Cisco Nexus 3000 series User manual

Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration
Guide, Release 6.x
First Published: 2013-04-29
Last Modified: 2018-02-15
Americas Headquarters
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
USA
http://www.cisco.com
Tel: [phone]
800 553-NETS (6387)
Fax: [phone]
Text Part Number: OL-29545-03

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.
The Cisco implementation of TCP header compression is an adaptation of a program developed by the University of California, Berkeley (UCB) as part of UCB's public domain version
of the UNIX operating system. All rights reserved. Copyright ©1981, Regents of the University of California.
NOTWITHSTANDING ANY OTHER WARRANTY HEREIN, ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED “AS IS" WITH ALL FAULTS.
CISCO AND THE ABOVE-NAMED SUPPLIERS DISCLAIM ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OR ARISING FROM A COURSE OF DEALING, USAGE, OR TRADE PRACTICE.
IN NO EVENT SHALL CISCO OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCIDENTAL DAMAGES, INCLUDING, WITHOUT
LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL, EVEN IF CISCO OR ITS SUPPLIERS
HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network
topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional
and coincidental.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: http://
www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership
relationship between Cisco and any other company. (1110R)
©2013-2018 Cisco Systems, Inc. All rights reserved.

CONTENTS
CHAPTER 1 New and Changed Information 1
New and Changed Information 1
CHAPTER 2 Overview 3
Layer 2 Ethernet Switching Overview 3
VLANs 3
Private VLANs 4
Spanning Tree 4
STP Overview 4
Rapid PVST+ 5
MST 5
STP Extensions 5
CHAPTER 3 Configuring VLANs 7
Information About VLANs 7
Understanding VLANs 7
VLAN Ranges 8
Creating, Deleting, and Modifying VLANs 9
About the VLAN Trunking Protocol 10
Guidelines and Limitations for VTP 10
Configuring a VLAN 11
Creating and Deleting a VLAN 11
Configuring a VLAN 12
Adding Ports to a VLAN 13
Triggering the VLAN Membership Consistency Checker 13
Configuring a VLAN as a Routed SVI 14
Configuring a VLAN as a Management SVI 15
Configuring VTP 15
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
OL-29545-03 iii

Verifying the VLAN Configuration 17
CHAPTER 4 Configuring Private VLANs 19
Information About Private VLANs 19
Primary and Secondary VLANs in Private VLANs 20
Private VLAN Ports 20
Primary, Isolated, and Community Private VLANs 21
Associating Primary and Secondary VLANs 22
Broadcast Traffic in Private VLANs 23
Private VLAN Port Isolation 23
Guidelines and Limitations for Private VLANs 23
Configuring a Private VLAN 24
Enabling Private VLANs 24
Configuring a VLAN as a Private VLAN 24
Associating Secondary VLANs with a Primary Private VLAN 25
Configuring an Interface as a Private VLAN Host Port 26
Configuring an Interface as a Private VLAN Promiscuous Port 27
Configuring a Layer 2 Interface as a Private VLAN Isolated Trunk Port 28
Configuring a Layer 2 Interface as a Private VLAN Promiscuous Trunk Port 33
Configuring VLAN Mapping for Selective Q-in-Q on a Private VLAN Secondary Trunk
Port 35
Verifying the Private VLAN Configuration 36
CHAPTER 5 Configuring Access and Trunk Interfaces 39
Information About Access and Trunk Interfaces 39
Understanding Access and Trunk Interfaces 39
Understanding IEEE 802.1Q Encapsulation 40
Understanding Access VLANs 41
Understanding the Native VLAN ID for Trunk Ports 42
Understanding Allowed VLANs 42
Understanding Native 802.1Q VLANs 42
Configuring Access and Trunk Interfaces 43
Configuring a LAN Interface as an Ethernet Access Port 43
Configuring Access Host Ports 44
Configuring Trunk Ports 44
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
iv OL-29545-03
Contents

Configuring the Native VLAN for 802.1Q Trunking Ports 45
Configuring the Allowed VLANs for Trunking Ports 45
Configuring Native 802.1Q VLANs 46
Verifying the Interface Configuration 47
CHAPTER 6 Configuring Switching Modes 49
Information About Switching Modes 49
Guidelines and Limitations for Switching Modes 50
Licensing Requirements for Switching Modes 51
Default Settings for Switching Modes 51
Configuring Switching Modes 51
Enabling Store-and-Forward Switching 51
Reenabling Cut-Through Switching 52
CHAPTER 7 Configuring Rapid PVST+ 53
Information About Rapid PVST+ 53
Understanding STP 53
STP Overview 53
Understanding How a Topology is Created 54
Understanding the Bridge ID 54
Bridge Priority Value 54
Extended System ID 55
STP MAC Address Allocation 55
Understanding BPDUs 56
Election of the Root Bridge 57
Creating the Spanning Tree Topology 57
Understanding Rapid PVST+ 58
Rapid PVST+ Overview 58
Rapid PVST+ BPDUs 59
Proposal and Agreement Handshake 60
Protocol Timers 61
Port Roles 61
Port States 62
Rapid PVST+ Port State Overview 62
Blocking State 63
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
OL-29545-03 v
Contents

Learning State 63
Forwarding State 63
Disabled State 64
Summary of Port States 64
Synchronization of Port Roles 64
Processing Superior BPDU Information 65
Processing Inferior BPDU Information 66
Spanning-Tree Dispute Mechanism 66
Port Cost 66
Port Priority 67
Rapid PVST+ and IEEE 802.1Q Trunks 67
Rapid PVST+ Interoperation with Legacy 802.1D STP 67
Rapid PVST+ Interoperation with 802.1s MST 68
Configuring Rapid PVST+ 68
Enabling Rapid PVST+ 68
Enabling Rapid PVST+ per VLAN 69
Configuring the Root Bridge ID 70
Configuring a Secondary Root Bridge 71
Configuring the Rapid PVST+ Port Priority 72
Configuring the Rapid PVST+ Path-Cost Method and Port Cost 73
Configuring the Rapid PVST+ Bridge Priority of a VLAN 73
Configuring the Rapid PVST+ Hello Time for a VLAN 74
Configuring the Rapid PVST+ Forward Delay Time for a VLAN 75
Configuring the Rapid PVST+ Maximum Age Time for a VLAN 75
Specifying the Link Type 75
Restarting the Protocol 76
Verifying the Rapid PVST+ Configuration 76
Triggering the VLAN STP State Consistency Checker 77
CHAPTER 8 Configuring Multiple Spanning Tree 79
Information About MST 79
MST Overview 79
MST Regions 80
MST BPDUs 80
MST Configuration Information 81
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
vi OL-29545-03
Contents

IST, CIST, and CST 81
IST, CIST, and CST Overview 81
Spanning Tree Operation Within an MST Region 82
Spanning Tree Operations Between MST Regions 82
MST Terminology 83
Hop Count 84
Boundary Ports 84
Spanning-Tree Dispute Mechanism 85
Port Cost and Port Priority 86
Interoperability with IEEE 802.1D 86
Interoperability with Rapid PVST+: Understanding PVST Simulation 87
Configuring MST 87
MST Configuration Guidelines 87
Enabling MST 87
Entering MST Configuration Mode 88
Specifying the MST Name 89
Specifying the MST Configuration Revision Number 90
Specifying the Configuration on an MST Region 90
Mapping and Unmapping VLANs to MST Instances 92
Mapping Secondary VLANs to Same MSTI as Primary VLANs for Private VLANs 92
Configuring the Root Bridge 93
Configuring a Secondary Root Bridge 94
Configuring the Port Priority 95
Configuring the Port Cost 96
Configuring the Switch Priority 96
Configuring the Hello Time 97
Configuring the Forwarding-Delay Time 98
Configuring the Maximum-Aging Time 98
Configuring the Maximum-Hop Count 99
Configuring PVST Simulation Globally 99
Configuring PVST Simulation Per Port 100
Specifying the Link Type 101
Restarting the Protocol 101
Verifying the MST Configuration 102
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
OL-29545-03 vii
Contents

CHAPTER 9 Configuring STP Extensions 103
Information About STP Extensions 103
Overview 103
Understanding STP Port Types 103
Spanning Tree Edge Ports 104
Spanning Tree Network Ports 104
Spanning Tree Normal Ports 104
Understanding Bridge Assurance 104
Understanding BPDU Guard 105
Understanding BPDU Filtering 105
Understanding Loop Guard 106
Understanding Root Guard 107
Configuring STP Extensions 107
STP Extensions Configuration Guidelines 107
Configuring Spanning Tree Port Types Globally 108
Configuring Spanning Tree Edge Ports on Specified Interfaces 109
Configuring Spanning Tree Network Ports on Specified Interfaces 110
Enabling BPDU Guard Globally 111
Enabling BPDU Guard on Specified Interfaces 111
Enabling BPDU Filtering Globally 112
Enabling BPDU Filtering on Specified Interfaces 113
Enabling Loop Guard Globally 114
Enabling Loop Guard or Root Guard on Specified Interfaces 115
Verifying the STP Extension Configuration 116
Troubleshooting Loop Detection Error Message 116
Generating Syslog Error Messages 117
CHAPTER 10 Configuring LLDP 119
Information About Global LLDP Commands 119
Configuring LLDP 120
Information About LLDP Management TLV IP Addresses 121
Configuring LLDP Management TLV IP Addresses on an Interface 123
Configuring Interface LLDP 124
MIBs for LLDP 125
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
viii OL-29545-03
Contents

CHAPTER 11 Configuring MAC Address Tables 127
Information About MAC Addresses 127
Guidelines for Configuring the MAC Address Tables 128
MAC Address Movement 128
Configuring MAC Addresses 128
Configuring Static MAC Addresses 128
Configuring the Aging Time for the MAC Table 129
Configuring MAC Move Loop Detection 130
Disabling MAC Address Learning on Layer 2 Interfaces 130
Clearing Dynamic Addresses from the MAC Table 131
Verifying the MAC Address Configuration 131
Triggering the Layer 2 Consistency Checker 132
CHAPTER 12 Configuring IGMP Snooping 135
Information About IGMP Snooping 135
IGMPv1 and IGMPv2 136
IGMPv3 137
IGMP Snooping Querier 137
IGMP Forwarding 137
Configuring IGMP Snooping Parameters 138
Verifying the IGMP Snooping Configuration 140
CHAPTER 13 Configuring Traffic Storm Control 143
Information About Traffic Storm Control 143
Guidelines and Limitations for Traffic Storm Control 145
Default Settings for Traffic Storm Control 146
Configuring Traffic Storm Control 146
Verifying the Traffic Storm Control Configuration 147
Traffic Storm Control Example Configuration 148
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
OL-29545-03 ix
Contents

Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 6.x
xOL-29545-03
Contents