Systems and methods for generating IPID across a cluster network
In a cluster environment, nodes participating in the cluster may generate packets with the same source IP to the same destination IP. If those packets get fragmented down stream, then reassembling this packets depends on the source IP, destination IP, protocol and the IP identifier field (IPID) of the IP packet. As the source IP, destination IP and protocol may be fixed, the IPID generation is coordinated across the nodes to support reassembly down stream and avoid tuple collision. The IPID space may be equally split among the nodes in the cluster. Each node generates IPID within its range to avoid a collision with an IPID generated from another node.
1. A method of generating Internet Protocol (IP) identifiers across a cluster of intermediary devices, the method comprising:
(a) establishing for a cluster of intermediary devices, a range of internet protocol (IP) identifiers (IPIDs) to be allocated among each intermediary device in the cluster, the range of IPIDs comprising values to be identified in an IP identifier (IPID) field in an IP layer of packets transmitted from the cluster;
(b) allocating to each intermediary device a subrange of IPIDs in the range of IPIDs;
(c) generating, by a first intermediary device of the cluster, an IPID within the subrange of IPIDs allocated to the first intermediary device; and
(d) transmitting, by the first intermediary device, the packet having the IPID field in the IP layer of the packet set to the IPID, the IPID field in the IP layer used for reassembly of fragmented packets.
2. The method of claim 1 , wherein step (a) further comprises establishing the range of IPIDS to comprise unique non-overlapping values to be identified in the IPID field of an IP layer of transport layer packets transmitted from the cluster.
3. The method of claim 1 , wherein step (b) further comprises allocating, by a master intermediary device of the cluster, the range of IPIDs evenly among each of the intermediary devices of the cluster.
4. The method of claim 1 , wherein step (b) further comprises allocating, by each intermediary device of the cluster, a corresponding subrange of IPIDs from the range of IPIDs.
5. The method of claim 1 , wherein step (c) further comprises generating, by the first intermediary device, the IPID by selecting a next available IPID in the subrange of IPIDs.
6. The method of claim 1 , wherein step (c) further comprises generating, by the first intermediary device, the IPID by reusing a previously used IPID in the subrange of IPIDs that is currently available.
7. The method of claim 1 , wherein step (d) further comprises setting, by the first intermediary device, the IPID field of an IP layer of the packet to the generated IPID.
8. The method of claim 1 , further comprising determining, by the first intermediary device, that at least one of a source IP address, destination IP address or a protocol field of an IP layer of a second packet to be transmitted from the first intermediary device differs from the source IP address, destination IP address or the protocol field of the IP layer of the packet.
9. The method of claim 8 , further comprising selecting, by the first intermediary device responsive to the determination, the same IPID of the packet as the IPID of the second packet.
10. The method of claim 1 , further comprising determining, by the first intermediary device, that a source IP address, destination IP address and a protocol field of an IP layer of a second packet to be transmitted from the first intermediary device is the same as the source IP address, destination IP address as the protocol field of the IP layer of the packet and generating for the second packet a second IPID from the subrange of IPIDs different from the IPID of the first packet.
11. A system for handling fragmented packets distributed across intermediary devices of a cluster, the system comprising:
a cluster of a plurality of intermediary devices;
a range of internet protocol (IP) identifiers (IPIDs) to be allocated among each intermediary device in the cluster, the range of IPIDs comprising values to be identified in an IP identifier (IPID) field in an IP layer of packets transmitted from the cluster;
each intermediary device of the cluster receiving an allocation of a subrange of IPIDs in the range of IPIDs; and
wherein a first intermediary device of the cluster generates an IPID within the
subrange of IPIDs allocated to the first intermediary device and transmits the packet having the IPID field in the IP layer of the packet set to the IPID, the IPID field in the IP layer used for reassembly of fragmented packets.
12. The system of claim 11 , wherein the range of IPIDs comprise unique non-overlapping values to be identified in the IPID field of an IP layer of transport layer packets transmitted from the cluster.
13. The system of claim 11 , wherein a master intermediary device of the cluster allocates the range of IPIDs evenly among each of the intermediary devices of the cluster.
14. The system of claim 11 , wherein each intermediary device of the cluster allocated a corresponding subrange of IPIDs from the range of IPIDs.
15. The system of claim 11 , wherein the first intermediary device generates the IPID by selecting a next available IPID in the subrange of IPIDs.
16. The system of claim 11 , wherein the first intermediary device generates the IPID by reusing a previously used IPID in the subrange of IPIDs that is currently available.
17. The system of claim 11 , wherein the first intermediary device sets the IPID field of an IP layer of the packet to the generated IPID.
18. The system of claim 11 , wherein the first intermediary device determines that at least one of a source IP address, destination IP address or a protocol field of an IP layer of a second packet to be transmitted from the first intermediary device differs from the source IP address, destination IP address or the protocol field of the IP layer of the packet.
19. The system of claim 18 , wherein the first intermediary device selects, responsive to the determination, the same IPID of the packet as the IPID of the second packet.
20. The system of claim 11 , wherein the first intermediary device determines that a source IP address, destination IP address and a protocol field of an IP layer of a second packet to be transmitted from the first intermediary device is the same as the source IP address, destination IP address as the protocol field of the IP layer of the packet and generates for the second packet a second IPID from the subrange of IPIDs different from the IPID of the first packet.