CN101051854B - A heterogeneous media protection method for passive optical network - Google Patents

Abstract

The invention discloses a heterogeneous media protection method for a passive optical network, which is invented to solve the problems in the prior art that are complicated and need to define additional standard protocols. The line is divided into a VLAN; 2. Divide each protected port of the central office device into the VLAN where the port of the client device connected to the port is located; 3. Enable the MSTP protocol on the central office device and the client device, And set the port number of the main line to be less than the port number of the backup line; 4. When the main line fails, the MSTP will unshield the VLAN corresponding to the port of the backup line, and switch the service from the main line to the backup line , and shield the VLAN corresponding to the active line port. The invention is mainly applied to the heterogeneous media protection of the passive optical network. The invention does not need to define additional protocols, and the realization method is simple.

Description

A heterogeneous media protection method for passive optical network

technical field

The present invention relates to a protection method for a passive optical network (PON for short), in particular to a protection method for heterogeneous media of a passive optical network.

Background technique

PON is a single-fiber bidirectional optical access network that adopts Point To Multi Point (P2MP) structure. It consists of an optical line terminal (Optical Line Terminal, hereinafter referred to as OLT) (Optical Network Unit, hereinafter referred to as ONU) or optical network terminal (Optical Network Terminal, hereinafter referred to as ONT) and optical distribution network (Optical Distribution Network, hereinafter referred to as ODN). The typical topology of PON is a tree type, and ODN provides an optical transmission channel between the OLT at the central office and the ONU at the user side. ONU and ONT are collectively referred to as ONU in this document.

The protection reversal of PON means that in order to improve the security of the network, usually one or several backup lines will be set up in the PON network. Hereinafter referred to as wireless), when the main line fails, use the backup line to communicate to maintain the security of the network. When the system is working normally, the protection switching control module monitors the working status of the OLT PON module and related alarm information online. When the protection switching control module receives alarm information such as line failure and signal degradation from the OLT, it judges whether to Switching is performed, and the optical switch is triggered to realize switching, thereby realizing the active/standby switching of the backbone optical fiber of the PON system.

The point-to-multipoint shared medium characteristics of PON and the diversity of access network technologies complicate the protection of PON. At present, there are many schemes for PON protection in the industry, which are divided into two categories: same-media protection and different-media protection. Same-media protection means that both the main and backup lines use the PON network. Different-media protection means that the main line uses the PON network and the backup line uses the PON network. DSL or wireless. Each has advantages and disadvantages:

(1) Same medium protection: the A, B, and C types stipulated in the G.984.x series, among which B and C are more practical types, and most products implement these two types, specifically:

Type A: Type A protection, as shown in Figure 1a, only protects the backbone optical fiber without agreement, but the protection is slow and cannot be performed automatically.

Type B: As shown in Figure 1b, Type B protection also does not require a protocol, but the backup channel is in cold backup, so the protection is relatively slow.

Type C: Type C protection is shown in Figure 1c. Its protection protocol is specified in G.983.5. The protection is relatively fast and can support various protection working modes, such as 1+1/1:1 and load sharing. The disadvantage is that the entire ODN network is duplicated, which is relatively difficult and costly in actual construction and network planning.

(2) Heterogeneous media protection: There are many access technologies at the access level, such as PON, DSL and wireless. Heterogeneous media protection refers to the protection that introduces different media or different technologies as backup lines. Figures 2 to 5 are four typical network configuration modes of heterogeneous media protection modes.

Type a: As shown in Figure 2a, the OLT integrates PON and DSL, and performs service protection between PON and copper DSL. DSL provides protection channels for PON, and protection switching is realized between ONU and OLT;

Type b: As shown in Figure 2b, the OLT integrates the PON and BS, and protection is performed between the PON and the wireless. The wireless channel provides a protection channel for the PON, and the protection is performed between the ONU and the OLT;

Type c: As shown in Figure 2c, the OLT and BS are separated protection configurations. The OLT and BS are independent systems. The physical locations of these two systems can be arbitrary, and their Service Node Interfaces (ServicesNode Interface, hereinafter referred to as SNI) are connected at the same time To the upper Layer 3 switch, the protection is performed on the ONU and the Layer 3 switch;

Type d: As shown in Figure 2d, it is a separate protection configuration for OLT and Digital Subscriber Line Modem (hereinafter referred to as DSLM). OLT and DSLM are independent systems. The physical locations of these two systems can be arbitrary. The SNI interface is connected to the upper Layer 3 switch at the same time, and the protection is carried out on the ONU and the Layer 3 switch.

In several existing heterogeneous media protections, for protection types a and b, the PON interface already has a dedicated private secure tunnel (Private Secure Tunnel, hereinafter referred to as PST) to transmit protection switching control messages. If the PST message is to be used in For PON, it is necessary to develop similar protection switching control messages in DSL and wireless channels, which involves changes to existing DSL and wireless standards. For protection types c and d, since the main line PON and the backup line DSL or wireless equipment are independent of each other, and both are connected to the upper network through the SNI interface, it is necessary to connect the upper network equipment (three-layer switch in the figure) and ONU A channel for transmitting protection switching control messages is established between them. Since the uplink interfaces of OLT and DSL or wireless devices are usually Ethernet, it involves adding a protection switching control message channel on both the wireless network and the Ethernet network, and how to convert the PST message of the PON into an Ethernet communication channel. Protection switching messages in the channel. Therefore, it is very complicated to use in-band protection switching control messages to implement heterogeneous medium protection in the prior art, and the existing standards need to be extended and modified.

Contents of the invention

Aiming at the defects and deficiencies existing in the prior art, the purpose of the present invention is to propose a heterogeneous media protection method for passive optical networks, to overcome the complex implementation and the need to define additional standard protocols in the existing heterogeneous media protection methods. Problems and defects, providing a simple and efficient method for realizing PON network service protection.

In order to achieve the above object, the present invention proposes a heterogeneous media protection method for a passive optical network, including:

Step 1, dividing the port of each client device into at least one VLAN, which includes at least the protected main line port and backup line port of the client device in the VLAN;

Step 2, divide each protected port of the central office device into the VLAN where the client device port connected to the port is located;

Step 3, enabling Multiple Spanning Tree Protocol (Multiple Spanning Tree Protocol, hereinafter referred to as MSTP) at the Ethernet core of the central office equipment and the client equipment, and setting the port number of the main line to be less than the port number of the standby line;

Step 4. When the main line fails, MSTP unshields the VLAN corresponding to the standby line port, switches the service from the main line to the standby line, and shields the VLAN corresponding to the main line port.

Wherein, the step 3 is specifically:

Step 31, enabling MSTP on the Ethernet core of the central office equipment, and enabling MSTP on the Ethernet core of the user end equipment;

Step 32, setting the port number of the active line to be less than the port number of the standby line;

Step 33, MSTP shields the standby line port.

Among them, step 1 is specifically:

Step 11, dividing the ports of each client device into protected ports and unprotected ports;

Step 12, setting each client device, dividing a protected port of a client device into a VLAN;

Step 13, dividing the unprotected port of a client device into another VLAN;

Among them, the protected service can occupy equal bandwidth on the main line and the backup line.

Wherein, the method also includes:

Step 5. After receiving the service data, the client device judges whether the service data is protected data, and if so, sends the service data to the VLAN where the protected port is located, or sends the service data to the VLAN where the unprotected port is located.

The invention proposes a method for protecting heterogeneous media of a passive optical network. In the prior art, the Ethernet protocol must be redefined to be realized. The invention simplifies the process and improves the efficiency of PON protection by using MSTP. Specifically:

(1) The MSTP protocol is applied on the link layer and has nothing to do with specific technologies. It can work in DSL, PON, wireless and other technologies, and can be used for protection between the same technology and support protection between different technologies;

(2) ONU is the protection object: VLAN is divided by ONU, and the protection object is clear;

(3) Simple technical implementation: MSTP is a commonly used and mature technology in Ethernet. General Ethernet switches support this protocol. Supporting this protocol will not introduce additional costs, and the technology is very mature;

(4) It has nothing to do with the topology structure; enabling MSTP has nothing to do with the specific physical topology structure. It is suitable for GPON OLT and DSLAM or BS integrated topology and also suitable for GPON OLT and DSLAM or BS separation structure, and GPON OLT and DSLAM or BS can be placed in different physical location.

Description of drawings

Figure 1a is a schematic diagram of the structure of type a of existing same-media protection;

Figure 1b is a schematic diagram of the structure of type b of existing same-media protection;

Fig. 1c is a schematic structural diagram of type c of existing same-media protection;

Fig. 2a is a schematic structural diagram of type a of existing heterogeneous media protection;

Fig. 2b is a schematic structural diagram of type b of existing heterogeneous media protection;

Fig. 2c is a schematic structural diagram of type c of existing heterogeneous media protection;

Figure 2d is a schematic diagram of the type d structure of existing heterogeneous media protection;

Fig. 3 is the structural representation after adopting the method that the present invention proposes to divide VLAN;

Fig. 4 is a structural representation when the main line is disconnected after adopting the method proposed by the present invention;

Fig. 5 is the structural representation of central office equipment in the method that adopts the present invention;

Fig. 6 is a flowchart of a preferred embodiment of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

In the preferred embodiment of the present invention, a DSL line is used as a backup line, and the specific steps are as shown in Figure 6, including:

(1) Service configuration of OLT and ONU: first configure PON link and DSL link respectively, PON link is the main line, and DSL link is the backup line.

(2) divide the protected port of each ONU into a VLAN, promptly VLAN-ONU1 to VLAN-ONUnn as shown in Figure 3; Simultaneously divide the unprotected port of each ONU into another VLAN, promptly as Figure 3 shows VLAN1 to VLANn. In order to ensure the SLA (service-level agreement, quality of service agreement) of switching from the active service channel to the standby service channel, the services that need to be protected here can occupy equal bandwidth on the PON and DSL links.

(3) Divide each port of the OLT and the port connected to the ONU side device into the same VLAN.

(4) The device on the ONU side can judge whether the service is a protected service according to the key field, and forward the service that needs to be protected to the protection VLAN (that is, VLAN-ONU1 to VLAN-ONUn). Forward to other VLANs (VLAN1 to VLANn). On the OLT side, in order to reduce the requirement for the number of VLANs on the upper layer network, the VLAN conversion function shown in Figure 5 should be supported, that is, multiple VLANs from different ports can be converted to the same SVLAN (stackable VLAN) on the same uplink, and Sent out from the SNI interface, the data packet with SVLAN coming down from the SNI can find the original upstream VLAN, replace the SVLAN with the VLAN corresponding to the downlink port, and send it out from the corresponding downlink port. The key fields mentioned above may be Type of Service/Class of Service (TOS/COS), DA-MAC, SA-MAC, SA-IP, and DA-IP fields.

(5) Load MSTP to prevent the business from forming an infinite loop: Since both OLT and ONU are based on Ethernet switching as the core, and MSTP is started on the ONU and OLT Ethernet switching core at the same time, the port number of the DSL port needs to be set to be higher than that of the PON port. The port number is large. In this way, according to the MSTP protocol, if a loop is to be formed, the port number will block the wide port with a larger port number in the loop, and the VLAN corresponding to the DSL port will be blocked (BLOCK), so as to ensure that the business is only transmitted on the PON link, and the No loop will be formed.

(6) When the main line fails: When the PON link between the PON ONU and the OLT fails, the multiple spanning tree will unshield the VLAN corresponding to the DSL port in the shielded ONU in step (5), and the PON port The corresponding VLAN is shielded, so that the service is switched from the PON port to the corresponding DSL interface.

As shown in Figure 4, assuming that the PON port of the first ONU fails, the VLAN-ONU1 corresponding to the PON port is shielded, and the service is switched to the CopperNetwork between the DSL LTs of ONU1 to continue normal operation.

Claims (2)

1. the irregular medium protecting method of an EPON comprises:

Step 1, the port of each ustomer premises access equipment is marked off at least one VLAN, comprise the shielded main of this ustomer premises access equipment among this VLAN at least with line port and extension wire port; Wherein, described main be the passive optical network line port with line port, described extension wire port is the line port with different mediums of described passive optical network line port or different technologies;

Step 2, with each shielded port of local side apparatus, be divided among the VLAN at the ustomer premises access equipment port place that links to each other with this port;

Described ustomer premises access equipment judges according to critical field whether business is shielded business, and the business that needs protection is forwarded to protection VLAN, then is forwarded in other VLAN for the business that does not need protection; Described local side apparatus will be transformed into the same VLAN of piling up of the same first line of a couplet from a plurality of VLAN of different port; Described protection VLAN is the VLAN at protected port place, and described other VLAN are the VLAN at protected port place not;

Step 3, enable Multiple Spanning Tree Protocol, and set the port numbers of main port numbers with circuit less than extension wire at local side apparatus and ustomer premises access equipment Ethernet core;

Step 4, when main when use line failure, Multiple Spanning Tree Protocol deshields the VLAN of extension wire port correspondence, and with business from main with line switching to extension wire, and the VLAN that will lead with the line port correspondence shields;

Described step 3 is specially:

Step 31, the Ethernet core of local side apparatus is enabled Multiple Spanning Tree Protocol, the Ethernet core of ustomer premises access equipment is enabled Multiple Spanning Tree Protocol;

Step 32, the main port numbers of using the port numbers of circuit less than extension wire of setting;

Step 33, Multiple Spanning Tree Protocol are with the extension wire portmask;

Described step 1 is specially:

Step 11, the port of each ustomer premises access equipment is divided into protected port and non-protected port;

Step 12, each ustomer premises access equipment is provided with, the protected port of a ustomer premises access equipment is divided into a VLAN;

Step 13, the not protected port of a ustomer premises access equipment is divided into another VLAN.

2. the irregular medium protecting method of a kind of EPON according to claim 1 is characterized in that, protected business can take equal bandwidth on leading with circuit and extension wire.

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