System and method for hardware-based learning of internet protocol addresses in a network environment
A method is provided one example embodiment and includes receiving a packet including a source /32 address and a destination /32 address. The source /32 address can indicate an Internet Protocol (IP) address of a source host that sent the packet. The destination /32 address can indicate an IP address of a destination host to which the packet is destined. The method may also include looking up the destination /32 address and the source /32 address in a Forwarding Information Base/adjacency (FIB)/(ADJ) table implemented in a hardware of a leaf switch in a network. Additionally, the method may include adding the source /32 address and corresponding adjacency information to the FIB/ADJ table if the destination /32 address is found in the FIB/ADJ table, and the source /32 address is not found in the FIB/ADJ table. The method may also include forwarding the packet to the destination host.
1. A method, comprising:
receiving a packet at a leaf switch in a network, the packet including a source address and a destination address, wherein the source address indicates an Internet Protocol (IP) address of a source host that sent the packet, wherein the destination address indicates an IP address of a destination host to which the packet is destined, wherein when a destination Media Access Control (DMAC) address of the packet is a MAC address of the leaf switch, the method further comprises:
looking up the destination address and the source address in a Forwarding Information Base/adjacency (FIB)/(ADJ) table implemented in a hardware of the leaf switch;
adding the source address and corresponding adjacency information to the FIB/ADJ table when the destination address is found in the FIB/ADJ table and the source address is not found in the FIB/ADJ table; and
forwarding the packet to the destination host, wherein the source address and the destination address are 32 bit IP version 4 addresses.
2. The method of claim 1 , further comprising:
dropping the packet when the destination address and the source address are not found in the FIB/ADJ table.
3. The method of claim 1 , further comprising:
looking up a destination subnet having a subnet prefix corresponding to the destination address; and
multicasting the packet to the destination subnet when the destination address is not found in the FIB/ADJ table and the source address is found in the FIB/ADJ table.
4. The method of claim 1 , further comprising:
configuring subnet prefixes of subnets in the network in the FIB/ADJ table.
5. The method of claim 1 , further comprising:
installing addresses of hosts connected to the leaf switch.
6. The method of claim 1 , further comprising:
setting a learnt bit in the FIB/ADJ table when the source address is added; and
resetting a corresponding hit bit when the destination address or the source address is found in the FIB/ADJ table.
7. The method of claim 6 , further comprising:
deleting an entry in the FIB/ADJ table corresponding to the destination address and the source address according to an aging criterion.
8. The method of claim 7 , wherein the aging criterion is a predetermined time interval.
9. The method of claim 7 , wherein the aging criterion is a predetermined threshold level of free space allocated to the FIB/ADJ table.
10. The method of claim 1 , wherein the source address is learnt on leaf switches that are part of a Distributed Ether Channel (DEC), through which a destination dual-homed server is reached.
11. A non-transitory computer readable medium that includes instructions for execution and when executed by a processor of a leaf switch in a network, is configured to perform operations comprising:
receiving a packet including a source /32 address and a destination address, wherein the source address indicates an Internet Protocol (IP) address of a source host that sent the packet, wherein the destination address indicates an IP address of a destination host to which the packet is destined, wherein when a destination Media Access Control (DMAC) address of the packet is a MAC address of the leaf switch, the operations further comprises:
looking up the destination address and the source address in a Forwarding Information Base/adjacency (FIB)/(ADJ) table implemented in a hardware of the leaf switch;
adding the source address and corresponding adjacency information to the FIB/ADJ table when the destination address is found in the FIB/ADJ table and the source address is not found in the FIB/ADJ table; and
forwarding the packet to the destination host, wherein the source address and the destination address are 32 bit IP version 4 addresses.
12. The non-transitory computer readable medium of claim 11 , the operations further comprising:
dropping the packet when the destination address and the source address are not found in the FIB/ADJ table.
13. The non-transitory computer readable medium of claim 11 , the operations further comprising:
looking up a destination subnet having a subnet prefix corresponding to the destination address; and
multicasting the packet to the destination subnet when the destination address is not found in the FIB/ADJ table and the source address is found in the FIB/ADJ table.
14. The non-transitory computer readable medium of claim 11 , the operations further comprising:
configuring subnet prefixes of subnets in the network in the FIB/ADJ table.
15. The non-transitory computer readable medium of claim 11 , the operations further comprising:
installing addresses of hosts connected to the leaf switch.
16. An apparatus, comprising:
a memory element for storing data; and
a processor configured to execute instructions associated with the data, wherein the processor and the memory element cooperate, such that the apparatus is configured as a leaf switch for:
receiving a packet including a source address and a destination address, wherein the source address indicates an Internet Protocol (IP) address of a source host that sent the packet, wherein the destination address indicates an IP address of a destination host to which the packet is destined, wherein when a destination Media Access Control (DMAC) address of the packet is a MAC address of the apparatus, the apparatus is further configured for:
looking up the destination address and the source address in a Forwarding Information Base/adjacency (FIB)/(ADJ) table implemented in a hardware of the apparatus;
adding the source address and corresponding adjacency information to the FIB/ADJ table when the destination address is found in the FIB/ADJ table and the source address is not found in the FIB/ADJ table; and
forwarding the packet to the destination host, wherein the source address and the destination address are 32 bit IP version 4 addresses.
17. The apparatus of claim 16 , further configured for:
dropping the packet when the destination address and the source address are not found in the FIB/ADJ table.
18. The apparatus of claim 16 , further configured for:
looking up a destination subnet having a subnet prefix corresponding to the destination address; and
multicasting the packet to the destination subnet when the destination address is not found in the FIB/ADJ table and the source address is found in the FIB/ADJ table.
19. The apparatus of claim 16 , further configured for:
configuring subnet prefixes of subnets in the network in the FIB/ADJ table.
20. The apparatus of claim 16 , further configured for:
installing addresses of hosts connected to the apparatus.