AIA enhancements to support L2 connected networks

• US 10,038,632 B2
• Filed: 07/23/2015
• Issued: 07/31/2018
• Est. Priority Date: 07/23/2015
• Status: Active Grant

• Current Assignee: NetScout Systems Incorporated
• Original Assignee: NetScout Systems Incorporated
• Inventors: Vinsel, Peter C., Naing, Win
• Primary Examiner(s): Nowlin, Eric
• Application Number:
  US14/807,524
• Publication Number:
  US 20170026287A1
• Time in Patent Office: 1,104 Days
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/66 Layer 2 routing, e.g. in Ethernet based MAN's

Abstract

A method for determining a routing for packets aggregated from multiple Layer 2 (L2) networks is provided. An ingress packet is received from an ingress inline network port and is processed to extract a source Media Access Control (MAC) address and a port identifier associated with the source MAC address. The extracted source MAC address of the ingress packet is looked up in a MAC address table. The ingress packet is forwarded to an inline tool device. When an egress packet is received back from the inline tool device it is processed to extract source and destination MAC addresses. The extracted source and destination MAC addresses of the egress packet are looked up in the MAC address table. The egress packet is transmitted to an egress inline port based on the looked up destination MAC address.

Claims

1. A method for determining a routing for packets, the method comprising:

coupling with one or more inline tool devices and a plurality of networks, two or more of the networks of the plurality of networks having a Layer 2 (L2) connection between the two or more networks of the plurality of networks, the L2 connection providing for communication between the two or more networks of the plurality of networks;

processing an ingress packet received from an ingress inline network port to extract a source Media Access Control (MAC) address and a port identifier associated with the source MAC address;

looking up the extracted source MAC address of the ingress packet in a MAC address table;

forwarding the ingress packet to the one or more inline tool devices;

processing an egress packet received from the one or more inline tool devices to extract at least one of a source MAC address and a destination MAC address;

looking up the extracted source MAC address of the egress packet in the MAC address table;

detecting whether there is an L2 connection based on finding the MAC source address in the MAC address table; and

transmitting the egress packet to an egress inline network port, the egress inline network port being selected based on whether the L2 connection was detected and at least one of the looked up source MAC address and the extracted destination MAC address of the egress packet.

2. The method of claim 1, wherein the MAC address table comprises a memory array storing table entries, the table entries each comprising a MAC address selected from at least one of a source MAC address and a destination MAC address and a port identifier that identifies an ingress inline network port or egress inline network port associated with the MAC address.

3. The method of claim 1, wherein looking up the extracted source MAC address of the ingress packet in a MAC address table further comprises determining whether the extracted source MAC address of the ingress packet is found in the MAC address table and creating a new entry in response to determining that the extracted source MAC address of the ingress packet is not found in the MAC address table, wherein the new entry comprises the extracted source MAC address of the ingress packet and the extracted port identifier associated with the extracted source MAC address.

4. The method of claim 3, wherein determining whether the extracted source MAC address of the ingress packet is found in the MAC address table further comprises determining whether the extracted port identifier associated with the extracted source MAC address of the ingress packet matches a port identifier associated with the MAC address found in the MAC address table and creating a new entry in response to determining that the extracted port identifier does not match the port identifier associated with the MAC address found in the MAC address table, wherein the new entry comprises the extracted source MAC address of the ingress packet and the extracted port identifier associated with the extracted source MAC address of the ingress packet.

5. The method of claim 1, further comprising looking up the extracted destination MAC address of the egress packet in the MAC address table t.

6. The method of claim 5, wherein looking up the extracted source MAC address of the egress packet in the MAC address table further comprises:

determining whether a single entry matching the extracted source MAC address of the egress packet is found in the MAC address table; and

selecting the port identifier associated with the MAC address found in the MAC address table as the egress port for the egress packet, responsive to finding the single entry.

7. The method of claim 5, wherein looking up the extracted destination MAC address of the egress packet further comprises determining whether the extracted destination MAC address belongs to a multicast packet.

8. The method of claim 5, wherein looking up the extracted destination MAC address of the egress packet in the MAC address table further comprises:

determining whether a single entry or multiple entries matching the extracted destination MAC address of the egress packet is found in the MAC address table;

if so, selecting the single entry found or an entry of the multiple entries that was most recently used; and

retrieving an egress port identifier from an inline port mapping table using information from the selected entry.

9. The method of claim 8, wherein the inline port mapping table contains a plurality of associations between ingress and egress inline network ports, wherein one of the egress inline network ports is connected to a destination network of the egress packet.

10. A system comprising:

one or more inline tool devices configured to monitor and analyze a flow of network traffic;

a plurality of networks, two or more of the networks of the plurality of networks having an Layer 2 (L2) connection between the two or more networks of the plurality of networks, the L2 connection providing for communication between the two or more networks of the plurality of networks; and

an Advanced Inline Aggregation (AIA) device connected to each of the plurality of networks and connected to the one or more inline tool devices, the AIA device having stored therein a plurality of programming instructions, which when executed on the AIA device cause the AIA device to;

process an ingress packet received from an ingress inline network port of the AIA device connected to one of the plurality of networks to extract a source Media Access Control (MAC) address and a port identifier associated with the source MAC address;

look up the extracted source MAC address of the ingress packet in a MAC address table;

forward the ingress packet to the one or more inline tool devices;

process an egress packet received from the one or more inline tool devices to extract at least one of a source MAC address and the destination MAC address;

look up the extracted source MAC address of the egress packet in the MAC address table

detect whether there is an L2 connection based on finding the MAC source address in the MAC address table; and

transmit the egress packet to an egress inline network port connected to the one of the plurality of networks, the egress inline network port being selected based on whether the L2 connection was detected and at least one of the looked up source MAC address and the extracted destination MAC address of the egress packet.

11. The system of claim 10, wherein the MAC address table comprises a memory array storing table entries, the table entries each comprising a MAC address selected from at least one of a source MAC address and a destination MAC address and a port identifier that identifies an ingress inline network port or egress inline network port associated with the MAC address.

12. The system of claim 10, wherein looking up the extracted source MAC address of the ingress packet in a MAC address table further comprises determining whether the extracted source MAC address of the ingress packet is found in the MAC address table and creating a new entry in response to determining that the extracted source MAC address of the ingress packet is not found in the MAC address table, wherein the new entry comprises the extracted source MAC address of the ingress packet and the extracted port identifier associated with the extracted source MAC address.

13. The system of claim 12, wherein determining whether the extracted source MAC address of the ingress packet is found in the MAC address table further comprises determining whether the extracted port identifier associated with the extracted source MAC address of the ingress packet matches a port identifier associated with the MAC address found in the MAC address table and creating a new entry in response to determining that the extracted port identifier does not match the port identifier associated with the MAC address found in the MAC address table, wherein the new entry comprises the extracted source MAC address of the ingress packet and the extracted port identifier associated with the extracted source MAC address of the ingress packet.

14. The system of claim 10, wherein the programming instructions, which when executed on the AIA device further cause the AIA device to look up the extracted destination MAC address of the egress packet in the MAC address table.

15. The system of claim 14, wherein looking up the extracted source MAC address of the egress packet in the MAC address table further comprises:

determining whether a single entry matching the extracted source MAC address of the egress packet is found in the MAC address table; and

selecting the port identifier associated with the MAC address found in the MAC address table as the egress port for the egress packet, responsive to finding the single entry.

16. The system of claim 13, wherein looking up the extracted destination MAC address of the egress packet further comprises determining whether the extracted destination MAC address belongs to a multicast packet.

17. The system of claim 13, wherein looking up the extracted destination MAC address of the egress packet in the MAC address table further comprises:

determining whether a single entry or multiple entries matching the extracted destination MAC address of the egress packet is found in the MAC address table;

if so, selecting the single entry found or an entry of the multiple entries that was most recently used; and

retrieving an egress port identifier from an inline port mapping table using information from the selected entry.

18. The system of claim 17, wherein the inline port mapping table contains a plurality of associations between ingress and egress inline network ports, wherein one of the egress inline network ports is connected to a destination network of the egress packet, the destination network comprising the one of the plurality of networks.

19. The system of claim 10, wherein the AIA device comprises a Field Programmable Gate Array (FPGA).

20. The system of claim 11, wherein the table entries exceeding a predetermined age interval are aged out from the MAC address table.