System and method for providing a loop free topology in a network environment

• US 8,559,341 B2
• Filed: 11/08/2010
• Issued: 10/15/2013
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bulusu, Shekher
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): LEE, ANDREW CHUNG CHEUNG
• Application Number:
  US12/941,881
• Publication Number:
  US 20120113871A1
• Time in Patent Office: 1,072 Days
• Field of Search: 370/256, 370/352, 370/389, 370/390, 370/392, 370/395.31, 370/401
• US Class Current: 370/256
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/03 by updating link state protocols
• CPC Class Codes: H04L 45/18 Loop-free operations

Abstract

An example method is provided and includes executing an intermediate system to intermediate system (IS-IS) protocol for a first set of network links in a network. The method also includes executing a spanning tree protocol (STP) for a second set of network links, and generating a network topology that includes using a broadcast tree system identifier (ID) as a root bridge ID for the network. The method further includes communicating the root bridge ID to a neighboring network element. In more specific examples, an STP block is communicated to a redundant link, which connects a first switch and a second switch. The first and second switches can converge on the network topology using the broadcast tree system ID.

Claims

1. A method, comprising:

executing an intermediate system to intermediate system (IS-IS) protocol for a first set of network links in a hybrid network;

executing a spanning tree protocol (STP) for a second set of network links;

generating a network topology that includes using a broadcast tree system identifier (ID) as a root bridge ID for the hybrid network;

communicating the root bridge ID to a neighboring network element;

wherein the broadcast tree system ID is associated with the IS-IS protocol, and the root bridge ID is associated with the STP;

wherein a layer 2 gateway spanning tree protocol (“

L2G-STP”

) mechanism for implementing a segmented spanning tree and a layer 2 Gateway Interconnect Protocol (“

L2GIP”

) mechanism for building adjacencies between network elements are provided to prevent loops in the hybrid network; and

wherein the broadcast tree system ID is provided as the root bridge ID per virtual local area network (VLAN), and wherein the broadcast tree system ID is a Media Access Control address (MAC address).

2. The method of claim 1, wherein an STP block is communicated to a redundant link, which connects a first switch and a second switch, and wherein the first and second switches converge on the network topology using the broadcast tree system ID.

3. The method of claim 1, wherein the network includes a Data Center Ethernet (DCE) network and a Classical Ethernet (CE) network, which form a layer-2 (L2) broadcast domain.

4. The method of claim 1, wherein a selected gateway port is configured to receive a superior Bridge Protocol Data Unit (BPDU), and in response to the superior BPDU, the selected port is placed in a blocked state.

5. The method of claim 1, wherein an auto-detection mechanism is utilized to transition to an uplink port type in response to receiving a superior BPDU.

6. One or more non-transitory computer-readable storage media including code for execution that when executed by a processor is operable to perform operations comprising:

executing an intermediate system to intermediate system (IS-IS) protocol for a first set of network links in a hybrid network;

executing a spanning tree protocol (STP) for a second set of network links;

generating a network topology that includes using a broadcast tree system identifier (ID) as a root bridge ID for the hybrid network;

communicating the root bridge ID to a neighboring network element;

wherein the broadcast tree system ID is associated with the IS-IS protocol, and the root bridge ID is associated with the STP;

wherein a layer 2 gateway spanning tree protocol (“

L2G-STP”

) mechanism for implementing a segmented spanning tree and a layer 2 Gateway Interconnect Protocol (“

L2GIP”

) mechanism for building adjacencies between network elements are provided to prevent loops in the hybrid network; and

wherein the broadcast tree system ID is provided as the root bridge ID per virtual local area network (VLAN), and wherein the broadcast tree system ID is a Media Access Control address (MAC address).

7. The one or more non-transitory computer-readable storage media of claim 6, wherein an STP block is communicated to a redundant link, which connects a first switch and a second switch, and wherein the first and second switches converge on the network topology using the broadcast tree system ID.

8. The one or more non-transitory computer-readable storage media of claim 6, wherein the network includes a Data Center Ethernet (DCE) network and a Classical Ethernet (CE) network, which form a layer-2 (L2) broadcast domain.

9. The one or more non-transitory computer-readable storage media of claim 6, wherein a selected gateway port is configured to receive a superior Bridge Protocol Data Unit (BPDU), and in response to the superior BPDU, the selected port is placed in a blocked state.

10. The one or more non-transitory computer-readable storage media of claim 6, wherein an auto-detection mechanism is utilized to transition to an uplink port type in response to receiving a superior BPDU.

11. An apparatus, comprising:

a memory element configured to store electronic code,

a processor operable to execute instructions associated with the electronic code, and

a layer-2 (L2) gateway-spanning tree protocol (L2G-STP) module configured to interface with the processor and the memory element in order to cause the apparatus to;

execute an intermediate system to intermediate system (IS-IS) protocol for a first set of network links in a hybrid network;

execute a spanning tree protocol (STP) for a second set of network links;

generate a network topology that includes using a broadcast tree system identifier (ID) as a root bridge ID for the hybrid network;

communicate the root bridge ID to a neighboring network element;

wherein the broadcast tree system ID is associated with the IS-IS protocol, and the root bridge ID is associated with the STP;

wherein a layer 2 gateway spanning tree protocol (“

L2G-STP”

) mechanism for implementing a segmented spanning tree and a layer 2 Gateway Interconnect Protocol (“

L2GIP”

) mechanism for building adjacencies between network elements are provided to prevent loops in the hybrid network; and

wherein the broadcast tree system ID is provided as the root bridge ID per virtual local area network (VLAN), and wherein the broadcast tree system ID is a Media Access Control address (MAC address).

12. The apparatus of claim 11, wherein an STP block is communicated to a redundant link, which connects a first switch and a second switch, and wherein the first and second switches converge on the network topology using the broadcast tree system ID.

13. The apparatus of claim 11 wherein the network includes a Data Center Ethernet (DCE) network and a Classical Ethernet (CE) network, which form a layer-2 (L2) broadcast domain.

14. The apparatus of claim 11, wherein an auto-detection mechanism is utilized to transition to an uplink port type in response to receiving a superior BPDU.