Method of providing virtual router functionality through abstracted virtual identifiers

• US 7,817,633 B1
• Filed: 12/30/2005
• Issued: 10/19/2010
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Extreme Networks, Inc.
• Inventors: Gentry, Denton, Parker, David K.
• Primary Examiner(s): Patel, Jayanti K
• Assistant Examiner(s): Wyllie, Christopher T
• Application Number:
  US11/323,998
• Time in Patent Office: 1,754 Days
• Field of Search: 370/230, 370/352, 370/356, 370/379, 370/389, 370/392, 370/393, 370/401
• US Class Current: 370/392
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 12/4645 Details on frame tagging routing of packets H04L45/00; support for virtual LAN H04L49/354
• CPC Class Codes: H04L 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs
• CPC Class Codes: H04L 49/354 for supporting virtual local area networks [VLAN]

Abstract

A method of providing virtual router functionality to a packet responsive to one or more abstracted virtual packet identifiers is provided. The method occurs in a networking device having a router core. The one or more abstracted virtual identifiers are abstracted from one or more virtual identifiers derived from the packet, thus insulating the router core from changes in the one or more virtual identifiers. A packet is received having a VLAN field, and a key is formed from the VLAN field and at least one other packet field. The key is mapped into an abstracted virtual identifier using an indirection mapping process. One or more core virtual router functions are then performed responsive to the abstracted virtual identifier.

Claims

1. A method, performed in, by or for a networking device having a router core, of performing one or more core virtual router functions for a packet responsive to one or more abstracted virtual identifiers abstracted from one or more virtual identifiers derived from the packet, thus insulating the router core from changes in the one or more virtual identifiers, the method comprising the steps of:

receiving a packet having VLAN, VMAN, and ingress port fields;

forming a key from the VLAN, VMAN and ingress port fields;

masking the key with a key type determined responsive to the ingress port field;

mapping the masked key into an abstracted VLAN identifier (AVID) and abstracted virtual port identifier (AVPT) using a two-step indirection mapping process, comprising a first step and a second step,

wherein the first step comprises accessing a table having a plurality of entries, each having a content value and an index value, and locating an entry having a content value that matches the masked key, and the second step comprises mapping the index value of the matching entry into the AVID and AVPT by using the index value to identify an entry in an associated data store element containing or including the AVID and AVPT;

performing one or more core virtual router functions responsive to the AVID, the one or more core virtual router functions selected from the group consisting of;

qualifying OSI layer two MAC addresses;

limiting OSI layer two broadcasting or flooding domains;

performing OSI layer three indirection;

performing router MAC address detection; and

generating a CAM key in support of a packet processor operation; and

looking up a spanning tree state responsive to the AVPT.

2. A system, in or associated with a networking device, for determining, using a two-step indirection mapping process comprising a first step and a second step, an abstracted VLAN identifier (AVID) and an abstracted virtual port identifier (AVPT), for use in performing one or more core virtual router functions for a packet having a VLAN field, comprising:

first logic for forming a key from the VLAN field and at least one additional packet field;

first means for performing the first step of the two-step indirection mapping process by accessing a table having a plurality of entries, each having a content value and an index value, and locating an entry having a content value that matches the key; and

second means for performing the second step of the two-step indirection mapping process by mapping the index value of the matching entry into the AVID and the AVPT by using the index value to identify an entry in an associated data store element containing or including the AVID and AVPT; and

performing one or more core virtual router functions responsive to the AVID.

3. The system of claim 2 further comprising second logic for masking the key using a key type determined response to one or more packet fields.

4. A method in a router core of a networking device comprising:

receiving a packet having a VLAN field and at least one additional packet field;

forming a key from the VLAN field and the at least one additional packet field;

mapping the key into an abstracted VLAN identifier (AVID) and abstracted virtual port identifier (AVPT) using a two-step indirection mapping process having a first operation and a second operation;

wherein the first operation comprises accessing a table having a plurality of entries, each entry having a content value and an index value, and locating an entry having a content value that matches the key, and

wherein the second operation comprises mapping a corresponding index value of the located entry having the content value that matches the key into the AVID and AVPT by using the index value to identify an entry in an associated data store element containing or including the AVID and AVPT; and

performing one or more core virtual router functions responsive to the AVID.

5. The method of claim 4 wherein the one or more core virtual router functions comprises at least, determining a quality of service (QoS) for the packet responsive to the AVID.

6. The method of claim 4 the step of performing or more core virtual router functions responsive to the abstracted virtual identifier comprises performing one or more core virtual router functions, responsive to the AVID, selected from the group consisting of:

qualifying OSI layer two MAC addresses;

limiting OSI layer two broadcasting or flooding domains;

performing OSI layer three indirection;

performing router MAC address detection; and

generating a CAM key in support of a packet processor operation.

7. The method of claim 4 wherein the VLAN field is a super VLAN field having a 24-bit wide VLAN field.

8. The method of claim 4 wherein the key is a masked key.

9. The method of claim 8 wherein the key is masked using a key type determined responsive to the packet.

10. The method of claim 9 wherein the key is masked by wildcarding one or more fields of the key based upon the key type.

11. The method of claim 8 wherein the key is masked by wildcarding one or more fields, of entries of a ternary Context Addressable Memory (CAM), the one or more fields determined responsive to the packet.

12. The method of claim 4 wherein the table is stored on a, Context Addressable Memory (CAM), wherein the first operation of the two-step indirection mapping process comprises having the CAM search for and locate the entry whose content value matches the key, and wherein the second operation of the two-step indirection mapping process comprises using the index value of the matched entry to identify the entry in the associated data store element, which comprises an associated RAM, containing or including the AVID.

13. The method of claim 12 wherein the CAM is a binary CAM.

14. The method of claim 12 wherein the CAM is a ternary CAM, wherein each bit within a content value of the CAM comprises either a binary value of “

0”

or “

1,”

or a “

don'"'"'t care”

value.

15. The method of claim 4 wherein the table is stored in a RAM, wherein the first operation of the two-step indirection mapping process comprises applying a hash function to the key to determine a table index for a starting entry, and searching the table beginning with the starting entry to locate the entry whose content value matches the key, beginning with the starting entry, and wherein the second operation of the two-step indirection mapping process comprises using the index value of the matched entry to identify the entry in the associated data store element containing or including the AVID.

16. The method of claim 4 wherein the at least one additional packet field comprises a Virtual Metropolitan Network (VMAN) field.

17. The method of claim 4 wherein the at least one additional packet field comprises a Virtual Metropolitan Network (VMAN) field and an ingress port field.

18. The method of claim 4 wherein the at least one additional packet field comprises an ingress port field.

19. The method of claim 4 wherein the key is unmasked.

20. The method of claim 4 wherein the one or more core router functions comprise performing a spanning tree state lookup operation for an abstracted virtual port responsive to the AVPT.

21. The method of claim 4 wherein the packet is an ingress packet.

22. The method of claim 4 wherein the packet is an egress packet.

23. A networking device comprising:

a processor coupled with a router core of the networking device;

wherein the processor executes a set of instructions embedded on a memory causing the router core to perform a method comprising;

receiving a packet having a VLAN field and at least one additional packet field;

forming a key from the VLAN field and the at least one additional packet field;

mapping the key into an abstracted VLAN identifier (AVID) and abstracted virtual port identifier (AVPT) using a two-step indirection mapping process having a first operation and a second operation;

wherein the first operation comprises accessing a table having a plurality of entries, each entry having a content value and an index value, and

locating an entry having a content value that matches the key, and

wherein the second operation comprises mapping a corresponding index value of the located entry having the content value that matches the key into the AVID and AVPT by using the index value to identify an entry in an associated data store element containing or including the AVID and AVPT; and

performing one or more core virtual router functions responsive to the AVID.

24. The networking device of claim 23 wherein the at least one additional packet field comprises a Virtual Metropolitan Network (VMAN) field, and wherein the key is formed from the VLAN field, the VMAN field, and an ingress port number associated with the packet received.

25. The method of claim 23 wherein the one or more core virtual router functions performed responsive to the AVID are selected from the group consisting of:

qualifying OSI layer two MAC addresses;

limiting OSI layer two broadcasting or flooding domains;

performing OSI layer three indirection;

performing router MAC address detection; and

generating a CAM key in support of a packet processor operation.