure 12), and protected BitPosition (ie chain) on each node Figure 26 shows the related BRFT entries for the link bit position where the path A-->B is located.
  • This embodiment further describes the formation process of the BTAFT entry in the actual situation.
  • the dual-ring topology shown in Figure 13 is used as an example.
  • the FRR is configured for the BitPosition1 where the link B-->E is located.
  • For the allocation process of the ring bit position assign two guard rings BitPosition 3 and 4 (BitPosition 3 in Figure 13 is the left closed ring, counterclockwise, BitPosition 4 is the right non-closed ring, clockwise), for example, BTAFT entry formation process:
  • Add BitMask is a bit string composed of two loop BitPosition, which is 1100;
  • Reset BitMask is a bit string consisting of BitPosition1 and E-->F on BitPosition2 (DS-NH is E node, DNR is marked as F on F node), which is 0011;
  • This embodiment provides a method for distinguishing whether a BIER packet is forwarded in a working path (ie, forwarding in a direction along a bit position of the link) or a guard ring path (ie, forwarding in a direction along a bit position of the guard ring).
  • This example further describes the fault protection process in a single-ring topology scenario, as shown in Figure 14.
  • the single-ring topology is shown in Figure 14.
  • the related BitPosition is shown in the figure.
  • the Bit-Position1 on the A-->C link is configured with TE-FRR protection.
  • the guard ring of the BitPosition1 is a clockwise ring, and is assigned a BitPosition7;
  • BFIR is A node
  • BFER is C
  • D node under normal network conditions, the traffic path is A-->C, A-->B-->D, as shown in Figure 14. Marked with an arrow with a straight line.
  • Node A receives the BIER message and searches for BIFT according to the message BitString (00110111).
  • the matched BP is 1 and 2;
  • Node B receives two BIER messages, and the P field in a packet is not set.
  • the original forwarding process is carried out (the packet is forwarded to the D node and the BIER header is stripped);
  • the P field is set (the packet is in the guard ring path), and the A node checks the BRFT entry, and the entry corresponding to BP7 matches.
  • the C node receives a BIER message, the P field is set, and the BRFT entry is checked. The entry corresponding to BP7 matches. Because the A-->C link is faulty, the associated BP7 state is DOWN, and the condition is met. C2;
  • the multicast service traffic path is shown in Figure 15 with the arrow line bar, the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • Node D receives two BIER messages, the P field is not set in one message, the original forwarding process is taken, and the BIER header is stripped; in the other packet, the P field is set (the packet is protected) Ring path), with the A node, check the BRFT entry, the entry corresponding to BP7 matches, because the node C is faulty, its state is DOWN, and the condition C2 is satisfied;
  • the multicast service traffic path is shown in Figure 16 with an arrow and a straight line bar.
  • the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • This example further illustrates the fault protection process in the dual-ring topology scenario 1, as shown in Figure 17, in the dual-ring topology.
  • BP-2 special-interconnected-link
  • the TE-FRR protection is configured, and according to the disclosed scheme, guard rings BP8 and 9 are assigned thereto (BP8 in the figure 17 is the left closed loop, counterclockwise, BP9 is the right non-closed loop, clockwise)
  • BFIR is the B node and BFER is the A, D, and F nodes.
  • BFER is the A, D, and F nodes.
  • the service traffic path is B-->A, B-->E-->D, B-- >E-->F, see Figure 17 with the arrow line mark.
  • Node B receives the BIER message and searches for BIFT according to the message BitString (01111111).
  • the matched BP is 1 and 2;
  • the E-node receives the BIER packet, the P field is set, and the BRFT entry is checked. The entry corresponding to BP8 matches. The B-->E link is faulty, and its associated BP8 state is DOWN, which satisfies the condition C2.
  • the F node receives the BIER message, the P field is set, and the BRFT entry is checked.
  • the entry corresponding to BP9 matches, because the DNR of the entry is set to F, and the condition C2 is satisfied.
  • the multicast service traffic path is marked with an arrow with a straight line as shown in Figure 18.
  • the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • the multicast service traffic path is marked with an arrow with a straight line as shown in Figure 19.
  • the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • This example further illustrates the fault protection process in the dual-ring topology scenario 2, as shown in Figure 20, in the dual-ring topology.
  • BP1 on the link A-->B is configured with TE-FRR protection.
  • guard rings BP7 and 8 are assigned thereto (BP8 in FIG. 20 is a small ring line, counterclockwise, BP9 is a large elliptical ring line, counterclockwise)
  • BFIR is the A node and BFER is the C and F nodes.
  • service traffic path is A-->B-->C, A-->B-->E-- >F, see Figure 20 with the arrow line mark.
  • Node A receives the BIER message and searches for BIFT according to the message BitString (00111111), and the matching BP is 1;
  • Node B receives the BIER packet, the P field is set, and the BRFT entry is checked. The entries corresponding to BP7 and BP8 match. The A-->B link is faulty, and its associated state is DOWN, which satisfies the condition C2.
  • the multicast service traffic path is shown in Figure 21 with an arrow and a straight line bar.
  • the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • Node E receives the BIER packet, the P field is set (the packet is in the guard ring path), and the BRFT entry is checked. The entry corresponding to BP7 matches. The node B is faulty and its state is DOWN, which satisfies the condition C2.
  • Node C receives the BIER packet, the P field is set (the packet is taken out of the protection ring path), and the BRFT entry is checked. The entry corresponding to BP8 matches. Because node B is faulty, its state is DOWN, which satisfies condition C2.
  • the multicast service traffic path is shown in Figure 22 with the arrow line bar, the solid line indicates that it is not affected by the fault, and the dotted line indicates the guard ring.
  • the BIER-TE network fault protection solution proposed by the embodiment of the present disclosure is based on the network topology and does not care about the specific multicast service. Therefore, in some scenarios, the problem that individual nodes may receive dual traffic may occur.
  • Several problems proposed by Eckert-Bier-Te-Frr also have such problems, and how to solve this problem is not within the scope of the present disclosure.
  • a method, system, and storage medium for network fault protection in a BIER-TE which allocates a guard ring bit position for each forwarding link of a ring topology, wherein a direction of a guard ring bit position and a corresponding forwarding chain The working path of the road is reversed.
  • a BIER ring forwarding table BRFT is added to store the adjacent forwarding entries related to forwarding in the direction of the protection ring bit position. In this way, when the BIER packet is forwarded along the working path, if the BIER forwarding router BFR detects that the downstream neighbor of a forwarding link fails, the content of the BIER-TE adjacency fast rerouting table BTAFT is searched.
  • the BIER packet can be forwarded to bypass the fault forwarding link, ensuring that the BIER packet is successfully forwarded to each normal node in the ring topology.
  • the present disclosure relates to the field of network technology.
  • the embodiment provided by the present disclosure can bypass the fault forwarding link when the BIER packet is forwarded, and ensure that the BIER packet is successfully forwarded to each normal node of the ring topology.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Small-Scale Networks (AREA)

Abstract

本公开公开一种网络故障保护的方法、系统和存储介质，属于网络技术领域。该方法包括：为环形拓扑的每一转发链路分配与工作路径方向相反的保护环比特位置；新增BRFT，用于存放沿保护环比特位置的方向进行转发相关的邻接转发表项；当BIER报文沿着工作路径进行转发时，若BFR检测到下游邻接发生故障，则查找BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合BRFT的表项内容将BIER报文沿着保护环比特位置的方向转发至对端故障点。本公开实施例通过保护环比特位置及新增BRFT，可在BIER报文转发时，绕过故障转发链路，确保BIER报文成功转发至环形拓扑的每一正常节点。

Description

一种网络故障保护的方法、系统和存储介质 技术领域
本公开涉及网络技术领域，尤其涉及一种基于流量工程的位索引显式复制(Bit Index Explicit Replication Traffic Engineering，BIER-TE)中网络故障保护的方法、系统和存储介质。
背景技术
在Draft-Eckert-Bier-Te-Arch文稿中提出的BIER-TE是基于流量工程的BIER转发架构，其在BIER的基础上引入BIER-TE控制器层，并通过控制器下发转发表，同时使用路径计算单元(Path Computation Element，PCE)按需求规划最优路径，通过显式的逐跳方式转发报文，使得网络流量控制更加灵活。而在此基础上，另一文稿Draft-Eckert-Bier-Te-Frr中进一步提供了BIER-TE网络故障保护的三种措施，包括点到点隧道(Point-to-Point Tunneling，PPT)，包头修改(Header Modification,HM)和BIER-in-BIER封装(BIER-in-BIER Encapsulation，BBE)，这三种故障保护方案虽各有其优点，但仍存在不足之处。
发明内容
本公开的主要目的在于提出一种网络故障保护的方法、系统和存储介质，旨在通过保护环比特位置及新增BRFT，可在BIER报文转发时，绕过故障转发链路，确保BIER报文成功转发至环形拓扑的每一正常节点。
为实现上述目的，本公开实施例提供了一种网络故障保护的方法，所述方法包括以下步骤：为环形拓扑的每一转发链路分配保护环比特位置，所述保护环比特位置的方向与相应的所述转发链路的工作路径相反设置；新增一个BIER环转发表(BIER Ring Forwarding Table，BRFT)，所述BRFT用于存放沿所述保护环比特位置的方向进行转发相关的邻接转发表项；当BIER报文沿着所述工作路径进行转发时，若BIER转发路由器(BIER Forwarding Router，BFR)检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表(BIER-TE Adjacency FRR Table，BTAFT)的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点。
为实现上述目的，本公开实施例还提出了一种网络故障保护的系统，所述系统包括：BIER-TE控制器，用于为环形拓扑的每一转发链路分配保护环比特位置，所述保护环比特位置的方向与相应的所述转发链路的工作路径相反设置，新增一个BIER环 转发表BRFT，所述BRFT用于存放沿所述保护环比特位置的方向进行转发相关的邻接转发表项，并通过南向接口将所述BIER报文转发相关的表项下发至BIER转发路由器；BIER转发路由器，用于通过南向接口接收所述BIER-TE控制器发送过来的BIER报文转发相关的表项，并在BIER报文沿着所述工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点。
为实现上述目的，本公开提供了一种存储介质，用于计算机可读存储，所述存储介质存储有一个或者多个程序，所述一个或者多个程序可被一个或者多个处理器执行，以实现前述方法的步骤。
本公开提出的BIER-TE中网络故障保护的方法、系统和存储介质，其为环形拓扑的每一转发链路分配保护环比特位置，其中，保护环比特位置的方向与相应的转发链路的工作路径相反设置。同时，新增一个BIER环转发表BRFT，以用于存放沿保护环比特位置的方向进行转发相关的邻接转发表项。这样一来，当BIER报文沿着该工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合该BRFT的表项内容将该BIER报文沿着该保护环比特位置的方向转发至对端故障点。如此一来，便可在BIER报文转发时，绕过故障转发链路，确保BIER报文成功转发至环形拓扑的每一正常节点。
附图说明
图1是本公开实施例一提供的网络故障保护的方法的流程图。
图2是本公开环网保护概述图。
图3是本公开BIER-TE故障保护控制面总流程图。
图4是本公开BIER-TE保护环BitPosition分配以及BRFT表项设置流程图。
图5是本公开双环双节点拓扑图。
图6是本公开BRFT表项整合、下发流程图。
图7是本公开BTAFT表项形成流程图。
图8是本公开BIER-TE FRR转发流程图。
图9是本公开BRFT转发流程图。
图10是本公开实施例二提供的网络故障保护的系统的结构框图。
图11是本公开实施例四单环拓扑的结构示意图。
图12是本公开实施例五双环拓扑的结构示意图。
图13是本公开实施例六双环拓扑的结构示意图。
图14是本公开实施例八单环拓扑的结构示意图。
图15是图14所示单环拓扑链路故障时的组播业务流量路径示意图。
图16是图14所示单环拓扑节点故障时的组播业务流量路径示意图。
图17是本公开实施例九双环拓扑的结构示意图。
图18是图17所示双环拓扑链路故障时的组播业务流量路径示意图。
图19是图17所示双环拓扑节点故障时的组播业务流量路径示意图。
图20是本公开实施例九双环拓扑的结构示意图。
图21是图20所示双环拓扑链路故障时的组播业务流量路径示意图。
图22是图20所示双环拓扑节点故障时的组播业务流量路径示意图。
本公开目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。
图23是根据实施例一的BRFT表简例。
图24是根据实施例一的BTAFT表简例。
图25是根据实施例四的A节点上的BRFT表项。
图26是根据实施例五的整合前各节点上的BRFT表项。
图27是根据实施例五的整合后各节点上的BRFT表项。
图28是根据实施例六的B节点上的BTAFT表项。
图29是根据实施例七的BIER报文头简例。
具体实施方式
应当理解，此处所描述的具体实施例仅仅用以解释本公开，并不用于限定本公开。
在后续的描述中，使用用于表示元件的诸如“模块”、“部件”或“单元”的后缀仅为了有利于本公开的说明，其本身没有特有的意义。因此，“模块”、“部件”或“单元”可以混合地使用。
实施例一
如图1所示，本实施例提供了一种BIER-TE中网络故障保护的方法，所述方法包括以下步骤：
步骤S110：为环形拓扑的每一转发链路分配保护环比特位置，该保护环比特位置的方向与相应的转发链路的工作路径相反设置。
本实施例使用环网保护思想对BIER-TE(Bit Index Explicit Replication Traffic Engineering，基于流量工程的位索引显式复制)中网络故障进行保护。针对BIER转发路由器(BIER Forwarding Router，BFR)的环形拓扑，如图2所示，其为该环形拓扑的每一转发链路分配链路比特位置(BitPosition，BP)与保护环比特位置，其中， 链路比特位置的方向即为相应转发链路的工作路径，保护环比特位置的方向与链路比特位置的方向呈相反设置，即保护环比特位置的方向与相应的转发链路的工作路径相反设置。这样一来，当链路比特位置的方向为顺时针方向时，保护环比特位置的方向为逆时针方向，而当链路比特位置的方向为逆时针方向时，保护环比特位置的方向则为顺时针方向。如图2所示，对于A到B方向上的转发链路而言，其链路比特位置(BitPosition，BP)为顺时针方向，用与其相反方向的保护环比特位置(图中大圆环线条所示方向)进行保护，即通过逆时针方向的保护环比特位置进行保护；而对于A到C方向上的转发链路而言，其链路比特位置(BitPosition，BP)为逆时针方向，用与其相反方向的保护环比特位置(图中小圆环线条所示方向)进行保护，即通过顺时针方向的保护环比特位置(图中)进行保护。保护环比特位置与被保护转发链路的链路比特位置需属于同一个<SD:BSL:SI>集。
保护环比特位置的分配和共享具体应遵循以下规则：如果是环形拓扑被保护的转发链路是特殊相交链路(Special Interconnected-link)，则对应分配的保护环比特位置不能被共享，除此之外的链路，其对应分配的保护环比特位置可以共享。
步骤S120：新增一个BIER环转发表BRFT，该BRFT用于存放沿该保护环比特位置的方向进行转发相关的邻接转发表项。
新增一个BIER环转发表(BIER Ring Forwarding Table，BRFT)，其主要用来存放沿该保护环比特位置的方向进行转发相关的邻接转发表项，当环形拓扑的下游邻接发生故障(包括链路故障和链路故障)时，BIER报文需要查找此表以在保护环比特位置的方向上进行数据转发。
如图23所示，该BRFT表中至少包含以下几项：
位索引Index信息：同BIER-TE的BIFT(Bit Index Forwarding Table，位索引转发表)，一个BIFT-id对应一张BRFT表，位索引Index信息表示该表中BitPosition对应的bit索引；
邻接Adjacencies信息：同BIER-TE的BIFT(Bit Index Forwarding Table，位索引转发表)，表示邻接相关的信息，如标签、端口等信息；
标记DNR(Do Not Reset)信息：对于forward_connected的类型的邻接，该字段表示是否需要清除其对应bit位，T表示不清除，F表示清除；
转发时报文需要清除的位掩码C-BM(Clear-BitMask)信息：类似F-BM，在数据转发时按照转发规则，位字串(BitString)与C-BM作用得到新的位字串(BitString)；
表项状态Status信息：与检测相关的表项状态，链路的快速检测状态与相关表项关联。
该BRFT的表项内容具体可通过以下步骤形成：根据保护环比特位置的分配过程，对该保护环比特位置所经过的每一节点进行BRFT表配置。进一步地，根据被保护的转发链路的链路类型(分特殊相交链路(Special Interconnected-link)和普通链路)， 找出闭合环和非闭合环，对于非闭合环，在环上的DS-NNHs链路的标记DNR(Do Not Reset)信息置F，其余链路的标记DNR(Do Not Reset)信息置T；对于闭合环，环上所有链路的标记DNR(Do Not Reset)信息全部为T(闭合环)，转发时报文需要清除的位掩码C-BM信息设置为保护环比特位置对应的位字串。
步骤S130：当BIER报文沿着该工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合该BRFT的表项内容将该BIER报文沿着该保护环比特位置的方向转发至对端故障点。
环形拓扑的每一条转发链路使用快速检测技术(如BFD或者二层链路快速检测方法)检测其连通性，并与其上配置的BRFT、BIFT中BIER-TE Adjacency(邻接)进行状态关联，由于这不在本公开范围内，故在此不做过多描述。
另外，在本步骤前，还需通过南向接口(NETCONF/RESTCONF/PCEP/BGP-LS等)将该BIER报文转发相关的表项(如BIFT、BRFT、BTAFT表等)下发至BIER转发路由器BFR，以便该BIER报文在该BIER转发路由器上进行转发。
由于本实施例的BIER报文在正常情况下沿工作路径(即链路比特位置的方向)进行转发，有故障时沿保护环路径(即保护环比特位置的方向)进行转发。为对之进行区分及便于后续转发流程的处理，可在本步骤之前，扩展该BIER报文头部，通过新增字段来区分该BIER报文是沿着该工作路径(即链路比特位置的方向)还是沿着该保护环比特位置进行转发。如在该BIER报文头部增加一个P字段，用于区分该BIER报文是沿着该工作路径还是沿着该保护环比特位置的方向进行转发，如果该BIER报文沿着该保护环比特位置的方向进行转发，则将该P字段标志位置位，如果该BIER报文沿着该工作路径或者需要脱离保护环比特位置的方向，则清除该P字段标志位。新增P字段可以通过使用BIER报文头部保留字段的一位或者多位来实现，但也不限其它方式。
本实施例同样会使用到BIER-TE邻接快速重路由表(BIER-TE Adjacency FRR Table，BTAFT)，表项内容同Draft-Eckert-Bier-Te-Frr文稿中描述，如图24所示。
这样一来，当BIER报文沿着该工作路径进行转发时，若BIER转发路由器(BIER Forwarding Router，BFR)检测到某一转发链路的下游邻接发生故障(包括链路故障或者链路故障)，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，使用BTAFT对应表项的Add BitMask(添加位掩码)和Reset BitMask(重置位掩码)修改该BIER报文的位字串内容，用故障转发链路的保护环比特位置替换故障转发链路的链路比特位置，同时将该BIER报文头部的新增字段(即P字段)进行置位操作。然后，结合该BRFT的表项内容将该BIER报文沿着保护环路径(即保护环比特位置的方向)转发至对端故障 点。当满足下环条件，则该BIER报文不再继续沿着保护环路径进行转发，此时，将该BIER报文从保护环路径(即保护环比特位置的方向)转到正常工作路径(即链路比特位置的方向)上，如此便可通过上述方法绕过故障点，后续转发按照原有路径即可。
在BIER-TE架构中，Bier-TE控制器(Controller)主要用来进行控制面信息的处理，其通过南向接口(NETCONF/RESTCONF/PCEP/BGP-LS等)向BIER转发路由器BFR下发相应配置信息(如BIFT、BRFT、BTAFT表等)。以下流程全部由Bier-TE Controller完成，控制面总流程如图3所示，介绍如下：
节点101：选择被保护BitPosition(即被保护转发链路的链路比特位置)，分配保护环BitPosition(即保护环比特位置)，设置BRFT表项内容。
节点102：BRFT表项整合，并通过南向接口下发至BIER转发路由器。
节点103：形成BTAFT表项，并通过南向接口下发至BIER转发路由器。
其中，BIER-TE保护环BitPosition(即保护环比特位置)分配以及BRFT表项设置流程如图4所示，介绍如下：
节点201：在BFRx(表示BIER转发路由器某一保护点)上需要保护的BitPosition(即链路比特位置)，称为X <SD:BSL:SI>，分别计算出BFR到X <SD:BSL:SI>邻接的对端节点(downstream next-hop，DS-NH)和下游下下一跳节点(downstream next next-hops，DS-NNHs)的路径，分别称为P x-NH，P x-NNH1，P x-NNH2……；然后转步骤(2)；其中P x-NH路径不能经过X <SD:BSL:SI>所属链路；P x-NNH1，P x-NNH2……路径不能经过X <SD:BSL:SI>所属链路以及DS-NH与对应DS-NNH链路的链路；上述路径可以看做是沿着某个方向(逆时针或者顺时针)的环上的一个片段；
节点202：判断X <SD:BSL:SI>所在链路是否是特殊相交链路(Special Interconnected-link)，如果是，转节点203，否则转步骤节点204；
节点203：对路径P x-NH，P x-NNH1，P x-NNH2……，依次判断是否已经为该路径所在环R (d，x-NH)或者R (d，x-NNH1)，R (d，x-NNH2)……(d表示方向，c为顺时针，a为逆时针)分配对应<SD:BSL:SI>的BitPosition，R (d，x-NH)环上各链路配置相应BRFT表项，DNR标记位置T；环R (d，x-NNH1)，R (d，x-NNH2)……中至少会有一个环和R (d，x-NH)相同，筛选出与R (d，x-NH)不相同的环R (d，x-NNH)，在其对应P x-NNH经过的节点配置BRFT表项，其中DS-NNHs节点上DNR标记位置F，其余节点置T；C-BM设置为环BP(即保护环比特位置)对应的BitString(邻接信息同BIFT，无特殊处理，不再复述)，流程结束；
节点204：对路径P x-NH，P x-NNH1，P x-NNH2……，依次判断是否已经为该路径所在环R d-NH或者R (d，x-NNH1)，R (d，x-NNH2)……(d表示方向，c为顺时针，a为逆时针)分配对应<SD:BSL:SI>的BitPosition，如果该方向已分配BitPosition，则流程结束；否则转步骤节点205；
节点205：为上述环R (d，x-NH)，R (d，x-NNH1)，R (d，x-NNH2)……分配相应的BitPosition (环R (d，x-NNH1)，R (d，x-NNH2)……中至少会有一个环和R (d，x-NH)相同，只需分配一个BitPosition)，环R (d，x-NH)，R (d，x-NNH1)，R (d，x-NNH2)……上各链路配置相应BRFT表项，其中DNR标记位全部置T(即全部是闭合环)，C-BM设置为环BP(即保护环比特位置)对应的BitString(邻接信息同BIFT，无特殊处理，不再复述)，流程结束。
上述流程中，Special Interconnected-link是本公开提出的术语，两个环相交的链路，如果其DS-NNH节点数大于等于2，那么该链路即为Special Interconnected-link。在本公开中，Special Interconnected-link的TE-FRR保护有别于一般链路，其链路比特位置(BitPosition)的某个或者某几个保护环比特位置不共享(保护环为非闭合环，对应表项标记DNR信息有F置位)，而其它BitPosition的保护环为闭合环(环上所有链路对应表项标记DNR信息全部为T)，可以共享。存在Special Interconnected-link的其中一个典型拓扑为双环双节点拓扑，即如图5所示，图中链路L为Special Interconnected-link。
因本公开提出的保护方案与拓扑相关，有时需要用到多个保护环，在某些BFR(多个环经过的节点)上对应的BRFT表项就会有多条，在报文转发过程中需要选择合适的条目并按照其表项内容进行转发。BRFT表项整合、下发流程如图6所示，介绍如下：
节点301：接上述保护环BitPosition分配和BRFT表项配置流程，BRFT项中邻接信息，DNR标记，C-BM均已配置；
节点302：依次判断每个节点上被保护BitPosition(即链路比特位置)关联的BRFT表项是否满足条件C1，满足转节点303，否则转步骤节点304；
节点303：根据公式1计算出这些表项的C-BM；
节点304：本节点上BRFT表项各字段内容全部更新和确定后，通过南向接口向BIER转发路由器下发表项；
节点305：转步骤节点302，进入下一节点处理流程；
节点306：所有节点的BRFT表项全部下发完毕，流程结束。
上述流程中，条件C1内容如下：
需同时满足以下2条：
1、某BFR链路上DNR标记为T的表项条目数大于1；
2、该BFR链路为非PLR(Point of Local-Repair，本地修改点)，或者相关表项中邻接接口相同。
用index x、y、z表示某BFR上被保护BitPosition(即链路比特位置)相关的BRFT表项索引，C-BM index表示该表项的C-BM，假设该BRF上x、y、z表项满足条件C1，则公式1：C-BM x/y/z＝C-BM x|C-BM y|C-BM z。
接上面环BitPosition(即保护环比特位置)分配流程，BTAFT表项形成流程如图7所示，介绍如下：
节点401：在上述计算保护环路径、分配保护环BitPosition，以及下发BRFT表 项流程之后，分别计算BTAFT表项中Add BitMask和Reset BitMask值；
节点402：Add BitMask为上述流程中计算出的一个或者多个保护环BitPosition组成的位字串(BitString)；
节点403：Reset BitMask为被保护的BitPosition(即被保护转发链路的链路比特位置)以及DS-NH到DNR标记置F的DS-NNHs的链路对应的BitPosition组成的Bit位字串(BitString)；
节点404：通过南向接口向BFRx下发BTAFT表项，FRR adjacency表示被保护的BitPosition，用计算得到的Add BitMask和Reset BitMask填充对应表项。
BIER报文转发时，根据该BIER报文头部的新增字段是否置位，来决定是查找原来的位索引转发表BIFT还是查找新增的所述BRFT进行转发。当BIER-TE中网络故障发生时(包括链路故障或者链路故障)，其关联的BitPosition(即链路比特位置)状态为DOWN，为了实现快速故障保护，需要对原有BIER转发流程稍做修改，流程如图8所示，具体介绍如下：
节点501：BFR收到BIER报文，结合报文中BitString(位字串)查找BIFT决定报文需要转发给哪些下游BitPosition(即链路比特位置)；
节点502：分别检查这些BitPosition(即链路比特位置)状态，是UP还是DOWN；
节点503：若BitPosition(即链路比特位置)状态为DOWN，通过该BitPosition(即链路比特位置)查找BTAFT，根据对应表项的Add BitMask和Reset BitMask更新BIER报文头的BitString字段，并将P字段置位；若状态为UP，则转节点506；
节点504：因报文P字段置位，根据BIER报文头中的BIFT-id查找对应BRFT，按照BRFT表项进行转发；
节点505：如果需要转到查BIFT表的转发流程，则转节点506：，否则该BFR上的转发流程结束；
节点506：按照原有BIER转发流程，根据报文的BitString按位查找BIFT转发。
其中，查找BRFT表进行转发，通过以下步骤来完成：根据BIER报文头部的位字串进行按位复制转发，逐条查看BRFT的表项内容，以检测BRFT的当前表项是否满足下保护环的条件；若满足下保护环的条件，则将BIER报文头部的新增字段置位清除，复制BIER报文，并查找BIFT进行转发；若不满足下保护环的条件，则直接复制BIER报文，并从BRFT的当前表项对应的邻接端口转发出去。查BRFT表的转发流程如图9所示，介绍如下：
节点601：逐条查看BRFT表项，检查该表项对应Bit在报文BitString中是否置位，如果置位，转节点602，如果未置位，则返回节点601，继续下一条表项处理；
节点602：查看表项内容是否满足条件C2，若不满足条件C2，转节点603，否则转节点604；
节点603：复制一份原始报文，然后从该BRFT表项对应邻接端口转发出去；同 时，修改原始报文BitString(BitString&＝～C-BM)，然后转节点605；
节点604：复制一份原始报文，将BIER报文头P标记位清除，该复制报文转到BIFT表项转发流程；同时，修改原始报文BitString(清除表项对应Bit位)，然后转节点605；
节点605：带原报文返回节点601，继续下一条表项处理；
节点606：表项全部查找完毕，流程结束。
上述流程中判断条件C2内容如下：
需满足以下条件中至少一条：1、BRFT中该表项状态为DOWN；2、BRFT中该表项DNR标记位置F。
实施例二
如图10所示，本实施例提出了一种BIER-TE中网络故障保护的系统100，该系统100包括BIER-TE控制器110及BIER转发路由器120。
其中，BIER-TE控制器110主要用于为环形拓扑的每一转发链路分配链路比特位置与保护环比特位置，该链路比特位置的方向与该保护环比特位置的方向相反设置，新增一个BIER环转发表BRFT，该BRFT用于存放沿该保护环比特位置的方向进行转发相关的邻接转发表项，并通过南向接口将该BIER报文转发相关的表项下发至BIER转发路由器。
该BIER-TE控制器110主要包括以下模块：
PCE模块111，其用于计算每一转发链路的保护环路径，以及确定该保护环路径所对应的保护环比特位置，具体路径计算方法以及保护环比特位置确定方法不是本公开需要关注的内容，不做过多介绍。
环BP资源分配模块112，其用于为每一转发链路分配保护环比特位置，以及确认该保护环比特位置是否可以被共享，具体情况可详见后续实施例。
BRFT表项生成/整合模块113，其用于根据所述保护环比特位置的分配情况生成初始BRFT表，并按照BRFT整合方法对所述BRFT表的C-BM信息进行整合，具体情况可详见后续实施例。
保护关系管理模块114，其用于管理每一转发链路的链路比特位置与保护环比特位置的对应关系。
表项下发模块115，其用于通过南向接口将该BIER报文转发相关的表项下发至BIER转发路由器120。
BIER转发路由器120主要用于通过南向接口接收该BIER-TE控制器110发送过来的BIER报文转发相关的表项，并在该BIER报文沿着该环形拓扑进行转发时，若检测到该环形拓扑的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合该BRFT的表项内容将所述BIER报文沿着该保护环比特位置的方向转发至对端故障 点。
该BIER转发路由器120主要包括以下几个模块：
表项配置模块121，其用于通过南向接口接收该BIER-TE控制器110发送过来的BIER报文转发相关的表项，如BRFT、BTAFT、BIFT等表。
报文封装模块122，其用于该BIER报文的封装，包括修改该BIER报文的位字串内容以及对该BIER报文头部的新增字段进行置位操作；封装BIER报文包括：当通过快速检测技术检测到故障后，修改BIER报文头部位字串，P标记置位；查BRFT表进行转发时，修改原始报文位字串；当满足下保护环条件C2时，需要将报文头部P字段置位清除(详情可见后续实施例)。
报文解析模块123，其用于额外解析该BIER报文头部的新增字段是否置位。
报文发送/接收模块124，其用于该BIER报文的发送与接收操作；通过BIER报文转发模块和报文封装模块的处理后，将BIER报文发送给下游设备；接收上游发送的BIER报文，交由其他模块做进一步处理。
BIER-TE保护转发模块125，其用于根据该BIER报文头部的新增字段的置位情况，确定该BIER报文是沿着该链路比特位置的方向还是沿着该保护环比特位置的方向进行转发；根据BIER报文头部中P标记置位情况，查不同表进行转发，P标记置位，先查BRFT，必要时再查BIFT，P标记不置位，则是原有的查BIFT的转发流程。
BRFT转发模块126，其用于根据该BIER报文头部的新增字段并结合所述BRFT的表项内容来进行按位复制转发；根据BIER报文头部新增字段进行按位复制转发，需要结合C-BM，表项状态(Status)等内容。
快速检测模块127，其用于通过快速检测技术手段，对该环形拓扑中的每一转发链路进行连通性检测，当检测到故障或者故障恢复，则与其关联的邻接表项的状态也随之改变，这不在本公开范围内，不做过多描述。
实施例三
本实施例提供了一种存储介质，用于计算机可读存储，该存储介质存储有一个或者多个程序，该一个或者多个程序可被一个或者多个处理器执行，以实现前述实施例一中BIER-TE中网络故障保护的方法的步骤。
实施例四
本实施例结合实际情况进一步说明保护环比特位置分配的实施过程，具体以如图11所示的单环拓扑为例，介绍此场景下保护环比特位置(BitPosition)的分配过程：
(1)在A节点上选择A-->C链路上的BitPosition 1(即链路比特位置)进行保护，DS-NH为C节点，DS-NNH为D节点，计算出P A-C为A-->B-->D-->C，P A-D为A-->B-->D，见图11中带箭头实线条与带箭头虚线条所示；
(2)链路A-->C为非特殊链路special-interconnected-link，并且P A-C和P A-D所在环是同一个，为A-->B-->D-->C-->A，顺时针方向；
(3)上述环(顺时针方向)在对应<SD:BSL:SI>下还未分配BP，则为该环顺时针方向分配BitPosition 5(即保护环比特位置)，并在节点A、B、C、D根据拓扑分别设置BRFT表项，DNR设置为T，A节点上的BRFT表项如图25所示，其余节点与之类似。
实施例五
本实施例结合实际情况进一步说明BRFT表项的整合、形成过程，具体以如图12所示的双环拓扑为例，在该双环拓扑场景下为链路A-->B所在BitPosition(即链路比特位置)配置FRR，根据保护环比特位置分配流程，分配两个保护环BitPosition1和2(图12中分别用小圆环线条和大椭圆环线条表示)，各节点上与被保护BitPosition(即链路A-->B所在的链路比特位置)相关的BRFT表项如图26所示，
以此为例，介绍BRFT表项整合及下发流程：
(1)节点A和节点D上分别有2条BRFT条目，满足条件C1(条目数大于1，并且邻接端口相同)，则根据公式1计算出这2个表项的C-BM＝0011；
(2)节点B和节点E上分别有2条BRFT条目，满足条件C1(条目数大于1，并且为非PLR节点)，则根据公式1计算出这2个表项的C-BM＝0011；
(3)节点C和节点F上分别有1条BRFT条目，不满足条件C1，无需处理，C-BM＝0010；
(4)通过整合，各节点上的BRFT表项最终内容如图27所示，这些表项通过南向接口下发至各节点。
实施例六
本实施例结合实际情况进一步说明BTAFT表项的形成过程，具体以如图13所示的双环拓扑为例，在该双环拓扑场景下，为链路B-->E所在BitPosition1配置FRR，根据保护环比特位置的分配流程，分配两个保护环BitPosition 3和4(图13中BitPosition 3为左边闭合环，逆时针方向，BitPosition 4为右边非闭合环，顺时针方向)，以此为例，介绍BTAFT表项形成流程：
(1)Add BitMask为两个环BitPosition组成的位字串，为1100；
(2)Reset BitMask是被保护BitPosition1和E-->F上BitPosition2(DS-NH为E节点，F节点上DNR标记为F)组成的位字串，为0011；
(3)最终，B节点上形成的BTAFT表项内容如图28所示，通过南向接口向节点B下发该表项条目。
实施例七
本实施例提出一种区分BIER报文走在工作路径(即沿着该链路比特位置的方向进行转发)还是保护环路径(即沿着该保护环比特位置的方向进行转发)的方法，具体的，在BIER报文头中增加一个P字段标记位，该标记位置位表示报文走环形保护环路径；如果报文走工作路径或者需要脱离环形保护环路径，则P标志置位需清除。
如图29所示，是其中一种BIER报文头封装方式，使用保留字段Rsv的一个bit做为P标记字段。其他封装方式不再一一例举。
实施例八
本实施例结合实际情况进一步说明单环拓扑场景下的故障保护过程，如图14所示的单环拓扑，相关BitPosition见图中所示，A-->C链路上BitPosition1配置TE-FRR保护，根据本公开方案，该BitPosition1的保护环为顺时针环，为其分配了BitPosition7；
现在有一条组播业务流，BFIR为A节点，BFER为C、D节点；在网络正常情况下流量路径为A-->C，A-->B-->D，见图14所示的带箭头直线条标记。
故障场景1--链路故障：
当A-->C链路发生故障，报文转发流程如下：
(1)A节点收到BIER报文，根据报文BitString(00110111)查找BIFT，匹配的BP为1和2；
(2)因BP2表项正常，则根据表项邻接信息将复制报文转发到下游节点B(后续该报文都是按照原有的转发流程进行，不是本公开内容，不做过多描述)；而链路A-->C故障，其关联的BP1状态为Down，查BTAFT表并更新报文BitString(Add BitMask＝01000000，Reset BitMask＝00000001)，更新后的BitString＝01110100，并且报文头中P字段置位；
(3)因P字段被置位，则需要查找对应BRFT表项，A节点BRFT表中BP7对应表项匹配，不满足条件C2(即，需要继续沿保护环转发)
(4)复制一份报文，BitString不做修改，依然为01110100，转发至下游节点B；
(5)节点B(节点D同节点B)收到两份BIER报文，一份报文中P字段不置位，走原有转发流程(报文转发至D节点，剥BIER报文头)；另一份报文中P字段置位(报文走保护环路径)，同A节点，查BRFT表项，BP7对应的表项匹配，不满足条件C2，复制报文(BitString＝01110100)转发至下游节点D(节点C)；
(6)C节点收到一份BIER报文，P字段置位，查BRFT表项，BP7对应的表项匹配，因A-->C链路故障，其关联的BP7状态为DOWN，满足条件C2；
(7)复制报文，清除P字段置位(BitString＝01110100)，转到BIFT转发流程，BIFT表项中BP5对应表项匹配，因是local-decap类型，报文在C节点需要剥离BIER报文头，BIER转发流程结束。BitString中其他置位的bit位在BIFT中无匹配表项。
上述故障时，组播业务流量路径见图15带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
故障场景2--节点故障：
当C节点故障，转发流程如下：
(1)节点A和节点B上的转发过程同A-->C链路故障；
(2)节点D收到两份BIER报文，一份报文中P字段不置位，走原有转发流程， 剥BIER报文头；另一份报文中P字段置位(报文走保护环路径)，同A节点，查BRFT表项，BP7对应的表项匹配，因节点C故障，其状态为DOWN，满足条件C2；
(3)复制报文，清除P字段置位(BitString＝01110100)，转到BIFT转发流程，BIFT表项中BP5对应表项匹配，因是local-decap类型，报文在D节点需要剥离BIER报文头，BIER转发流程结束。BitString中其他置位的bit位在BIFT中无匹配表项。
上述故障时，组播业务流量路径，见图16带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
实施例九
本实施例结合实际情况进一步说明双环拓扑场景1下的故障保护过程，如图17所示的双环拓扑，在该双环拓扑场景下，链路B-->E上BP2(special-interconnected-link)配置TE-FRR保护，根据本公开方案，为其分配保护环BP8和9(图17中BP8为左边闭合环，逆时针方向，BP9为右边非闭合环，顺时针方向)
现在有一条组播业务，BFIR为B节点，BFER为A、D、F节点；在网络正常情况下，业务流量路径为B-->A，B-->E-->D，B-->E-->F，见图17带箭头直线条标记。
故障场景1--链路故障：
当B-->E链路发生故障，报文转发流程如下：
(1)B节点收到BIER报文，根据报文BitString(01111111)查找BIFT，匹配的BP为1和2；
(2)因BP1表项正常，则根据表项邻接信息将复制报文转发到下游节点A(后续该报文都是按照原有的转发流程进行，不是本公开内容，不做过多描述)；而链路B-->E故障，其关联的BP2状态为Down，查BTAFT表并更新报文BitString(AddBitMask＝110000000，ResetBitMask＝00001010)，更新后的BitString＝111110100，并且报文头中P字段置位；
(3)因P字段被置位，则需要查找对应BRFT表项，B节点BRFT表中BP8、BP9对应表项匹配，均不满足条件C2(即，需要继续沿保护环转发)
(4)复制一份报文，BitString不做修改，依然为111110100，分别通过不同邻接端口转发至下游节点A和节点C；
(5)节点A(节点D同节点A)收到P字段置位的BIER报文(报文走保护环路径)，查BRFT表项，BP8对应的表项匹配，不满足条件C2，复制报文(BitString＝111110100)转发至下游节点E；
(6)E节点收到BIER报文，P字段置位，查BRFT表项，BP8对应的表项匹配，因B-->E链路故障，其关联的BP8状态为DOWN，满足条件C2
(7)复制报文，清除P字段置位(BitString＝111110100)，转到BIFT转发流程，BIFT表项中BP3对应表项匹配，则从其对应邻接端口将报文转发至节点D (BitString＝111110000，后续流程是原有BIFT转发流程，不是本公开内容，不做描述)。
(8)接步骤(4)，节点C收到P字段置位的BIER报文(报文走保护环路径)，查BRFT表项，BP9对应的表项匹配，不满足条件C2，复制报文(BitString＝111110100)转发至下游节点F；
(9)F节点收到BIER报文，P字段置位，查BRFT表项，BP9对应的表项匹配，因其表项中DNR置为F，满足条件C2
(10)复制报文，清除P字段置位(BitString＝111110100)，转到BIFT转发流程，BIFT表项中BP7对应表项匹配，因是local-decap类型，报文在F节点需要剥离BIER报文头，BIER转发流程结束。BitString中其他置位的bit位在BIFT中无匹配表项
上述故障时，组播业务流量路径见图18所示带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
故障场景2--节点故障：
当E节点故障，转发流程如下：
(1)节点A、B、C、F上的转发过程同B-->E链路故障；
(2)节点D收到BIER报文，P字段置位(报文走保护环路径)，查BRFT表项，BP8对应的表项匹配，因节点E故障，其状态为DOWN，满足条件C2；
(3)复制报文，清除P字段置位(BitString＝111110100)，转到BIFT转发流程，BIFT表项中BP6对应表项匹配，因是local-decap类型，则报文在D节点需要剥离BIER报文头，BIER转发流程结束。BitString中其他置位的bit位在BIFT中无匹配表项。
上述故障时，组播业务流量路径，见图19所示带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
实施例十
本实施例结合实际情况进一步说明双环拓扑场景2下的故障保护过程，如图20所示的双环拓扑，在该双环拓扑场景下，链路A-->B上的BP1配置TE-FRR保护，根据本公开方案，为其分配保护环BP7和8(图20中BP8为小圆环线条，逆时针方向，BP9为大椭圆环线条，逆时针方向)
现在有一条组播业务，BFIR为A节点，BFER为C、F节点；在网络正常情况下，业务流量路径为A-->B-->C，A-->B-->E-->F，见图20带箭头直线条标记。
故障场景1--链路故障：
当A-->B链路发生故障，报文转发流程如下：
(1)A节点收到BIER报文，根据报文BitString(00111111)查找BIFT，匹配的BP为1；
(2)因链路A-->B故障，其关联的BP1状态为Down，查BTAFT表并更新报文BitString(Add BitMask＝11000000，Reset BitMask＝00000001)，更新后的BitString＝11111110，并且报文头中P字段置位；
(3)因P字段被置位，则需要查找对应BRFT表项，B节点BRFT表中BP7对应表项匹配(事实上BP7和BP8均匹配，参考实施例五的BRFT整合流程，BP7和BP8因为C-BM的原因，只能选择其中一条表项，本例中选择了BP7；在类似场景下，如何选择合适的BP的策略不是本公开关注重点)，不满足条件C2(即需要继续沿保护环转发)；
(4)复制一份报文，BitString不做修改，依然为11111110，通过邻接端口转发至下游节点D；
(5)节点D(节点E同节点D)收到P字段置位的BIER报文(报文走保护环路径)，查BRFT表项，同节点A，在BP7和BP8中选择BP7对应的表项，不满足条件C2，复制报文(BitString＝11111110)转发至下游节点E(节点B)；
(6)B节点收到BIER报文，P字段置位，查BRFT表项，BP7和BP8对应的表项匹配，因A-->B链路故障，其关联状态为DOWN，满足条件C2；
(7)复制报文，清除P字段置位(BitString＝11111110)，转到BIFT转发流程，BIFT表项中BP2和BP3对应表项匹配，则分别从对应邻接端口将报文转发至节点C和节点E(BitString＝11111000)；
(8)到节点C和节点E的报文(BitString＝11111000)，不带P置位，后续流程是原有BIFT转发流程，不是本公开内容，不做描述。
上述故障时，组播业务流量路径见图21带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
故障场景2--节点故障：
当B节点故障，转发流程如下：
(1)节点A、D上的转发过程同A-->B链路故障；
(2)节点E收到BIER报文，P字段置位(报文走保护环路径)，查BRFT表项，BP7对应的表项匹配，因节点B故障，其状态为DOWN，满足条件C2；
(3)复制报文，清除P字段置位(BitString＝11111110)，转到BIFT转发流程，BRFT表项中BP4对应表项匹配，则从其对应邻接端口将报文转发至下游节点F；同时更新原始报文(P标记置位)，将BitString中BP7对应位清除(BitString＝10111110)，再查BRFT表项，BP8对应表项匹配，不满足条件C2，则复制一份报文，BitString不做修改(BitString＝10111110)，通过邻接端口转发至下游节点F；
(4)节点F收到两份BIER报文，一份P标记不置位(BitString＝11111110)，按照原有BIFT转发流程，不做过多介绍；另一份P标记置位(BitString＝10111110)，查找BRFT，BP8对应表项匹配，不满足条件C2，则复制一份报文，BitString不做修 改(BitString＝10111110)，通过邻接端口转发至下游节点C；
(5)节点C收到BIER报文，P字段置位(报文走保护环路径)，查BRFT表项，BP8对应的表项匹配，因节点B故障，其状态为DOWN，满足条件C2；
(6)复制报文，清除P字段置位(BitString＝10111110)，转到BIFT转发流程，BIFT表项中BP5对应表项匹配，因是local-decap类型，则报文在C节点需要剥离BIER报文头，BIER转发流程结束。BitString中其他置位的bit位在BIFT中无匹配表项。
上述故障时，组播业务流量路径，见图22带箭头直线条标记，实线表示不受故障影响，虚线表示走保护环。
本公开实施例提出的BIER-TE网络故障保护方案是基于网络拓扑的，不关心具体组播业务，因此，在某些场景下，可能出现个别节点会收到双份流量的问题，文稿Draft-Eckert-Bier-Te-Frr提出的几种方案也同样存在此类问题，如何解决此问题，不在本公开范围内。
本公开实施例提出的BIER-TE中网络故障保护的方法、系统和存储介质，其为环形拓扑的每一转发链路分配保护环比特位置，其中，保护环比特位置的方向与相应的转发链路的工作路径相反设置。同时，新增一个BIER环转发表BRFT，以用于存放沿保护环比特位置的方向进行转发相关的邻接转发表项。这样一来，当BIER报文沿着该工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合该BRFT的表项内容将该BIER报文沿着该保护环比特位置的方向转发至对端故障点。如此一来，便可在BIER报文转发时，绕过故障转发链路，确保BIER报文成功转发至环形拓扑的每一正常节点。
上述本公开实施例序号仅仅为了描述，不代表实施例的优劣。
上面结合附图对本公开的实施例进行了描述，但是本公开并不局限于上述的具体实施方式，上述的具体实施方式仅仅是示意性的，而不是限制性的，本领域的普通技术人员在本公开的启示下，在不脱离本公开宗旨和权利要求所保护的范围情况下，还可做出很多形式，这些均属于本公开的保护之内。
工业实用性
本公开涉及网络技术领域。本公开提供的实施例通过保护环比特位置及新增BRFT，可在BIER报文转发时，绕过故障转发链路，确保BIER报文成功转发至环形拓扑的每一正常节点。

Claims (12)

  1. 一种网络故障保护的方法，包括以下步骤：
    为环形拓扑的每一转发链路分配保护环比特位置，所述保护环比特位置的方向与相应的所述转发链路的工作路径相反设置；
    新增一个BIER环转发表BRFT，所述BRFT用于存放沿所述保护环比特位置的方向进行转发相关的邻接转发表项；
    当BIER报文沿着所述工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点。
  2. 根据权利要求1所述的网络故障保护的方法，其中，所述BRFT包括位索引Index信息、邻接Adjacencies信息、标记DNR信息、转发时报文需要清除的位掩码C-BM信息以及表项状态Status信息。
  3. 根据权利要求1所述的网络故障保护的方法，其中，所述当BIER报文沿着所述工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点的步骤之前，还包括以下步骤：
    扩展所述BIER报文头部，通过新增字段来区分所述BIER报文是沿着所述工作路径还是沿着所述保护环比特位置的方向进行转发。
  4. 根据权利要求1所述的网络故障保护的方法，其中，所述BRFT的表项内容通过以下步骤形成：根据所述保护环比特位置的分配过程，对所述保护环比特位置所经过的每一节点进行BRFT表配置。
  5. 根据权利要求4所述的网络故障保护的方法，其中，所述当BIER报文沿着所述工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点的步骤之前，还包括以下步骤：
    通过南向接口将所述BIER报文转发相关的表项下发至所述BFR。
  6. 根据权利要求3所述的方法，其中，所述当BIER报文沿着所述环形拓扑进行转发时，若BIER转发路由器BFR检测到所述环形拓扑的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比 特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点的步骤具体包括：
    当所述BIER报文需要转发的下游邻接发生故障时，需要修改所述BIER报文的位字串内容，用故障转发链路的保护环比特位置替换故障转发链路的链路比特位置，同时将所述BIER报文头部的新增字段进行置位操作。
  7. 根据权利要求6所述的方法，其中，所述BIER报文转发时，根据所述BIER报文头部的新增字段是否置位，来决定是查找原来的位索引转发表BIFT还是查找新增的所述BRFT进行转发。
  8. 根据权利要求7所述的方法，其中，查找所述BRFT进行转发，通过以下步骤来完成：
    根据所述BIER报文头部的位字串进行按位复制转发，逐条查看所述BRFT的表项内容，以检测所述BRFT的当前表项是否满足下保护环的条件；
    若满足下保护环的条件，则将所述BIER报文头部的新增字段置位清除，复制所述BIER报文，并查找所述BIFT进行转发；
    若不满足下保护环的条件，则直接复制所述BIER报文，并从所述BRFT的当前表项对应的邻接端口转发出去。
  9. 一种网络故障保护的系统，包括：
    BIER-TE控制器，设置为为环形拓扑的每一转发链路分配保护环比特位置，所述保护环比特位置的方向与相应的所述转发链路的工作路径相反设置，新增一个BIER环转发表BRFT，所述BRFT用于存放沿所述保护环比特位置的方向进行转发相关的邻接转发表项，并通过南向接口将所述BIER报文转发相关的表项下发至BIER转发路由器；
    BIER转发路由器，设置为通过南向接口接收所述BIER-TE控制器发送过来的BIER报文转发相关的表项，并在BIER报文沿着所述工作路径进行转发时，若BIER转发路由器BFR检测到某一转发链路的下游邻接发生故障，则查找BIER-TE邻接快速重路由表BTAFT的表项内容，找出故障转发链路的链路比特位置与保护环比特位置之间的对应关系，并结合所述BRFT的表项内容将所述BIER报文沿着所述保护环比特位置的方向转发至对端故障点。
  10. 根据权利要求9所述网络故障保护的系统，其中，所述BIER-TE控制器包括以下模块：
    PCE模块，设置为计算每一所述转发链路的保护环路径，以及确定所述保护环路径所对应的保护环比特位置；
    环BP资源分配模块，设置为为每一所述转发链路分配保护环比特位置，以及确认所述保护环比特位置是否可以被共享；
    BRFT表项生成/整合模块，设置为根据所述保护环比特位置的分配情况生成初 始BRFT表，并按照BRFT整合方法对所述BRFT表的C-BM信息进行整合；
    保护关系管理模块，设置为管理每一所述转发链路的链路比特位置与保护环比特位置的对应关系；
    表项下发模块，设置为通过南向接口将所述BIER报文转发相关的表项下发至BIER转发路由器。
  11. 根据权利要求9所述网络故障保护的系统，其中，所述BIER转发路由器包括以下几个模块：
    表项配置模块，设置为通过南向接口接收所述BIER-TE控制器发送过来的BIER报文转发相关的表项；
    报文封装模块，设置为所述BIER报文的封装，包括修改所述BIER报文的位字串内容以及对所述BIER报文头部的新增字段进行置位操作；
    报文解析模块，设置为额外解析所述BIER报文头部的新增字段是否置位；
    报文发送/接收模块，设置为所述BIER报文的发送与接收操作；
    BIER-TE保护转发模块，设置为根据所述BIER报文头部的新增字段的置位情况，确定所述BIER报文是沿着所述工作路径还是沿着所述保护环比特位置的方向进行转发；
    BRFT转发模块，设置为根据所述BIER报文头部的新增字段并结合所述BRFT的表项内容来进行按位复制转发；
    快速检测模块，设置为通过快速检测技术手段，对所述环形拓扑中的每一转发链路进行连通性检测。
  12. 一种存储介质，所述存储介质存储有一个或者多个程序，所述一个或者多个程序可被一个或者多个处理器执行，以实现权利要求1至8中任一项所述的所述网络故障保护的方法的步骤。
PCT/CN2019/075689 2018-04-18 2019-02-21 一种网络故障保护的方法、系统和存储介质 WO2019201013A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US17/044,452 US11502896B2 (en) 2018-04-18 2019-02-21 Network failure protection method, system, and storage medium

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201810349035.4 2018-04-18
CN201810349035.4A CN110391977B (zh) 2018-04-18 2018-04-18 一种网络故障保护的方法、系统和存储介质

Publications (1)

Publication Number Publication Date
WO2019201013A1 true WO2019201013A1 (zh) 2019-10-24

Family

ID=68240450

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/075689 WO2019201013A1 (zh) 2018-04-18 2019-02-21 一种网络故障保护的方法、系统和存储介质

Country Status (3)

Country Link
US (1) US11502896B2 (zh)
CN (1) CN110391977B (zh)
WO (1) WO2019201013A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114520762A (zh) * 2020-10-30 2022-05-20 华为技术有限公司 BIERv6报文的发送方法以及第一网络设备

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110912816B (zh) * 2019-12-02 2021-07-20 北京邮电大学 链路重路由方法、装置和存储介质
CN113542188B (zh) * 2020-04-13 2023-04-18 华为技术有限公司 报文检测的方法以及第一网络设备
CN114531392A (zh) * 2020-11-03 2022-05-24 南京中兴软件有限责任公司 组播业务设计方法、服务器及存储介质
WO2022147162A1 (en) * 2020-12-30 2022-07-07 Futurewei Technologies, Inc. Bit index explicit replication traffic engineering for broadcast link
CN112887135B (zh) * 2021-01-22 2022-11-08 烽火通信科技股份有限公司 一种基于状态pce进行多点故障恢复的方法与装置
CN115242612B (zh) * 2022-07-22 2024-04-26 烽火通信科技股份有限公司 一种故障诊断方法和装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106341327A (zh) * 2015-07-08 2017-01-18 中兴通讯股份有限公司 一种bier报文的传输方法及系统
CN107135151A (zh) * 2016-02-26 2017-09-05 中兴通讯股份有限公司 报文发送方法及装置
CN107147508A (zh) * 2016-03-01 2017-09-08 中兴通讯股份有限公司 故障检测方法及装置
CN107204920A (zh) * 2016-03-18 2017-09-26 中兴通讯股份有限公司 一种快速重路由处理方法、装置和系统

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006030435A2 (en) * 2004-09-16 2006-03-23 Alcatel Optical Networks Israel Ltd. Efficient protection mechanisms for protecting multicast traffic in a ring topology network utilizing label switching protocols
US10003494B2 (en) * 2013-09-17 2018-06-19 Cisco Technology, Inc. Per-prefix LFA FRR with bit indexed explicit replication
US10341221B2 (en) * 2015-02-26 2019-07-02 Cisco Technology, Inc. Traffic engineering for bit indexed explicit replication
CN106572016B (zh) * 2015-10-09 2021-01-26 中兴通讯股份有限公司 路径计算方法及装置
CN107171977B (zh) * 2016-03-08 2021-08-17 中兴通讯股份有限公司 报文转发方法及装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106341327A (zh) * 2015-07-08 2017-01-18 中兴通讯股份有限公司 一种bier报文的传输方法及系统
CN107135151A (zh) * 2016-02-26 2017-09-05 中兴通讯股份有限公司 报文发送方法及装置
CN107147508A (zh) * 2016-03-01 2017-09-08 中兴通讯股份有限公司 故障检测方法及装置
CN107204920A (zh) * 2016-03-18 2017-09-26 中兴通讯股份有限公司 一种快速重路由处理方法、装置和系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
ECKERT, T. ET AL.: "Protection Methods for BIER-TE, draft-eckert-bier-te-frr-03", NETWORK WORKING GROUP INTERNET -DRAF T, 5 March 2018 (2018-03-05) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114520762A (zh) * 2020-10-30 2022-05-20 华为技术有限公司 BIERv6报文的发送方法以及第一网络设备
CN114520762B (zh) * 2020-10-30 2023-09-12 华为技术有限公司 BIERv6报文的发送方法以及第一网络设备
US11784919B2 (en) 2020-10-30 2023-10-10 Huawei Technologies Co., Ltd. Method for sending BIERv6 packet and first network device

Also Published As

Publication number Publication date
US11502896B2 (en) 2022-11-15
CN110391977A (zh) 2019-10-29
US20210105175A1 (en) 2021-04-08
CN110391977B (zh) 2021-11-09

Similar Documents

Publication Publication Date Title
WO2019201013A1 (zh) 一种网络故障保护的方法、系统和存储介质
CN112995029B (zh) 一种传输路径故障的处理方法、装置及系统
US9929938B2 (en) Hierarchal label distribution and route installation in a loop-free routing topology using routing arcs at multiple hierarchal levels for ring topologies
CN101155124B (zh) 一种实现组播快速重路由的方法
US7656792B2 (en) Method and apparatus for computing alternate multicast/broadcast paths in a routed network
US8711863B2 (en) Virtual links in a routed ethernet mesh network
US9264243B2 (en) Flooding and multicasting in a loop-free routing topology using routing arcs
CN105453491B (zh) 扩展远程lfa快速重新路由
CN108337157A (zh) 一种网络中传输报文的方法和节点
EP2880826B1 (en) Label distribution and route installation in a loop-free routing topology using routing arcs
US20090010272A1 (en) Root node shutdown messaging for multipoint-to-multipoint transport tree
US20100189113A1 (en) Link failure recovery method and apparatus
KR20130060170A (ko) 라우팅형 이더넷 네트워크에서의 분산형 장애 복구
CN103765808A (zh) 公用事业通信方法和系统
CN101436976A (zh) 一种转发数据帧的方法、系统和设备
US8934335B2 (en) System and method for enhancing loop free alternative coverage
US11627066B2 (en) IGP topology information and use for BIER-TE
CN102315967A (zh) 一种组播标签交换路径的中间节点保护方法及装置
CN102316014A (zh) 分层虚拟专用局域网服务环境下的负载分担方法及路由器
CN105704021A (zh) 一种基于弹性标签的重路由方法
CN106572012A (zh) 一种vpn frr的实现方法和pe设备
CN105591806B (zh) 一种链路切换方法及装置
JP2019510422A (ja) Ｓｄｎネットワークにおける迅速かつトポロジーに依存しない経路保護
CN111277495B (zh) 一种位索引显示复制组播的故障保护路径的预置方法
CN101529829A (zh) 链路状态协议控制以太网网络中的业务工程路径

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19787683

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 12/02/2021)

122 Ep: pct application non-entry in european phase

Ref document number: 19787683

Country of ref document: EP

Kind code of ref document: A1