Flexible inline arrangements for guiding traffic through network tools

1. A method for configuring a guiding arrangement to be implemented by a packet broker, the method comprising:

receiving the guiding arrangement, the guiding arrangement indicative to the packet broker of how to guide data packets through a specific sequence of inline inspection devices that are coupled to the packet broker;

identifying egress ports through which the packet broker forwards data packets to the inline inspection devices;

for each egress port,

implementing an egress translation scheme that causes an internal identifier appended to each data packet by the packet broker to be translated to an external identifier before transmission to a corresponding inline inspection device; and

identifying ingress ports through which the packet broker receives data packets from the inline inspection devices;

for each ingress port,

implementing an ingress translation scheme that causes the external identifier appended to each data packet by the packet broker to be translated to another internal identifier.

2. The method of claim 1 , wherein each internal identifier assigned to a data packet upon receipt by the packet broker is unique across all traffic flows received by the packet broker and all inline inspection devices coupled directly to the packet broker.

3. The method of claim 1 , wherein the inline inspection devices include intrusion detection systems, intrusion prevention systems, or both.

4. The method of claim 1 , further comprising:

programming a content-addressable memory (CAM) with packet-matching criteria;

applying the packet-matching criteria to incoming data packets; and

adding, based on a result of said applying, a metadata field to each incoming data packet that specifies the internal identifier.

5. The method of claim 4 , wherein the packet-matching criteria include at least one of: an ingress port identifier, a source node identifier, a destination node identifier, a unique packet identifier, a packet length, a transmission protocol, a priority level identifier, a payload data characteristic, an application port setting, or a flow map.

6. The method of claim 4 , further comprising:

translating, based on the ingress translation scheme, the metadata field of a particular data packet to a unique value each time the particular data packet is received from an inline inspection device.

7. The method of claim 1 , wherein the specific sequence of inline inspection devices includes a subset of all inline inspection devices coupled to the packet broker.

8. The method of claim 1 , wherein the internal identifier and the external identifier are Virtual Local Area Network (VLAN) identifiers.

9. The method of claim 1 , further comprising:

creating a trunk that includes multiple egress ports corresponding to multiple inline inspection devices,

wherein creation of the trunk causes a particular data packet having an internal identifier associated with one of the multiple egress ports to be broadcast to all of the multiple egress ports.

10. A method for guiding traffic flows through sequences of inline network tools, the method comprising:

receiving a data packet at a network ingress port of a packet broker connected to a network;

applying packet-matching criteria to determine an internal identifier for the data packet that corresponds to a predetermined sequence of inline network tools through which the data packet is to be guided;

adding a metadata field to the data packet that specifies the internal identifier;

guiding the data packet through a first inline network tool by

forwarding, based on the internal identifier, the data packet to a tool egress port of the packet broker, the tool egress port being coupled to the first inline network tool;

translating the internal identifier to an external identifier;

transmitting the data packet to the first inline network tool; and

translating the external identifier to another internal identifier upon receiving the data packet at a tool ingress port of the packet broker, the tool ingress port being connected to the first inline network tool; and

forwarding, based on the other internal identifier, the data packet to an egress port of the packet broker, the egress port being connected to another inline network tool included in the predetermined sequence or the network.

11. The method of claim 10 , wherein each internal identifier is a unique Virtual Local Area Network (VLAN) identifier that is used to guide the data packet to a next hop in the predetermined sequence of inline network tools.

12. The method of claim 10 , wherein each internal identifier is unique across all traffic flows received by the packet broker and all inline network tools coupled to the packet broker.

13. The method of claim 10 , wherein said guiding is performed by a programmable switching fabric in the packet broker.

14. The method of claim 10 , wherein the packet-matching criteria reside within a content-addressable memory (CAM) of the packet broker and are automatically applied by a programmable switching fabric upon receiving the data packet at the network ingress port.

15. The method of claim 10 , further comprising:

monitoring a status of each inline network tool included in the predetermined sequence;

determining that a particular inline network tool is not functioning properly; and

automatically modifying the predetermined sequence to bypass the particular inline network tool.

16. The method of claim 15 , wherein said automatically modifying the predetermined sequence comprises:

modifying an ingress translation scheme implemented by the packet broker so that the external identifier of the data packet is translated to a new internal identifier rather than an existing internal identifier associated with the particular inline network tool.

17. The method of claim 10 , further comprising:

stripping the metadata field from the data packet; and

forwarding the data packet onto the network for delivery to a destination node communicatively coupled to a network egress port.

18. A method comprising:

receiving a data packet at a network ingress port of a network appliance connected to a network;

applying packet-matching criteria, by the network appliance, to determine a predetermined sequence of inline network tools through which the data packet is to be guided; and

guiding the data packet through the predetermined sequence of inline network tools, by the network appliance, by

translating an internal identifier added to the data packet to an external identifier before transmission to each of the inline network tools, and

translating the external identifier to a different internal identifier each time the data packet is received at a tool ingress port coupled to one of the inline network tools.

19. The method of claim 18 , wherein each internal identifier is a Virtual Local Area Network (VLAN) identifier that is used to guide the data packet to a next hop in the predetermined sequence of inline network tools.

20. The method of claim 18 , further comprising:

appending a metadata field to the data packet that includes a value corresponding to the internal identifier or the external identifier assigned to the data packet by the network appliance.

21. The method of claim 18 , wherein the inline network tool is shared across multiple traffic flows.

22. The method of claim 21 , wherein the external identifier is unique across the multiple traffic flows, and wherein the external identifier enables the network appliance to distinguish the data packet from other data packets corresponding to other traffic flows guided through the inline network tool.