KR100475436B1 - distributed router and ARP packet processing method thereof - Google Patents

Abstract

The ARP packet processing distributed router according to the present invention includes a forwarding table and an ARP table, and is connected to an arbitrary Ethernet interface and, when an arbitrary ARP packet is received, refers to the forwarding table and the ARP table to a corresponding destination address. And a network processor for forwarding the packet and a host processor for communicating with the network processor to perform a routing function. When the network processor receives any ARP packet, the network processor searches for a forwarding table and an ARP table. If the information about the ARP packet does not exist, the forwarding table and the ARP table are updated with the information contained in the ARP packet, and only if the ARP packet is an ARP response packet, the corresponding ARP packet is transmitted to the host processor to host By updating the routing information of the processor, the conventional route Because of the structure in the ARP packet it is passed to the look-up and fail to de-packet the host processor has the advantage to minimize the overhead generated at the interface between the network processor and the host processor.

Description

Distributed router and ARP packet processing method

The present invention relates to a distributed router and a method for processing an address resolution protocol packet of the distributed router.

In general, in order to provide an Internet service that delivers arbitrary data packets to a destination network using the Internet, information about network topology and network conditions, that is, routing information, is needed. Such routing information is provided by a routing protocol.

Looking at the types of routing protocols, the Address Resolution Protocol (hereinafter referred to as ARP), which is used to map IP addresses to physical network addresses on an IP network, and periodically exchanges routing information with neighboring routers. Routing Information Protocol (RIP) protocol that uses routing vector tables to determine the best route and updates routing information every 30 seconds, and routing information only when there is a change in the actual routing information. OSPF (Open Shortest Path First) protocol for updating.

On the other hand, the distributed router structure is a structure in which a plurality of functionally independent routers form an integrated IP router system, which is more scalable than a centralized router structure.

In such a system, a network processor and a host processor are implemented in each internal router to separate routing protocol functions and IP forwarding functions.

If a system of this structure is connected to an Ethernet interface, the network processor must know the destination MAC address for packet forwarding, and ARP is used to manage the MAC addresses for this purpose.

ARP is a protocol used to map IP addresses to physical network addresses on an IP network. In this case, the physical network address means a 48-bit network card address of Ethernet or Token Ring.

For example, if IP host A does not know the physical network address of IP host B when it wants to send an IP packet to IP host B, an ARP packet with the destination IP address B and the broadcasting physical network address FFFFFFFFFFFF using the ARP protocol. Send it over the network. IP host B responds to A with its physical network address when it receives an ARP packet whose IP address is at its destination.

The IP address and the corresponding physical network address information collected in this way are stored in a table in memory called ARP cache of each IP host and used again in the next packet transmission. Contrary to ARP, if an IP host knows its physical network address but does not know its IP address, it uses RARP (ReverseARP) to request an IP address from a server.

1 is a block diagram illustrating an internal router in a conventional distributed router architecture system. Referring to FIG. 1, in the conventional router 10, all ARP packets entering the micro-engine 12b are delivered to an ARP operating module 11b in the host processor 11 and transferred to an ARP stack therein. Is processed. At this time, in order to properly update the MAC addresses in the forwarding table 12c, the forwarding table 12c is appropriately updated by referring to the information of the ARP packets passing through the network processor application module 12a in the network processor 12.

The reason why ARP packets should be delivered to the host processor 11 is that the routing protocol daemons in other routers to which routing protocol daemon modules 11a operating in the host processor 11 are connected via Ethernet are connected. This is because it is used when you need to send and receive routing information.

On the other hand, in the conventional distributed router system, the ARP operation module 11b of the host processor 11 is responsible for processing a lookup failed packet.

The lookup failed packet refers to a packet that has failed to find an output port or find a destination MAC address as a result of the micro engine 12b searching the forwarding table 12c to forward the input IP packet. .

That is, when the lookup failed packet is delivered to the host processor 11, the IP stack in the host processor 11 searches the routing table again to forward the packet.

However, since the routing table in the host processor 11 and the forwarding table 12c in the network processor 12 always maintain the same information, the lookup fails even at this time, so that an appropriate Internet Control Message Protocol (ICMP) error packet is generated. It generates a packet and forwards it to the host or router that sent it.

In the system of the conventional distributed router structure as described above, all incoming ARP packets and lookup failed packets are delivered to the host processor 11, so that the performance of the interface between the network processor 12 and the host processor 11 is improved. Will fall.

Therefore, the efficiency of updating the forwarding table 12c of the network processor 12 by the host processor 11 becomes poor. In this case, there is a problem that the micro engine 12b does not normally forward IP packets.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is a distributed router that can efficiently process ARP packets in a distributed router architecture system and normally perform IP packet forwarding for packets that fail IP forwarding, and a distributed router. Its purpose is to provide a method for processing ARP packets in a distributed router.

According to an aspect of the present invention for achieving this object, provided with a forwarding table and an ARP table, connected to any Ethernet interface, if any ARP packet is received, the destination by referring to the forwarding table and the ARP table And a network processor for forwarding a corresponding packet to an address, and a host processor for performing a routing function by communicating with the network processor, wherein the network processor searches for a forwarding table and an ARP table when an arbitrary ARP packet is received. If the information about the ARP packet does not exist, the forwarding table and the ARP table are updated with the information included in the ARP packet, and the corresponding ARP packet is transmitted to the host processor only if the ARP packet is an ARP response packet. Packet to update the routing information of the host processor Provides a distributed router for processing.

In addition, according to another aspect of the present invention, provided with a forwarding table and an ARP table, connected to any Ethernet interface, if any ARP packet is received, the packet to the corresponding destination address with reference to the forwarding table and the ARP table A method for processing arbitrary ARP packets in a distributed router comprising a network processor forwarding a network processor and a host processor communicating with the network processor to perform a routing function, the network processor receiving any ARP packets Searching the forwarding table and the ARP table, and updating the forwarding table and the ARP table with the information included in the ARP packet when the information about the corresponding ARP packet does not exist in the search result, the forwarding table, and the ARP table. And determining whether the corresponding ARP packet is an ARP response packet. For example, in the case of an ARP response packet, a method for processing an ARP packet of a distributed router that transmits the corresponding ARP packet to a host processor and updates routing information of the host processor is provided.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

2 is a block diagram illustrating a distributed router according to an embodiment of the present invention.

Referring to FIG. 2, the distributed router according to the present invention includes a forwarding table 125 and an ARP table 126 and is connected to an arbitrary Ethernet interface, and when an arbitrary ARP packet is received, the forwarding table ( 125) and a network processor 120 for forwarding the packet to the corresponding destination address with reference to the ARP table 126, and a host processor 110 communicating with the network processor 120 to perform a routing function. Is done.

When any ARP packet is received, the network processor 120 searches the forwarding table 125 and the ARP table 126 and, if information about the ARP packet does not exist, includes the information included in the ARP packet. The monitoring table 125 and the ARP table 126 are updated, and only when the corresponding ARP packet is an ARP response packet, the corresponding ARP packet is transmitted to the host processor 110 to update the routing information of the host processor 110.

The network processor 120 according to the present invention includes a micro engine 121, a lookup failed packet manager 122, an ARP table manager 123, and a forwarding table manager 124. 125 and an ARP table 126.

When any ARP packet is received, the micro engine 121 performs forwarding with reference to the forwarding table 125 and the ARP table 126, and when a lookup fail packet occurs, a lookup fail occurs in the packet. The reason is indicated and sent to the lookup failed packet manager 122.

The lookup failed packet manager 122 generates and transmits an ICMP error message corresponding to the reason why the lookup fail indicated by the micro engine 121 occurs.

That is, the lookup failed packet information transmitted from the micro engine 121 indicates the reason why the packet fails to lookup and is transmitted. Accordingly, the lookup failed packet manager 122 generates appropriate ICMP error packets according to the contents displayed by the micro engine 121 and transmits them to the micro engine 121. In addition, the lookup failed packet is not transmitted to the host processor 110. Accordingly, in the related art, it is possible to solve a decrease in the efficiency of processing generated by transmitting the lookup failed packet to the host processor.

The ARP table manager 123 manages the ARP table 126 according to the packet input through the micro engine 121. In this case, the information stored in the ARP table 126 includes IP address, MAC address, and time related information.

That is, when ARP packets input through the micro engine 121 are delivered to the ARP table manager 123, the ARP table manager 123 may be configured with a source IP address in the input packet ARP request / reply. MAC address information is stored in the ARP table 126. In addition, the ARP table manager 123 performs a general ARP processing function (RFC 826). Accordingly, when forwarding the packet, the micro engine 121 refers to this ARP table together with the forwarding table 125.

In addition, the ARP table manager 123 determines whether the input packet is an ARP response packet and delivers the packet to the host processor 110 only when the packet is an ARP packet. The packet is transmitted to the host processor 110 in the case of the ARP response packet because the packet may be an ARP response packet to the ARP request packet sent by the host processor 110.

The forwarding table manager 124 stores the destination IP address, IP subnet mask address, next hop IP address, and output port information of the packet in the packet input through the micro engine 121, Each time a packet is received, the forwarding table 125 is updated accordingly.

The forwarding table 125 is controlled by the forwarding table manager 124 to store destination IP addresses, IP subnet mask addresses, next hop IP addresses, and output port information of the packets for any packets. This information stored in the forwarding table 125 is used as a reference for forwarding packets in the micro engine 121.

 The ARP table 126 is controlled by the ARP table manager 123 and stores IP address, MAC address, and time related information for any packet. This information stored in the ARP table 126 is used for the processing of ARP packets in the micro engine 121.

3 is a flowchart illustrating a process of processing ARP packets in a distributed router according to the present invention.

Referring to FIG. 3, when arbitrary ARP packets are received by the micro engine 121, the micro engine 121 transmits the received packets to the ARP table manager 123 and the forwarding table manager 124 to forward the corresponding packets. The table 125 and the ARP table 126 are searched for (S1). If there is related information in the search result forwarding table 125 and the ARP table 126, the micro engine 121 performs forwarding with reference to the information of the forwarding table 125 and the ARP table 126 (S12).

If the forwarding table 125 and the ARP table 126 do not have related information about the packet, the forwarding table manager 124 updates the forwarding table 125 with the information included in the packet, and the ARP table manager 123 updates the ARP table 126 (S4).

That is, the ARP table manager 123 stores the source IP address and the MAC address information in the input packet ARP request / reply in the ARP table 126. The forwarding table manager 124 stores the destination IP address, the IP subnet mask address, the next hop IP address, and the output port information of the packet in the forwarding table 125.

Next, the ARP table manager 123 determines whether the input packet is an ARP response packet (S5). If the received packet is an ARP packet and an ARP response packet, the packet is transmitted to the host processor 110 (S6). If the received packet is not an ARP response packet, the packet is not transmitted to the host processor 110.

4 is a flowchart illustrating a process of processing a lookup failed packet in a distributed router according to the present invention.

Referring to FIG. 4, the micro-engine 121 determines whether a lookup failed packet has occurred (S11). If a random lookup failed packet occurs, the micro engine 121 displays the reason why the lookup failed in the corresponding packet and displays the lookup failed packet. It transmits to the manager 122 (S12).

The lookup failed packet manager 122 generates an ICMP error message packet corresponding to the reason why the lookup indicated in the packet by the micro engine 121 fails, and transmits the ICMP error message packet to the micro engine 121 to host the processing of the lookup failed packet. It can be processed in the network processor 120 without transmitting to the processor (110).

According to the present invention, since the ARP packets and the lookup failed packets are delivered to the host processor in the conventional router structure, a problem of overhead occurring at the interface between the network processor and the host processor may be minimized.

That is, instead of sending all ARP packets to the host processor, the network processor sends only the ARP response packet to the host processor and processes other packets within the network processor, thereby providing an interface between the host processor and the network processor. As the load is reduced, the speed of forwarding table updates in the network processor implemented in the router can be increased.

1 is a block diagram of an internal router configuration of a conventional distributed router system.

Figure 2 is a block diagram of the internal router configuration of a distributed router system according to the present invention.

3 is a flowchart illustrating a process of processing ARP packets in a distributed router according to the present invention.

4 is a flowchart illustrating a process of processing a lookup failed packet in a distributed router according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: distributed router 110: host processor

111: routing protocol daemon module 112: ARP operation module

120: network processor 121: micro-engine

122: Lookup Failed Packet Manager 123: ARP Table Manager

124: Forwarding Table Manager 125: Forwarding Table

Claims (6)

A network processor having a forwarding table and an ARP table, connected to an arbitrary Ethernet interface, and forwarding the packet to a corresponding destination address with reference to the forwarding table and the ARP table when an ARP packet is received; Comprising a host processor for performing a routing function by communicating with the network processor, When an ARP packet is received, the network processor searches the forwarding table and the ARP table, and if the information about the ARP packet does not exist, the network processor uses the information included in the ARP packet as the forwarding table and the ARP table. And update the routing information of the host processor by transmitting the corresponding ARP packet to the host processor only if the corresponding ARP packet is an ARP response packet. The method of claim 1, wherein the network processor, A micro-engine that performs forwarding with reference to the forwarding table and the ARP table when a random ARP packet is received, and displays a reason why a lookup fail occurs in the packet when a lookup fail packet occurs; A forwarding table manager managing the forwarding table information according to the packet input through the micro engine; An ARP table manager managing the ARP table information according to the packet input through the micro-engine, and transmitting the packet to the host processor only when the input packet is an ARP response packet; And a lookup failed packet manager for generating an ICMP error message corresponding to the reason why the lookup failure indicated by the micro engine has occurred and storing the same in the ARP table. The method of claim 2, wherein the forwarding table, ARP packet processing distributed router including destination IP address, IP subnet mask address, next hop IP address, and output port information. The method of claim 2, wherein the ARP table, ARP packet processing distributed router that stores IP address, MAC address, and time related information. A network processor having a forwarding table and an ARP table, connected to an arbitrary Ethernet interface, and forwarding the packet to a corresponding destination address with reference to the forwarding table and the ARP table when an ARP packet is received; In the method for processing any ARP packet in a distributed router comprising a host processor for performing a routing function by communicating with the processor, Retrieving the forwarding table and the ARP table when any ARP packet is received at the network processor; If there is no information on the corresponding ARP packet in the forwarding table and the ARP table, updating the forwarding table and the ARP table with information included in the corresponding ARP packet; Determining whether the ARP packet is an ARP response packet, if the ARP response packet, and transmitting the ARP packet to the host processor to update the routing information of the host processor ARP packet processing method of the distributed router . 6. The distributed router of claim 5, wherein when a lookup fail packet is generated in the network processor, the reason why the lookup fail occurs in the packet is generated, and accordingly, generating an ICMP error packet. ARP packet processing method.