KR20010057772A - A apparatus for high speed ip header lookup control in mpls label edge router - Google Patents

Abstract

PURPOSE: An apparatus for controlling a lookup of a high-speed IP(Internet Protocol) header in an edge router of an MPLS(Multi-Protocol Label Switching) network, is provided to improve lookup process efficiency, by processing the lookup based on hardware in parallel using a control circuit, and expanding an IP lookup table without connection of each device in series. CONSTITUTION: An IP packet header receiver(301) receives IP packet information and IP header information. An IP packet header test part(302) recognizes a packet type of the packet information. An IP header label extraction part(303) recognizes an IP header area, and thereby extracts an IP header and an MPLS label. An IP packet header test part(304) performs a test function. A lookup data/control generation part(306) controls a control signal for performing the lookup, an IP target place address and an originating place address. A lookup device interface part(307) provides a function for interfacing with a lookup device. A label information interface part(308) fetches label information from a label information table, and then stores it in a storage part(309). A transmission header change sort part(310) extracts desired information, and sorts it.

Description

A look-up control device for a high-speed Internet protocol header in an edge router of a multiprotocol label switching network {A APPARATUS FOR HIGH SPEED IP HEADER LOOKUP CONTROL IN MPLS LABEL EDGE ROUTER}

The present invention can perform high-speed Internet Protocol (IP) lookup control in hardware for Internet Protocol (IP) packets having various packet types in an edge router of a Multi Protocol Label Switching (MPLS) network. A look-up control device.

Conventionally, a look-up control for an IP header is processed by a software method using a high performance CPU, and the look-up itself uses many algorithms for retrieving entries stored in memory.

This method of processing headers using a high performance CPU can improve the speed to some extent, but the time required to process the CPU's instructions is fundamentally higher than that of hardware. This takes a lot of time, and the CPU itself executes instructions sequentially in time.

Accordingly, an object of the present invention is to provide a control circuit for hardware-based lookup without using a CPU for IP packet extraction and IP packet header processing for various packet types, that is, PPP protocol, RFC1483 packet type, and MPLS-labeled IP packet. In order to provide a look-up control apparatus that performs parallel processing and improves look-up processing efficiency by processing each element in parallel without connecting in series for expansion connection of an IP lookup table.

1 is a block diagram of a look-up related function of the edge router to which the present invention is applied.

2 is a detailed structural diagram of a packet header for each packet type.

3 is a block diagram of an IP lookup control unit according to the present invention;

4 is a diagram showing a length offset value generation structure and an output value table.

5 is a flowchart for explaining the operation of the IP lookup control apparatus according to the present invention;

* Explanation of symbols for main parts of the drawings

301: IP packet header receiver 302, 304: IP packet header checker

303: IP header / label extraction unit 305: CPU matching and arbitration unit

306: lookup data / control signal generator 307: lookup device matching unit

308: label information (LIB) matching unit 309: label information (LIB) storage unit

310: transmission header change and alignment unit 311: IP packet header transmission unit

The present invention for achieving the above object, in the look-up control apparatus of the Internet Protocol (IP) packet in the edge router of the multi-protocol label switching (MPLS) network including a look-up apparatus and a label information table, the Internet protocol packet header Receiving and processing means for receiving a packet, checking a type and an error of a packet, and extracting a header and a label of a received packet according to the type of the analyzed packet; Lookup data / control signal generating means for receiving an IP header and an error presence signal from the receiving and processing means and providing a control signal and an IP address for performing a lookup to the lookup performing apparatus; Label information fetching means for receiving an index as a result of performing a lookup from the lookup performing apparatus, fetching and storing label information corresponding to the index from the label information table; And header alignment and transmission means for extracting various types of information from the label information stored by the label information fetching means, rearranging the information according to the header format of the transmission packet, and inserting and inserting checksum information and offset for the new header. Characterized in that.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a lookup-related functional block of an edge router to which the present invention is applied, which includes an IP lookup control apparatus 100, a lookup performing apparatus 110, and a label information table 120. The lookup performing apparatus 110 includes a layer-3 lookup unit 113, a layer4 lookup unit 112, and an MPLS label comparison unit 111. The layer 3 lookup unit 113 searches for an entry address with matched data by referring to a destination address in the IP header area, and the layer 4 lookup unit 112 performs a destination address, a source address, The destination address and source port address of the TCP header are used to retrieve the entry address with the matched data. The MPLS label comparison unit 111 searches for an entry address that matches the MPLS label when the header of the packet received from the MPLS region is an encapsulated header in the form of an MPLS packet. In the drawing, reference numeral 130 denotes a matching unit for transmitting and receiving a label information table from the device manager and information required for the lookup apparatus.

The information control process delivered by the IP lookup control apparatus 100 to the lookup performing apparatus 110 is as follows.

Upon receiving the input packet header information, the look-up control apparatus 100 checks the packet type and, in the case of a packet having an MPLS label inserted therein, transfers label information to the MPLS label comparator 111, and the MPLS label comparator 111. The corresponding entry index passed from is fetched to obtain corresponding information from the label information table 120. On the other hand, if the packet is not an MPLS-labeled packet and PPP or RFC1483 type information is inserted, the layer 4 lookup unit 112 and the layer 3 lookup unit are simultaneously extracted by extracting information corresponding to layer 4 and information corresponding to layer 3. 113). If there is a match result from the layer 4 lookup unit 112, the result of the layer 3 lookup unit 113 is not referred to, and the information of the label information table 120 is referred to by referring to the index of the layer 4 lookup unit 112. Fetch However, if a matched entry of the layer 4 lookup unit 112 does not exist, the corresponding information of the label information table 120 is fetched by referring to the matched index of the layer 3 lookup unit 113.

Conventionally, a sequential method of performing a layer 4 lookup first and performing a layer 3 lookup when there is no match is used. However, in the present invention, the layer 4 lookup unit and the layer 3 lookup unit are simultaneously executed using a hardware control technique. By doing so, the lookup process can be performed at a higher speed.

2 shows detailed formats of a header for each packet type transmitted and received to the IP lookup control apparatus 100.

In the figure, 201 shows packet header data transmitted / received to the lookup controller, and the first 4 bytes have channel information, packet type information, and address offset of the IP packet, and the second area has a length corresponding to the packet type. There are other various types of embedded information areas, and the third area represents an IP header area. Reference numeral 202 denotes packet information composed of 4 bytes and includes channel identifier information, packet type, and address offset information. 203, 204, and 205 indicate data information to be inserted for each packet type, and their lengths differ for each packet type. It then contains packet header information for each protocol. 203 indicates data information inserted into LLCs, NLPIDs, and PIDs when an IP packet is delivered on the PPP protocol, and consists of 6 bytes. 204 denotes data information inserted into LLC, SNAP, and PIDs when an IP packet is delivered in the form of an RFC1483 frame, and is composed of 10 bytes. 205 denotes data information inserted into label information, CoS, S, and TTL when the IP packet is transmitted to the MPLS protocol flowing from the MPLS region. When the stack is n, the 205 indicates the top stack indication (S = 1). Four bytes of insert data information for the lower stack are contiguous. 206 represents IP header data information, and consists of a destination address, a source address, and optional areas, including a version, header length, service type, and the like, and has an area of 24 bytes.

3 is a functional block diagram of an IP lookup control apparatus according to the present invention.

The IP lookup controller includes an IP packet header receiver 301, an IP packet header inspector 302, an IP header / label extractor 303, an IP packet header inspector 304, a lookup data / control signal generator 306, CPU matching and arbitration unit 305, lookup performing unit matching unit 307, label information (LIB) matching unit 306, label information (LIB) storage unit 309, transmission header change and alignment unit 310, An IP packet header transmitter 311 is included.

The IP packet header receiving unit 301 receives 32-bit data as a function of receiving a packet header area including packet information and IP header information of an IP packet. The IP packet header checker 302 functions to recognize a packet type, ie, PPP, RFC1483, MPLS packet, etc. among the packet information. The IP header and label extractor 303 recognizes an IP header region starting according to the packet header type and extracts an IP header or an MPLS label. The IP packet header checker 304 performs a check function such as an IP version and a checksum included in the IP header. The lookup data / control signal generator 306 controls the control signal for performing the lookup, the IP destination address, and the source address. The lookup performing apparatus matching unit 307 provides a matching function with the lookup performing apparatus. The label information LIB matching unit 308 fetches the label information LIB from the label information table with reference to the index received from the lookup performing apparatus and stores the label information LIB in the label information LIB storage unit 309. This fetch and save is done directly in hardware without CPU intervention, so the lookup result data can be fetched faster.

The transmission header change and alignment unit 310 extracts information such as TOS, TTL, label information, channel identifier, transmission packet type, and the like from the stored label information LIB and rearranges the header according to the header format of the transmission packet. At this time, the IP header checksum for the changed IP header is recalculated. As the packet type is changed, the length of the packet type information field inserted before the IP header is changed. The offset is calculated by hardware and inserted into the area. The offset is simply calculated using a comparator.

4 is a diagram illustrating a length offset value generation structure and an output value table for explaining the transmission header change and alignment unit 310 in more detail. This generates a length offset value generated using the comparator 401. . 402 denotes a predetermined value for each packet type, and 403 denotes an offset value for packet length between transmission and reception service types. If the value is greater than 0 with reference to the packet length, the packet header length is increased. If the value is smaller than 0, the packet header length is reduced. Therefore, when the packet header part is changed and stored in the packet memory again, if the offset is larger than 0, the start address where the packet is stored moves forward, and when the packet header part is smaller than 0, the start address where the packet is stored has moved backward. .

The IP packet header transmitter 311 transmits the aligned data in synchronization with the transmission clock.

5 is a flowchart illustrating a packet processing for explaining the operation of the IP lookup control apparatus according to the present invention.

When the IP packet header information arrives, the IP packet header receiving unit 301 of the lookup control device stores the packet header area in 32-bit registers, and shifts the received data in synchronization with the reception clock until the entire header information is received. . The first IP packet header checker 302 extracts a packet type region of the packet head information stored by the IP packet header receiver, and extracts an actual IP header region. The second IP packet header checker 304 extracts and checks a TTL, a version, a checksum, and the like in the IP header, respectively. As a result of the inspection by the second IP packet header inspecting unit 304, an error status information flag is set to prevent the lookup process from proceeding with respect to the header in which the error occurs. However, if there is no error, the lookup data / control signal generator 306 may control the control signal and IP header / label extractor for hardware lookup control based on the content address memory (CAM) through the lookup apparatus matching unit 307. The IP address extracted by 303 is transferred to the lookup performing device. The label information matching unit 308 latches the index address from the result of the lookup, fetches corresponding information in the label information table with reference to the index address, and stores the index information in the label information storage unit 309. The transmission header change and alignment unit 310 analyzes a channel identifier, a transmission packet type, and label information from the label information stored in the label information storage unit 309 to generate packet type information inserted from the transmission packet type. Generates a value for the length offset that changes from the transmit packet type and the receive packet type. Here, the TTL, checksum value, etc. are recalculated to rearrange the transmission packet header. The IP packet header transmitter 311 then transmits the IP packet header arranged by the transmitter header change and alignment unit 310.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

According to the present invention made as described above, the CPU is involved in various packet types in the MPLS network to recognize and analyze in hardware without searching the inserted form of the PPP, RFC1483, MPLS label, and the control signal and data to the lookup performer It can increase the speed of IP packet forwarding to improve performance.

Claims (6)

In the look-up control apparatus of the Internet Protocol (IP) packet in the edge router of a multi-protocol label switching (MPLS) network comprising a look-up device and a label information table, Receiving and processing means for receiving an Internet Protocol packet header, checking the type and error of the packet, and extracting a header and a label of the received packet according to the type of the analyzed packet; Lookup data / control signal generating means for receiving an IP header and an error presence signal from the receiving and processing means and providing a control signal and an IP address for performing a lookup to the lookup performing apparatus; Label information fetching means for receiving an index as a result of performing a lookup from the lookup performing apparatus, fetching and storing label information corresponding to the index from the label information table; And Header sorting and transmitting means for extracting various kinds of information from the label information stored by the label information fetching means, rearranging the information according to the header format of the transmission packet, and inserting and inserting checksum information and offset for the new header. Device for lookup control of Internet Protocol (IP) packet in the edge router of a multi-protocol label switching (MPLS) network comprising a. The method of claim 1, And a lookup performer matching means for matching with the lookup performer. 10. A lookup control apparatus for an Internet Protocol (IP) packet in an edge router of a multiprotocol label switching (MPLS) network. The method according to claim 1 or 2, Receiving and processing means of the packet header, Packet header receiving means for receiving Internet protocol packet information and a header area; First packet header checking means for checking a type of a packet header input from the packet header receiving means; Second packet header checking means for checking a version and a checksum included in the received packet header to confirm an error; And Header / label extraction means for recognizing a header area starting from a type of a packet identified by said first packet header checking means, and extracting an Internet protocol header or label Device for lookup control of the Internet Protocol (IP) packet in the edge router of the multi-protocol label switching (MPLS) network comprising a. The method of claim 3, wherein The packet header receiving means, Internet Protocol (IP) packet in edge router of multiprotocol label switching (MPLS) network, including shift register, shifting and storing received data in synchronization with reception clock until full header information is received Lookup control device. The method of claim 3, wherein The label information fetch means, Label information matching means for fetching corresponding label information from the label information table using an index transmitted from the look-up performing apparatus through the look-up performing apparatus matching means; And Label information storage means for temporarily storing label information fetched by the label information matching means Device for lookup control of the Internet Protocol (IP) packet in the edge router of the multi-protocol label switching (MPLS) network comprising a. The method of claim 5, The header alignment and transmission means, Extract TOS, TTL, label information, channel identifier, and type information of the transmission packet from the label information stored in the label information storage means, and rearrange them according to the header format of the transmission packet, wherein the header checksum for the changed header is calculated. Transmission header change and alignment means for inserting the data into the packet type information area and inserting the data into the packet type information area according to the packet type; And Transmitting means for transmitting the header aligned by the transmitting header changing and sorting means in synchronization with a transmitting clock; Device for lookup control of the Internet Protocol (IP) packet in the edge router of the multi-protocol label switching (MPLS) network comprising a.