KR20050006442A - Apparatus and method for monitoring packet delay in multiprotocol label switching domain - Google Patents

Abstract

PURPOSE: An apparatus and a method for measuring a transmission delay in an MPLS(MultiProtocol Label Switching) domain are provided to measure a transmission delay time with respect to generated/deleted/changed LSP(Label Switched Path) and CR-LSP(Constraint Based-LSP) by using a probe packet. CONSTITUTION: An operator terminal(100) generates a transmission delay measurement request with respect to one specific path of different LSP paths set between two switch routers positioned at a boundary of an MPLS domain, and receives and displays a response to the request on a screen. An MAS(Maintenance and Administration System)(101) receives the transmission delay measurement request, generates a request data unit including information for discriminating the specific path and transmits it to a packet processor(103), and calculates the transmission delay time with respect to the specific path and transmits it to the operator terminal(100) when a response data unit with respect to the request data unit is received. The packet processor(103) converts the data unit received from the MAS(101) into an IP packet and transfers it to a forwarding engine(107-2), and converts an IP packet received from the forwarding engine(107-2) into a data unit of an application part and transfers it to the MAS(101). A label mapping table(108) stores MPLS label values with respect to LSP paths. The forwarding engine(107-2) reads an MPLS label value with respect to one specific path, MPLS-encapsulates the IP packet received from the packet processor(103), and transfers a probe packet to the other switch router. When the forwarding engine(107-2) receives a response packet with respect to the probe packet from the other switch router, it MPLS-decapsulates the response packet and transfers an IP packet to the packet processor(103).

Description

Apparatus and method for measuring transmission delay in a multiprotocol label switching domain {APPARATUS AND METHOD FOR MONITORING PACKET DELAY IN MULTIPROTOCOL LABEL SWITCHING DOMAIN}

The present invention relates to an apparatus and a method for measuring a transmission time using a probe packet, and more particularly, to a Label Switched Path (LSP) and a Constraint Based LSP (CR-LSP) that are generated, deleted, or changed in a MPLS domain An apparatus and method for measuring a transmission delay time using a probe packet.

In general, a method of measuring a transmission delay of a path using probe packets in an Internet Protocol (IP) network includes a program using an echo request / reply function of the Internet Control Message Protocol (ICMP) protocol. use.

When the LSP / CR-LSP transmission delay time measurement is performed by using the echo request / reply function of the ICMP protocol, since the route is determined using the routing table information, the route may have various routes to the destination. In case of CR-LSP, transmission delay time cannot be measured. In addition, since the QoS characteristics can be set differently between LSPs / CR-LSPs configured in the same physical path, for the ICMP protocol transmitted with the best-effort characteristic, different QoS can be obtained by using the echo request / replay function. The transmission delay time of the LSP / CR-LSP with characteristics cannot be measured.

For example, referring to FIG. 1, the path from the switch router Ra to Rb includes a first path (LSP) for a best-effort service, a second path for a VPN service (CR-LSP), and a VOIP. There is a third path (CR-LSP). Assuming that the shortest path from Ra to Rb is composed of {Ra, Ca, Cb, Rb} by a routing protocol, a packet for a second path for a VPN service using an echo request / response function of the ICMP protocol is assumed. Transmission delay time cannot be measured. In addition, although the same path is used, the first path (LSP) and the third path for VOIP (CR-LSP) have different IP QoS settings. The packet transmission delay time for the third path cannot be measured.

That is, because the ping function using the echo request / reply function of the existing ICMP protocol uses hop-by-hop packet transmission using a destination address, the LSP Alternatively, the transmission delay time for each CR-LSP cannot be measured. In addition, in case of an ATM-based MPLS system that sets up a data path LSP or CR-LSP and a control path separately, the transmission delay of the LSP or CR-LSP is performed using the echo request / reply function of the ICMP protocol. You can't measure time.

Accordingly, an object of the present invention is to provide an apparatus and method for measuring a transmission delay time for different paths set between two switch routers located at MPLS domain boundaries.

According to a first aspect of the present invention for achieving the above object, in a switch router device located at the boundary of the Multiprotocol Label Switching (MPLS) domain, a method for transmitting a transmission delay measurement request packet and receiving and processing a response packet, MPLS Storing MPLS label values for LSP (Label Switched Path) paths established through a signaling protocol in a label mapping table, and different LSPs configured between the switch router and another switch router located at the domain boundary Path) receiving a transmission delay measurement request for a particular one of the paths from the operator terminal, generating a request data unit including information for identifying the specific path when the request is received; The process of creating an IP packet with a request data unit and the label mapping table Accessing and reading an MPLS label value for the specific one path, MPLS encapsulating the IP packet with the MPLS label value, and transmitting a probe packet to the other switch router; Generating an IP packet by MPLS decapsulating the response packet when receiving a response packet for the probe packet from a router, extracting a response data unit for the request data unit from the IP packet; And calculating the transmission delay time for the specific path with the request data unit generation time and the response data unit reception time and transmitting the calculated delay time to the operator terminal.

According to a second aspect of the present invention, a method for receiving a transmission delay measurement request packet and transmitting a response packet in a switch router device located at a MultiProtocol Label Switching (MPLS) domain boundary includes LSP paths configured through an MPLS signaling protocol. Storing MPLS label values in a label mapping table, and transmitting delay for a specific one of different LSP (Label Switched Path) paths established between the switch router and another switch router located at the domain boundary. Upon receiving a probe packet requesting measurement, MPLS decapsulation of the probe packet to generate an IP packet, extracting application data from the IP packet, and interpreting the application data to obtain a response data unit. Creating an IP packet with the response data unit, Accessing the table mapping table to read the MPLS label value for the specific one path; and MPLS encapsulation of the IP packet with the read MPLS label value to convert the response packet to the probe packet into the other packet. Characterized in that the transmission to the switch router.

1 is a diagram illustrating various paths (LSP / CR-LSP) established between two switch routers located at an MPLS domain boundary.

2 is a diagram illustrating a system configuration according to an embodiment of the present invention.

3 is a diagram illustrating a procedure for transmitting a transmission delay measurement request packet and receiving and processing a response packet in a switch router located at an MPLS domain boundary according to an embodiment of the present invention.

4 is a diagram illustrating a procedure for receiving a transmission delay measurement request packet and transmitting a response packet at a switch router located at an MPLS domain boundary according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 shows a system configuration according to an embodiment of the present invention. In particular, FIG. 2 shows a configuration of a switch router located at a boundary of a multiprotocol label switching (MPLS) domain.

As shown, the switch router, the operator terminal 100, the management system (MAS: Maintenance & Administration System) (101), UDP (User Datagram Protocol) packet processing unit 102, IP (Internet Protocol) packet processing unit ( 103, Inter-Processor Communication (IPC) 104-1, 104-2, 104-3, Resource Manager (RM) 105, Switch 106, Forwarding Engine (FE) Forwarding engines 107-1 and 107-2, and a label mapping table (FTN: FEC-to-NHLFE Map) 108.

Referring to FIG. 2, first, an operator terminal 100 transmits a command input by an operator to the management system 101, and performs a human machine interface (HMI) function for receiving and displaying the command result. do.

The resource manager 103 manages system resources, for example, manages resources (channel information, source address, destination address, source layer 4 port, destination layer 4 port, protocol ID, etc.) for the set LSP paths. do. The management system 101 prepares a predetermined protocol data unit (PDU) and sends it to the UDP packet processor 102, and the UDP packet processor 102 interprets the received protocol data unit. The result is transmitted to the operator terminal 100.

The UDP packet processing unit 102 generates a UDP datagram (or UDP packet) with a protocol data unit (PDU) from the management system 101 and transmits the UDP datagram (or UDP packet) to the IP packet processing unit 103, and the IP packet processing unit ( Application unit data is extracted from the UDP datagram from 103 and transmitted to the management system 101. The IP packet processing unit 103 creates an IP datagram (or IP packet) with the UDP datagram from the UDP packet processing unit 102 and delivers the IP datagram (or IP packet) to the interprocessor communication unit 104-1 of the main processor. The UDP datagram is extracted from the TCP / IP packet from the intercommunication unit 104-1 and transferred to the UDP packet processing unit 102.

The interprocessor communication unit 104-1 of the main processor generates an IPC message including an IP datagram from the IP packet processing unit 103 and channel information of a specific LSP path, and generates an IPC message through an internal switch 106. The packet is delivered to the IPC 104-3, and the IP packet is extracted from the received IPC message and delivered to the IP packet processor 103. The IPC 104-3 extracts the TCP / IP packet and the channel information from the IPC message and forwards it to the forwarding engine 107-2. Here, the channel information is received from the resource manager 105.

The forwarding engine 107-2 accesses the label mapping table 108 with the received LSP channel information to obtain an MPLS label value, and prints an MPLS label in the TCP / IP packet received from the IPC 104-3. Encapsulation is performed to the MPLS network, MPLS decapsulates the packet received from the MPLS, and the TCP / IP packet is delivered to the IPC 104-3. Here, the label mapping table 108 manages the MPLS label value for the set LSP path (channel information). The label value is pre-assigned by the MPLS signaling protocol (LDP, CR-LDP, RSVP_TE).

The operation based on the configuration of FIG. 2 is as follows.

First, the operator enters the following command (operation command). The operation command includes various parameters for determining a transmission delay time measurement target LSP path (LSP or CR-LSP).

<Operation Instruction>

MPLS-PING:

DESTADDR [, CRLSPID] [, RDESTADDR] [, RSRCADDR] [, RPROTOID] [, RDESTPORT] [, RSRCPORT] [, DSIZE] [, COUNT];

DESTADDR: IP address of the MPLS boundary switch router on which the LSP or CR-LSP is terminated.

CRLSPID: ID set in CR-LSP when transmission delay measurement target is CR-LSP.

RDESTADDR: Destination address of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS perimeter switch router where the LSP / CR-LSP is terminated.

RSRCADDR: The source address of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch router where the LSP / CR-LSP is terminated.

RPROTOID: The protocol ID (ID) of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS perimeter switch router where the LSP / CR-LSP is terminated.

RDESTPORT: The destination port number of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch routers on which the LSP / CR-LSP is terminated.

RSRCPORT: The source port number of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch router where the LSP / CR-LSP is terminated.

DSIZE: Specifies the data size.

COUNT: Specify the number of times to measure the transmission delay time.

The operator terminal 100 receiving the command as described above transfers the command processing request to the management system 101. Then, the management system 101 requests the resource management unit 105 for output information of the measurement target path (LSP / CR-LSP). The output information is port information included in a PDU, and means TCP / UDP port information of layer4. The resource manager 105 retrieves the output information of the measurement target path and notifies the management system 101. The management system 101 receiving the output information of the path to be measured (LSP / CR-LSP) prepares a data format (PDU) for measuring a transmission delay time of the path (LSP / CR-LSP) to the UDP. Transfer to the packet processing unit 102. Here, look at the message format of the protocol data unit (PDU) generated by the management system 101 as shown in Table 1 below.

0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 Seq number Type Data length Protocol ID Estaddr Srcaddr Estport Srcport Data

Seq Number: Message serial number.

Type: The message type. (Request or reply)

Data Length: Length of the Data field without headers.

Protocol ID: The reverse path protocol ID for retrieving the reverse LSP / CR-LSP from the MPLS perimeter switch router where the LSP / CR-LSP is terminated.

DestAddr: The reverse path destination IP address for retrieving the reverse LSP / CR-LSP from the MPLS border switch router where the LSP / CR-LSP is terminated.

SrcAddr: The source address of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch router where the LSP / CR-LSP is terminated.

DestPort: The destination port number for the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch routers on which the LSP / CR-LSP is terminated.

SrcPort: The source port number of the reverse path for retrieving the reverse LSP / CR-LSP from the MPLS border switch router where the LSP / CR-LSP is terminated.

Data: Null Dat

The UDP packet processor 102 receiving the data unit as shown in Table 1 creates a UDP datagram as shown in Table 2 and transmits the UDP datagram to the IP packet processor 103.

0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 Seq number Type Data length Protocol ID Estaddr Srcaddr Estport Srcport Data UDP Header + UDP Payload

Receiving the UDP datagram as shown in Table 2, the IP packet processing unit 103 creates an IP datagram as shown in Table 3 and delivers it to the IPC 104-1 of the main processor.

0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 0 One 2 3 4 5 6 7 Seq number Type Data length Protocol ID Estaddr Srcaddr Estport Srcport Data UDP Header + UDP Payload IP Header + IP Payload

The interprocessor communication unit 104-1 receiving the IP datagram as shown in Table 3 creates a TCP / IP packet, and stores channel information of the TCP / IP packet and the path (LSP / CR-LSP). The IPC message including the generated message is transmitted to the forwarding engine 107-2. The IPC message is transmitted to the IPC 104-3 of the interface processor on which the forwarding engine 107-2 is mounted via the internal switch 106. The IPC 142-2 extracts the TCP / IP packet and channel information of the path from the IPC message, and forwards the forwarding engine 107-2. Then, the forwarding engine 107-2 accesses a label mapping table with the channel information to obtain an MPLS label value, and performs MPLS label encapsulation on the TCP / IP packet to generate a request packet (probe packet). Create and send to MPLS network.

Then, upon receiving a response packet for the request packet, the forwarding engine 107-2 performs MPLS decapsulation on the response packet to deliver a TCP / IP packet to the IPC 104-3, and the IPC 104-3 converts the TCP / IP packet into an IPC message and forwards it to the IPC 104-1 of the main processor. Then, the IPC 104-1 extracts the TCP / IP packet from the IPC message and transfers it to the IP packet processor 103. The IP packet processor 103 decapsulates the TCP / IP packet and delivers a UDP datagram to the UDP packet processor 102. The UDP packet processing unit 102 extracts the application unit data from the UDP datagram and delivers it to the management system 101. Then, the management system 101 interprets the application unit data, calculates a transmission delay time (RTT: Round Trip Time) for a predetermined path (LSP / CR-LSP), and transmits it to the operator terminal 100. . The management system 101 stores the time at which the data unit is delivered to the UDP packet processing unit 102 as a start time, and stores the time at the time of receiving the data unit from the UDP packet processing unit 102. A final time is defined, and a round trip time (RTT) is calculated based on the end time and the start time.

3 illustrates a procedure for transmitting a transmission delay measurement request packet and receiving and processing a response packet in a switch router located at an MPLS domain boundary according to an exemplary embodiment of the present invention.

Referring to FIG. 3, an operator terminal (or a human machine interface) first receives a command input by an operator in step 301, and transmits a message requesting processing of the command to a management system MAS in step 303. In step 305, the management system MAS obtains output information (port information) for the measurement target path LSP / CR-LSP. In operation 307, the management system MAS generates a data format (command processing data) for measuring transmission delay time of the measurement target path and transmits the data format (command processing data) to the UDP packet processor. At this time, the management system MAS stores the current time as a start time of packet transmission. In step 309, the UDP packet processing unit receiving the command processing data is encapsulated in the command processing data, and a UDP datagram is delivered to the IP packet processing unit, and the IP packet processing unit encapsulates the UDP datagram in step 311. IP datagrams are sent to the IPC of the main processor. Then, in step 313, the IPC of the main processor generates an IPC message including an IP packet and channel information (obtained from the resource manager) of the measurement target path, and delivers the IPC message to the IPC of the interface processor. Extract IP channel and channel information of measurement target path from IPC message and forward it to forwarding engine. In step 317, the forwarding engine accesses a label mapping table with the channel information to obtain an MPLS label value, and performs MPLS encapsulation on the IP packet to generate a transmission packet (or a probe packet). In step 319, the forwarding engine transmits the generated packet to a router located at the boundary of the MPLS domain.

In step 321, the forwarding engine receives a response packet for the transmission packet, and in step 323, MPLS decapsulates the received response packet and delivers a TCP / IP packet to the IPC of the interface processor. Then, the IPC converts the TCP / IP packet into an IPC message in step 325 and delivers it to the IPC of the main processor, and the IPC of the main processor converts the IPC message into a TCP / IP packet in step 327. Deliver to packet processing unit. The IP packet processor decapsulates the TCP / IP packet in step 329 to deliver a UDP packet to the UDP packet processor, and the UDP packet processor decapsulates the UDP packet in step 331 to store the application data. Transfer to management system (MAS). Then, the management system interprets the application unit data received in step 333, calculates the transmission delay time (RTT) and delivers it to the operator terminal. Here, the transmission delay time is calculated by subtracting the start time from the time (end time) of receiving the application data. The operator terminal receives the transmission delay time in step 335, and displays the transmission delay time on the screen in step 337.

4 illustrates a procedure for receiving a transmission delay measurement request packet and transmitting a response packet at a switch router located at an MPLS domain boundary according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the forwarding engine first receives a packet (probe packet) from the MPLS network in step 401, and MPLS decapsulates the received packet to the IPC of the interface processor in step 403. Then, the IPC converts the data unit from the forwarding engine to an IPC message in step 405 and delivers it to the IPC of the main processor, and the IPC of the main processor sends a protocol data unit (TCP / IP packet) in the IPC message received in step 407. ) And pass it to the IP packet processor. Then, the IP packet processing unit decapsulates the protocol data unit in step 409 to transfer the UDP packet to the UDP packet processing unit, and the UDP packet processing unit decapsulates the UDP packet received from the lower layer in step 411 to provide a protocol. Deliver the data unit (application data) to the management system (MAS). The management system then analyzes the protocol data unit passed in step 413. At this time, the management system confirms that the received packet is a probe packet for requesting transmission delay measurement. The management system confirming that the received packet is a probe packet, in step 415, obtains output information (port information) of the reverse path (LSP / CR-LSP) based on the information obtained from the protocol data unit.

In step 417, the management system generates a response data unit for the received packet, copies the sequence number of the received packet to the data unit, and transfers the received packet to the UDP packet processor. The UDP packet processor encapsulates the data unit received from the upper stage in step 419 and delivers the UDP packet to the IP packet processor, and the IP packet processor encapsulates the UDP packet received in step 421 to the IPC of the main processor. To pass. Then, the IPC of the main processor generates an IPC message including the protocol data unit received in step 423 and channel information of the reverse path (LSP / CR-LSP), and delivers the IPC message to the IPC of the interface processor. IPC extracts the TCP / IP packet and the channel information from the IPC message received in step 425 and delivers the information to the forwarding engine. Then, the forwarding engine accesses a label mapping table with the channel information in step 427 to obtain an MPLS label value, and generates a response packet by encapsulating the TCP / IP packet in MPLS label, in step 429. The response packet is sent to the switch router that sent the request packet through the MPLS network.

Referring again to FIG. 1, Ra, Rb, Rc, and Rd are routers or router switches supporting MPLS, located at the boundary of the MPLS domain, classifying packets received from the non-MPLS domain, and classifying the packets into LSP or CR-LSP. Send to the destination via the route.

In the drawing, an LSP path composed of {Ra, Ca, Cb, and Rb} is generated depending only on routing information. And CR-LSP composed of {Ra, Ca, Cb, Rb} provides a differentiated quality according to the routing information and the information set in the path applying the traffic control information and the routing information set by the operator's policy. And, CR-LSP composed of {Ra, Ca, Cd, Cb, Rb} provides a differentiated quality according to the routing information and the information set in the path applying the traffic control information and the routing information set by the operator's policy.

When measuring the transmission delay time between Ra and Rb using the echo request / reply function of the ICMP protocol, the packet is transmitted to the LSP composed of {Ra, Ca, Cb, and Rb}. However, the present invention exists between two nodes because the LSP or CR-LSP configured between Ra and Rb is transmitted to transmit a probe packet for transmission delay measurement and receive a response packet to measure the transmission delay time. Transmission delay time can be measured for different paths.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As described above, the present invention can measure the transmission delay time for the LSP set by referring to the route information determined by the routing protocol, the CR-LSP set by the operator or the network management system, the policy management system, etc. Let's do it. In addition, there is an advantage that the transmission delay time can be measured for LSP and CR-LSP having the same physical path but different QoS conditions.

Claims (5)

In the switch router device located at the Multiprotocol Label Switching (MPLS) domain boundary, A transmission delay measurement request is generated for a specific one of different LSP (Label Switched Path) paths established between the switch router and another switch router located at the domain boundary, and receives a response to the request. Operator terminal to display on, When the request is received, a request data unit including information for identifying the specific path is generated and transmitted to a packet processing unit, and when a response data unit for the request data unit is received from a lower layer, a transmission delay time for the specific path is received. And the management system for calculating the transmission to the operator terminal, A packet processing unit converting a data unit from the management system into an IP packet and transferring the data unit to a forwarding engine, converting the IP packet from the forwarding engine into a data unit of an application unit, and delivering the data unit to the management system; A label mapping table that stores MPLS label values for LSP paths established through the MPLS signaling protocol; Access the label mapping table to read the MPLS label value for the specific one path, and encapsulate the IP packet from the packet processor with the read label value to transmit the probe packet to the other switch router. And a forwarding engine that MPLS decapsulates the response packet and delivers the IP packet to the packet processing unit upon receiving the response packet for the probe packet from the other switch router. The method of claim 1, wherein the packet processing unit, A UDP packet processing unit which prepares a UDP packet with a request data unit from the management system and delivers the UDP packet to the IP packet processing unit, creates a UDP packet with the IP packet from the IP packet processing unit, and delivers the UDP packet to the management system; Including an IP packet from the UDP packet processing unit to create an IP packet and delivers it to the forwarding engine, and an IP packet processing unit for creating a UDP packet with the IP packet from the forwarding engine to deliver to the UDP packet processing unit. Characterized in that the device. The method of claim 1, The packet processing unit and the forwarding engine, characterized in that the communication via IPC (Inter Processor Communication). In the switch router device located at the Multiprotocol Label Switching (MPLS) domain boundary, a method for transmitting a transmission delay measurement request packet and receiving and processing a response packet, Storing MPLS label values for LSP (Label Switched Path) paths set through the MPLS signaling protocol in a label mapping table; Receiving, from an operator terminal, a transmission delay measurement request for a specific one of different LSP (Label Switched Path) paths established between the switch router and another switch router located at the domain boundary; Generating, upon receipt of the request, a request data unit comprising information for identifying the particular path; Creating an IP packet with the request data unit; Accessing the label mapping table to read an MPLS label value for the specific single path; Sending the probe packet to the other switch router by encapsulating the IP packet with the MPLS label value and performing MPLS encapsulation; Generating an IP packet by MPLS decapsulating the response packet when receiving a response packet to the probe packet from the other switch router; Extracting a response data unit for the request data unit from the IP packet; And calculating the transmission delay time for the specific path with the request data unit generation time and the response data unit reception time and transmitting the calculated delay time to the operator terminal. In the switch router device located at the Multiprotocol Label Switching (MPLS) domain boundary, a method for receiving a transmission delay measurement request packet and transmitting a response packet, Storing MPLS label values for LSP paths established through the MPLS signaling protocol in a label mapping table; When receiving a probe packet requesting transmission delay measurement for a specific one of different LSP (Label Switched Path) paths established between the switch router and another switch router located at the domain boundary, the probe packet is MPLS decoded. To encapsulate the IP packet, Extracting application part data from the IP packet; Interpreting the application unit data to create a response data unit; Creating an IP packet with the response data unit, Accessing the label mapping table to read an MPLS label value for the specific single path; And MPLS encapsulating the IP packet with the read MPLS label value and transmitting a response packet to the other switch router to the other switch router.