Method and apparatus for integrating routing and bridging functions

• US 7,856,024 B1
• Filed: 12/12/2008
• Issued: 12/21/2010
• Est. Priority Date: 12/12/2008
• Status: Active Grant

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs San Jose, Inc. (Infinera Corp.)
• Inventors: Nubani, Samer Isam, Rajagopalan, Balaji, Karuppiah, Anuradha
• Primary Examiner(s): Vu; Thong H
• Application Number:
  US12/333,609
• Time in Patent Office: 739 Days
• Field of Search: 370/390, 370/389, 370/230, 370/392, 370/395, 370/356, 370/469, 370/401, 709/224, 709/236, 709/229, 709/245
• US Class Current: 370/401
• CPC Class Codes: H04L 49/604 Hybrid IP/Ethernet switches
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Abstract

An apparatus and method for routing data packets between a routed network and a local bridged network using integrated routing and bridging (“IRB”) functions are disclosed. In one embodiment a bridge interface between a host in the local bridge network and a bridging engine is IRB enabled. An unnumbered Internet Protocol (“IP”) interface is then added between the host and a routing engine in accordance with the IRB enabled bridge interface. Subsequently packets received from the routed network are forwarded directly by the routing engine to the host in the local bridge network via the unnumbered IP interface, thereby bypassing the bridging engine. Through use of an embodiment of the present invention, packet processing delay in each network device is reduced (because of bypassing the bridging engine), thereby decreasing packet latency in an ever growing network.

Claims

1. A method for data transfer between a routed network and a bridge network, comprising:

identifying a first bridge interface that has been integrated routing and bridging (“

IRB”

) enabled bridge interface between a first host in a local bridge network and a bridging engine;

adding a first unnumbered internet Protocol (“

IP”

) interface between the first host and a routing engine in accordance with the first bridge interface; and

forwarding packets directly by the routing engine from the routing engine to the first host via the first unnumbered IP interface.

2. The method of claim 1, further comprising:

receiving an initial IP packet from a routed network to be transmitted to the first host;

searching an IP route table to identify the IRB interface in accordance with a destination IP address stored in a header of the initial IP packet;

identifying a Media Access Control (“

MAC”

) address for the first host by searching an Address Resolution Protocol (“

ARP”

) table;

obtaining an ARP response via the first unnumbered IP interface from the first host; and

modifying the IP route table and ARP table based on the ARP response.

3. The method of claim 2, wherein obtaining an ARP response includes broadcasting an ARP request over all the bridge interfaces associate with the RB interface on not finding a valid ARP entry corresponding to the first host.

4. The method of claim 2, wherein updating the IP route table includes adding a route entry for the first host with the first unnumbered IP interface as the outgoing interface.

5. The method of claim 2, wherein updating the ARP table includes adding an ARP entry for the first host based on the ARP response.

6. The method of claim 2, wherein encapsulating the packet with the first host'"'"'s hardware address includes searching an ARP table using the destination IP address to identify the first host'"'"'s MAC address.

7. The method of claim 1, further comprising:

receiving a subsequent IP packet from the routed network to be transmitted to the first host;

obtaining the first unnumbered IP interface as the outgoing interface from the IP route table; and

forwarding the packet to the first host after encapsulating the packet with the first host'"'"'s hardware address.

8. The method of claim 1, comprising:

identifying a second bridge interface that has been IRB enabled between a second host in the local bridge network and the bridging engine;

adding a second unnumbered IP interface between the second host and the routing engine in accordance with the second IRB enabled bridge interface; and

forwarding packets directly by the routing engine from the routed network to the second host via the second unnumbered IP interface.

9. The method of claim 1, wherein sending the first IP packet to the first host from the routing engine via the first unnumbered IP interface includes forwarding the first IP packet directly from the routing engine to the first host without going through the bridging engine.

10. A method for routing data, comprising:

receiving an initial Internet Protocol (“

IP”

) packet over a routed network to be transmitted to a first host;

searching a first lookup table to determine a first bridge group in accordance with information stored in a header of the initial IP packet;

searching a second lookup table to identifying a Media Access Control (“

MAC”

) address associated with the first host after obtaining information relating to the first bridge group;

obtaining a first unnumbered IP interface associated to a first bridge interface of the first host; and

storing the first unnumbered IP interface in a new entry of the first lookup table.

11. The method of claim 10, further comprising:

receiving a first IP packet over the routed network to be transmitted to the first host; and

identifying the first unnumbered IP interface for an outgoing interface to reach the first host in accordance with a search result from the first lookup table.

12. The method of claim 11, further comprising:

fetching the MAC address from the second lookup table and encapsulating the MAC address to the first IP packet; and

sending the first IP packet with the encapsulation to the first host from a routing engine via the first unnumbered IP interface.

13. The method of claim 10, further comprising:

receiving a second IP packet over the routed network to be transmitted to the second host; and

identifying a second unnumbered IP interface as an outgoing interface to reach the second host via a search of the first lookup table.

14. The method of claim 10,

wherein searching a first lookup table further includes searching a IP route table to identify the bridge group;

and

wherein searching a second lookup table further includes searching an Address Resolution Protocol (“

ARP”

) table to identifying a MAC address associated with the first host.

15. The method of claim 10, wherein obtaining the first unnumbered IP interface further includes broadcasting an ARP request over all the bridge interfaces in the bridge group and receiving an ARP response from the first host over the first unnumbered IP interface.

16. The method of claim 10, wherein storing the first unnumbered IP interface in a new entry of the first lookup table includes add a route entry for the first host with the first unnumbered IP interface as the outgoing interface.

17. An apparatus of transferring data, comprising:

means for identifying a first integrated routing and bridging (“

IRB”

) enabled bridge interface between a first host and a bridging engine;

means for adding a first unnumbered Internet Protocol (“

IP”

) interface between the first host and a routing engine corresponding to the first IRB enabled bridge interface;

means for encapsulating a first host destination hardware address associated with the first host to a first IP packet; and

means for sending the first IP packet to the first host from the routing engine via the first unnumbered IP interface.

18. The apparatus of claim 17, further comprising:

means for receiving an initial IP packet over a routed network to be transmitted to the first host;

means for searching an IP route table to identify the bridge group in accordance with information stored in a header of the initial IP packet;

means for identifying a Media Access Control (“

MAC”

) address for the first host by performing an Address Resolution Protocol (“

ARP”

) table; and

means for obtaining ARP response via the first unnumbered IP interface from the first host; and

means for modifying the IP route table and ARP table based on the ARP response.

19. The apparatus of claim 17, further comprising:

means for obtaining the first unnumbered IP interface as the outgoing interface from the IP route table; and

means for forwarding the packet to the first host after encapsulating the packet with the first host'"'"'s hardware address.

20. The apparatus of claim 18, wherein means for obtaining an ARP response includes means for broadcasting an ARP request over all the bridge interfaces associate with the RB interface on not finding a valid ARP entry corresponding to the first host.