Layer 2 (Link Aggregation) Configuration Guide, Cisco IOS XE Release 3E (Cisco WLC 5700 Series) First Published: June 16, 2014 Last Modified: 0, Americas Headquarters Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 USA http://www.cisco.com Tel: 408 526-4000 800 553-NETS (6387) Fax: 408 527-0883 Text Part Number: OL-32322-01 THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS, INFORMATION, AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS. THE SOFTWARE LICENSE AND LIMITED WARRANTY FOR THE ACCOMPANYING PRODUCT ARE SET FORTH IN THE INFORMATION PACKET THAT SHIPPED WITH THE PRODUCT AND ARE INCORPORATED HEREIN BY THIS REFERENCE. IF YOU ARE UNABLE TO LOCATE THE SOFTWARE LICENSE OR LIMITED WARRANTY, CONTACT YOUR CISCO REPRESENTATIVE FOR A COPY. 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CONTENTS Preface Preface vii Obtaining Documentation and Submitting a Service Request vii Document Conventions vii Related Documentation ix CHAPTER 1 Using the Command-Line Interface 1 Information About Using the Command-Line Interface 1 Command Modes 1 Using the Help System 3 Understanding Abbreviated Commands 5 No and Default Forms of Commands 5 CLI Error Messages 5 Configuration Logging 6 How to Use the CLI to Configure Features 6 Configuring the Command History 6 Changing the Command History Buffer Size 6 Recalling Commands 7 Disabling the Command History Feature 7 Enabling and Disabling Editing Features 8 Editing Commands Through Keystrokes 8 Editing Command Lines That Wrap 10 Searching and Filtering Output of show and more Commands 11 Accessing the CLI Through a Console Connection or Through Telnet 11 CHAPTER 2 Configuring EtherChannels and Link-State Tracking 13 Finding Feature Information 13 Restrictions for EtherChannels 13 Layer 2 (Link Aggregation) Configuration Guide, Cisco IOS XE Release 3E (Cisco WLC 5700 Series) OL-32322-01 iii Contents Information About EtherChannels 14 EtherChannel Overview 14 EtherChannel Modes 15 EtherChannel on Controllers 15 EtherChannel Link Failover 16 Channel Groups and Port-Channel Interfaces 16 Port Aggregation Protocol 18 PAgP Modes 18 Silent Mode 19 PAgP Learn Method and Priority 19 PAgP Interaction with Other Features 20 Link Aggregation Control Protocol 21 LACP Modes 21 LACP and Link Redundancy 22 LACP Interaction with Other Features 22 EtherChannel On Mode 22 Load-Balancing and Forwarding Methods 23 MAC Address Forwarding 23 IP Address Forwarding 24 Load-Balancing Advantages 24 EtherChannel and Controller Stacks 25 Controller Stack and PAgP 26 Controller Stacks and LACP 26 Default EtherChannel Configuration 26 EtherChannel Configuration Guidelines 27 Layer 2 EtherChannel Configuration Guidelines 29 Layer 3 EtherChannel Configuration Guidelines 30 How to Configure EtherChannels 30 Configuring Layer 2 EtherChannels (CLI) 30 Configuring Layer 3 EtherChannels (CLI) 32 Configuring EtherChannel Load-Balancing (CLI) 34 Configuring EtherChannel Extended Load-Balancing (CLI) 36 Configuring the PAgP Learn Method and Priority (CLI) 37 Configuring LACP Hot-Standby Ports 38 Configuring the LACP Max Bundle Feature (CLI) 39 Layer 2 (Link Aggregation) Configuration Guide, Cisco IOS XE Release 3E (Cisco WLC 5700 Series) iv OL-32322-01 Contents Configuring the Port Channel Min-Links Feature (CLI) 40 Configuring the LACP System Priority (CLI) 41 Configuring the LACP Port Priority (CLI) 42 Monitoring EtherChannel, PAgP, and LACP Status 44 Configuration Examples for Configuring EtherChannels 45 Configuring Layer 2 EtherChannels: Examples 45 Configuring Layer 3 EtherChannels: Examples 45 Configuring LACP Hot-Standby Ports: Example 46 Additional References for EtherChannels 46 Feature Information for EtherChannels 48 CHAPTER 3 Configuring Flex Links and the MAC Address-Table Move Update Feature 49 Finding Feature Information 49 Restrictions for Configuring Flex Links and MAC Address-Table Move Update 49 Information About Flex Links and MAC Address-Table Move Update 50 Flex Links 50 Flex Links Configuration 51 VLAN Flex Links Load Balancing and Support 51 Multicast Fast Convergence with Flex Links Failover 52 Learning the Other Flex Links Port as the mrouter Port 52 Generating IGMP Reports 52 Leaking IGMP Reports 53 MAC Address-Table Move Update 53 Flex Links VLAN Load Balancing Configuration Guidelines 55 MAC Address-Table Move Update Configuration Guidelines 55 Default Flex Links and MAC Address-Table Move Update Configuration 55 How to Configure Flex Links and the MAC Address-Table Move Update Feature 56 Configuring Flex Links (CLI) 56 Configuring a Preemption Scheme for a Pair of Flex Links (CLI) 57 Configuring VLAN Load Balancing on Flex Links (CLI) 59 Configuring MAC Address-Table Move Update (CLI) 60 Configuring a Controller to Obtain and Process MAC Address-Table Move Update Messages (CLI) 61 Monitoring Flex Links, Multicast Fast Convergence, and MAC Address-Table Move Update 62 Configuration Examples for Flex Links 63 Layer 2 (Link Aggregation) Configuration Guide, Cisco IOS XE Release 3E (Cisco WLC 5700 Series) OL-32322-01 v Contents Configuring Flex Links: Examples 63 Configuring VLAN Load Balancing on Flex Links: Examples 64 Configuring the MAC Address-Table Move Update: Examples 65 Configuring Multicast Fast Convergence with Flex Links Failover: Examples 66 Additional References for Flex Links and MAC Address-Table Move Update 68 Feature Information for Flex Links and MAC Address-Table Move Update 69 CHAPTER 4 Configuring UniDirectional Link Detection 71 Finding Feature Information 71 Restrictions for Configuring UDLD 71 Information About UDLD 72 Modes of Operation 72 Normal Mode 72 Aggressive Mode 72 Methods to Detect Unidirectional Links 73 Neighbor Database Maintenance 73 Event-Driven Detection and Echoing 73 UDLD Reset Options 74 Default UDLD Configuration 74 How to Configure UDLD 75 Enabling UDLD Globally (CLI) 75 Enabling UDLD on an Interface (CLI) 76 Monitoring and Maintaining UDLD 77 Additional References for UDLD 78 Feature Information for UDLD 79 Layer 2 (Link Aggregation) Configuration Guide, Cisco IOS XE Release 3E (Cisco WLC 5700 Series) vi OL-32322-01 Preface • Obtaining Documentation and Submitting a Service Request, page vii • Document Conventions, page vii • Related Documentation, page ix Obtaining Documentation and Submitting a Service Request For information on obtaining documentation, submitting a service request, and gathering additional information, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at: http://www.cisco.com/c/en/us/td/docs/general/whatsnew/whatsnew.html Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed and set content to be delivered directly to your desktop using a reader 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The RSS feeds are a free service and Cisco currently supports RSS version 2.0. Document Conventions This document uses the following conventions: Convention Description ^ or Ctrl Both the ^ symbol and Ctrl represent the Control (Ctrl) key on a keyboard. For example, the key combination ^D or Ctrl-D means that you hold down the Control key while you press the D key. (Keys are indicated in capital letters but are not case sensitive.) bold font Commands and keywords and user-entered text appear in bold font. Italic font Document titles, new or emphasized terms, and arguments for which you supply values are in italic font. Courier font Terminal sessions and information the system displays appear in courier font. Layer 2 (Link Aggregation) Configuration