H3C S12500X-AF Series User manual
H3C S12500X-AF Switch Series
Layer 2—LAN Switching Configuration Guide
New H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: Release 2609 and later
Document version: 6W102-20181204
Copyright © 2016-2019, New H3C Technologies Co., Ltd. and its licensors
All rights reserved
No part of this manual may be reproduced or transmitted in any form or by any means without prior written
consent of New H3C Technologies Co., Ltd.
Trademarks
Except for the trademarks of New H3C Technologies Co., Ltd., any trademarks that may be mentioned in this
document are the property of their respective owners.
Notice
The information in this document is subject to change without notice. All contents in this document, including
statements, information, and recommendations, are believed to be accurate, but they are presented without
warranty of any kind, express or implied. H3C shall not be liable for technical or editorial errors or omissions
contained herein.
Preface
This configuration guide describes the Layer 2—LAN switching fundamentals and configuration
procedures. It covers the following features and tasks:
•Flow control and load sharing.
•User isolation in the same VLAN and VLAN configuration.
•Layer 2 loop elimination.
This preface includes the following topics about the documentation:
•Audience.
•Conventions.
•Documentation feedback.
Audience
This documentation is intended for:
•Network planners.
•Field technical support and servicing engineers.
•Network administrators working with the S12500X-AF switch series.
Conventions
The following information describes the conventions used in the documentation.
Command conventions
Convention Description
Boldface Bold text represents commands and keywords that you enter literally as shown.
Italic Italic text represents arguments that you replace with actual values.
[ ] Square brackets enclose syntax choices (keywords or arguments) that are optional.
{ x | y | ... }
Braces enclose a set of required syntax choices separated by vertical bars, from which
you select one.
[ x | y | ... ]
Square brackets enclose a set of optional syntax choices separated by vertical bars,
from which you select one or none.
{ x | y | ... } *
Asterisk marked braces enclose a set of required syntax choices separated by vertical
bars, from which you select at least one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by vertical
bars, from which you select one choice, multiple choices, or none.
&<1-n> The argument or keyword and argument combination before the ampersand (&) sign
can be entered 1 to n times.
# A line that starts with a pound (#) sign is comments.
GUI conventions
Convention Description
Boldface Window names, button names, field names, and menu items are in Boldface. For
Convention Description
example, the New Use
r
window appears; click O
K
.
> Multi-level menus are separated by angle brackets. For example, File > Create >
Folder.
Symbols
Convention Description
WARNING! An alert that calls attention to important information that if not understood or followed
can result in personal injury.
CAUTION: An alert that calls attention to important information that if not understood or followed
can result in data loss, data corruption, or damage to hardware or software.
IMPORTANT: An alert that calls attention to essential information.
NOTE: An alert that contains additional or supplementary information.
TIP: An alert that provides helpful information.
Network topology icons
Convention Description
Represents a generic network device, such as a router, switch, or firewall.
Represents a routing-capable device, such as a router or Layer 3 switch.
Represents a generic switch, such as a Layer 2 or Layer 3 switch, or a router that
supports Layer 2 forwarding and other Layer 2 features.
Represents an access controller, a unified wired-WLAN module, or the access
controller engine on a unified wired-WLAN switch.
Represents an access point.
Wireless terminator unit.
Wireless terminator.
Represents a mesh access point.
Represents omnidirectional signals.
Represents directional signals.
Represents a security product, such as a firewall, UTM, multiservice security
gateway, or load balancing device.
Represents a security card, such as a firewall, load balancing, NetStream, SSL VPN,
IPS, or ACG card.
T
T
T
T
Examples provided in this document
Examples in this document might use devices that differ from your device in hardware model,
configuration, or software version. It is normal that the port numbers, sample output, screenshots,
and other information in the examples differ from what you have on your device.
Documentation feedback
You can e-mail your comments about product documentation to info@h3c.com.
We appreciate your comments.
i
Contents
Configuring Ethernet interfaces ···························································1
Ethernet interface naming conventions ···························································································1
Configuring a management Ethernet interface··················································································1
Configuring common Ethernet interface settings ···············································································1
Splitting a 40-GE interface and combining 10-GE breakout interfaces·············································2
Configuring basic settings of an Ethernet interface or subinterface·················································3
Configuring the link mode of an Ethernet interface······································································4
Configuring jumbo frame support ····························································································4
Configuring physical state change suppression on an Ethernet interface ·········································5
Configuring dampening on an Ethernet interface ········································································6
Enabling loopback testing on an Ethernet interface·····································································7
Configuring generic flow control on an Ethernet interface ·····························································8
Configuring PFC on an Ethernet interface·················································································9
Setting the statistics polling interval ······················································································· 10
Configuring storm suppression ····························································································· 10
Configuring a Layer 2 Ethernet interface ······················································································· 11
Configuring storm control on an Ethernet interface ··································································· 11
Forcibly bringing up a fiber port ···························································································· 12
Configuring a Layer 3 Ethernet interface or subinterface··································································· 14
Setting the MTU for an Ethernet interface or subinterface ·························································· 14
Displaying and maintaining an Ethernet interface or subinterface ······················································· 14
Configuring loopback, null, and inloopback interfaces ···························· 16
Configuring a loopback interface ································································································· 16
Configuring a null interface········································································································· 16
Configuring an inloopback interface ····························································································· 17
Displaying and maintaining loopback, null, and inloopback interfaces·················································· 17
Bulk configuring interfaces ······························································· 18
Configuration restrictions and guidelines ······················································································· 18
Configuration procedure ············································································································ 18
Displaying and maintaining bulk interface configuration···································································· 19
Configuring the MAC address table···················································· 20
Overview································································································································ 20
How a MAC address entry is created····················································································· 20
Types of MAC address entries ····························································································· 20
MAC address table configuration task list ······················································································ 21
Configuring MAC address entries ································································································ 22
Configuration guidelines ····································································································· 22
Adding or modifying a static or dynamic MAC address entry globally ············································ 22
Adding or modifying a static or dynamic MAC address entry on an interface ·································· 22
Adding or modifying a blackhole MAC address entry································································· 23
Adding or modifying a multiport unicast MAC address entry························································ 23
Disabling MAC address learning ································································································· 24
Disabling global MAC address learning ·················································································· 24
Disabling MAC address learning on interfaces ········································································· 25
Setting the aging timer for dynamic MAC address entries ································································· 25
Enabling MAC address synchronization ························································································ 26
Configuring MAC address move notifications and suppression ·························································· 27
Enabling ARP fast update for MAC address moves ········································································· 28
Enabling MAC address learning at ingress ···················································································· 29
Configuring the base MAC address······························································································ 29
Enabling SNMP notifications for the MAC address table··································································· 30
Displaying and maintaining the MAC address table ········································································· 30
MAC address table configuration example····················································································· 31
Network requirements ········································································································ 31
ii
Configuration procedure ····································································································· 31
Verifying the configuration ··································································································· 31
Configuring MAC Information···························································· 33
Enabling MAC Information ········································································································· 33
Configuring the MAC Information mode ························································································ 33
Setting the MAC change notification interval ·················································································· 34
Setting the MAC Information queue length ···················································································· 34
MAC Information configuration example························································································ 34
Network requirements ········································································································ 34
Configuration restrictions and guidelines ················································································ 34
Configuration procedure ····································································································· 35
Configuring Ethernet link aggregation ················································· 37
Basic concepts ························································································································ 37
Aggregation group, member port, and aggregate interface ························································· 37
Aggregation states of member ports in an aggregation group······················································ 37
Operational key················································································································· 38
Configuration types············································································································ 38
Link aggregation modes······································································································ 39
Aggregating links in static mode ·································································································· 39
Choosing a reference port ··································································································· 39
Setting the aggregation state of each member port ··································································· 39
Aggregating links in dynamic mode······························································································ 40
LACP······························································································································ 41
How dynamic link aggregation works ····················································································· 42
Edge aggregate interface··········································································································· 44
Load sharing modes for link aggregation groups············································································· 44
Ethernet link aggregation configuration task list ·············································································· 44
Configuring an aggregation group································································································ 45
Configuration restrictions and guidelines ················································································ 45
Configuring a Layer 2 aggregation group ················································································ 45
Configuring a Layer 3 aggregation group ················································································ 46
Configuring an aggregate interface ······························································································ 48
Configuring the description of an aggregate interface ································································ 48
Setting the MAC address for an aggregate interface ································································· 48
Specifying ignored VLANs for a Layer 2 aggregate interface······················································· 49
Setting the MTU for a Layer 3 aggregate interface···································································· 49
Setting the minimum and maximum numbers of Selected ports for an aggregation group ················· 50
Setting the expected bandwidth for an aggregate interface························································· 51
Configuring an edge aggregate interface ················································································ 51
Enabling BFD for an aggregation group·················································································· 52
Shutting down an aggregate interface ···················································································· 53
Restoring the default settings for an aggregate interface···························································· 53
Configuring load sharing for link aggregation groups ······································································· 54
Setting load sharing modes for link aggregation groups ····························································· 54
Enabling local-first load sharing for link aggregation·································································· 55
Configuring link aggregation load sharing algorithm settings ······················································· 55
Enabling link-aggregation traffic redirection ··················································································· 56
Configuration restrictions and guidelines ················································································ 56
Configuration procedure ····································································································· 57
Configuring the link aggregation capability for the device ·································································· 57
Displaying and maintaining Ethernet link aggregation ······································································ 58
Ethernet link aggregation configuration examples ··········································································· 58
Layer 2 static aggregation configuration example ····································································· 58
Layer 2 dynamic aggregation configuration example ································································· 60
Layer 2 aggregation load sharing configuration example···························································· 62
Layer 2 edge aggregate interface configuration example ··························································· 64
Layer 3 static aggregation configuration example ····································································· 66
Layer 3 dynamic aggregation configuration example ································································· 67
Layer 3 aggregation load sharing configuration example···························································· 68
Layer 3 edge aggregate interface configuration example ··························································· 70
iii
Configuring port isolation ································································· 72
Assigning a port to an isolation group ··························································································· 72
Displaying and maintaining port isolation······················································································· 72
Port isolation configuration example····························································································· 73
Network requirements ········································································································ 73
Configuration procedure ····································································································· 73
Verifying the configuration ··································································································· 73
Configuring spanning tree protocols ··················································· 75
STP ······································································································································ 75
STP protocol frames ·········································································································· 75
Basic concepts in STP········································································································ 77
Calculation process of the STP algorithm ··············································································· 78
RSTP ···································································································································· 84
RSTP protocol frames ········································································································ 84
Basic concepts in RSTP ····································································································· 84
How RSTP works ·············································································································· 85
RSTP BPDU processing ····································································································· 85
PVST ···································································································································· 86
PVST protocol frames ········································································································ 86
Basic concepts in PVST······································································································ 87
How PVST works ·············································································································· 87
MSTP···································································································································· 87
MSTP features·················································································································· 87
MSTP protocol frames········································································································ 87
MSTP basic concepts········································································································· 89
How MSTP works·············································································································· 92
MSTP implementation on devices ························································································· 93
Rapid transition mechanism································································································· 93
Protocols and standards ············································································································ 95
Spanning tree configuration task lists ··························································································· 96
STP configuration task list ··································································································· 96
RSTP configuration task list································································································· 97
PVST configuration task list ································································································· 97
MSTP configuration task list ································································································ 98
Setting the spanning tree mode··································································································· 99
Configuring an MST region ········································································································ 99
Configuring the root bridge or a secondary root bridge ··································································· 100
Configuring the device as the root bridge of a specific spanning tree ·········································· 101
Configuring the device as a secondary root bridge of a specific spanning tree ······························ 101
Configuring the device priority··································································································· 101
Configuring the maximum hops of an MST region ········································································· 102
Configuring the network diameter of a switched network································································· 102
Setting spanning tree timers ····································································································· 103
Configuration restrictions and guidelines ·············································································· 103
Configuration procedure ··································································································· 103
Setting the timeout factor ········································································································· 104
Configuring the BPDU transmission rate ····················································································· 104
Configuring edge ports ············································································································ 105
Configuration restrictions and guidelines ·············································································· 105
Configuration procedure ··································································································· 105
Configuring path costs of ports·································································································· 105
Specifying a standard for the device to use when it calculates the default path cost ······················· 106
Configuring path costs of ports ··························································································· 108
Configuration example······································································································ 108
Configuring the port priority ······································································································ 109
Configuring the port link type ···································································································· 109
Configuration restrictions and guidelines ·············································································· 109
Configuration procedure ··································································································· 110
Configuring the mode a port uses to recognize and send MSTP frames············································· 110
Enabling outputting port state transition information······································································· 111
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Enabling the spanning tree feature ···························································································· 111
Enabling the spanning tree feature in STP/RSTP/MSTP mode·················································· 111
Enabling the spanning tree feature in PVST mode·································································· 111
Performing mCheck················································································································ 112
Configuration restrictions and guidelines ·············································································· 112
Performing mCheck globally ······························································································ 112
Performing mCheck in interface view ··················································································· 112
Disabling inconsistent PVID protection ······················································································· 113
Configuring Digest Snooping ···································································································· 113
Configuration restrictions and guidelines ·············································································· 114
Configuration procedure ··································································································· 114
Digest Snooping configuration example ··············································································· 114
Configuring No Agreement Check ····························································································· 115
Configuration prerequisites································································································ 116
Configuration procedure ··································································································· 117
No Agreement Check configuration example ········································································· 117
Configuring TC Snooping········································································································· 117
Configuration restrictions and guidelines ·············································································· 118
Configuration procedure ··································································································· 118
Configuring protection features ································································································· 118
Configuring BPDU guard··································································································· 119
Enabling root guard ········································································································· 120
Enabling loop guard ········································································································· 120
Configuring port role restriction··························································································· 121
Configuring TC-BPDU transmission restriction······································································· 121
Enabling TC-BPDU guard ································································································· 122
Enabling BPDU drop ········································································································ 122
Enabling PVST BPDU guard······························································································ 123
Enabling the device to log events of detecting or receiving TC BPDUs ·············································· 123
Enabling SNMP notifications for new-root election and topology change events ·································· 123
Displaying and maintaining the spanning tree ·············································································· 124
Spanning tree configuration example ························································································· 125
MSTP configuration example ····························································································· 125
PVST configuration example······························································································ 128
Configuring loop detection······························································ 132
Overview······························································································································ 132
Loop detection mechanism································································································ 132
Loop detection interval ····································································································· 133
Loop protection actions····································································································· 133
Port status auto recovery ·································································································· 133
Loop detection configuration task list·························································································· 134
Enabling loop detection ··········································································································· 134
Enabling loop detection globally ························································································· 134
Enabling loop detection on a port························································································ 134
Setting the loop protection action······························································································· 135
Setting the global loop protection action ··············································································· 135
Setting the loop protection action on a Layer 2 Ethernet interface ·············································· 135
Setting the loop protection action on a Layer 2 aggregate interface ············································ 135
Setting the loop detection interval ······························································································ 135
Displaying and maintaining loop detection ··················································································· 136
Loop detection configuration example ························································································ 136
Network requirements ······································································································ 136
Configuration procedure ··································································································· 136
Verifying the configuration ································································································· 137
Configuring VLANs ······································································· 139
Overview······························································································································ 139
VLAN frame encapsulation ································································································ 139
Protocols and standards ··································································································· 140
Configuring basic VLAN settings ······························································································· 140
Configuring VLAN interfaces ···································································································· 141
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Configuring port-based VLANs·································································································· 142
Introduction ···················································································································· 142
Assigning an access port to a VLAN···················································································· 143
Assigning a trunk port to a VLAN ························································································ 143
Assigning a hybrid port to a VLAN······················································································· 144
Displaying and maintaining VLANs ···························································································· 145
Port-based VLAN configuration example····················································································· 145
Network requirements ······································································································ 145
Configuration procedure ··································································································· 145
Verifying the configuration ································································································· 146
Configuring VLAN mapping ···························································· 147
Overview······························································································································ 147
VLAN mapping application scenarios··················································································· 147
VLAN mapping implementations ························································································· 149
VLAN mapping configuration task list ························································································· 152
Configuring one-to-one VLAN mapping······················································································· 153
Configuring one-to-two VLAN mapping ······················································································· 153
Configuring zero-to-two VLAN mapping ······················································································ 154
Configuring two-to-two VLAN mapping ······················································································· 155
Configuring two-to-three VLAN mapping ····················································································· 156
Displaying and maintaining VLAN mapping ················································································· 156
VLAN mapping configuration examples ······················································································ 157
One-to-one VLAN mapping configuration example ································································· 157
One-to-two and two-to-two VLAN mapping configuration example ············································· 159
Configuring LLDP········································································· 163
Overview······························································································································ 163
Basic concepts ··············································································································· 163
Working mechanism ········································································································ 168
Protocols and standards ··································································································· 169
LLDP configuration task list ······································································································ 169
Performing basic LLDP configurations ························································································ 170
Enabling LLDP················································································································ 170
Setting the LLDP bridge mode ··························································································· 170
Setting the LLDP operating mode ······················································································· 171
Setting the LLDP reinitialization delay ·················································································· 171
Enabling LLDP polling ······································································································ 171
Configuring the advertisable TLVs ······················································································ 172
Configuring the management address and its encoding format·················································· 174
Setting other LLDP parameters ·························································································· 175
Setting an encapsulation format for LLDP frames ··································································· 176
Disabling LLDP PVID inconsistency check············································································ 177
Configuring CDP compatibility ·································································································· 177
Configuration prerequisites································································································ 177
Configuration procedure ··································································································· 178
Configuring DCBX·················································································································· 178
DCBX configuration task list ······························································································ 179
Enabling LLDP and DCBX TLV advertising ··········································································· 179
Setting the DCBX version·································································································· 180
Configuring ETS parameters······························································································ 180
Configuring PFC parameters ····························································································· 182
Configuring LLDP trapping and LLDP-MED trapping······································································ 182
Setting the source MAC address of LLDP frames ········································································· 183
Enabling the device to generate ARP or ND entries for received management address LLDP TLVs ········ 184
Displaying and maintaining LLDP ······························································································ 184
Basic LLDP configuration example ···························································································· 185
Network requirements ······································································································ 185
Configuration procedure ··································································································· 185
Verifying the configuration ································································································· 186
vi
Configuring service loopback groups ················································ 190
Configuration procedure ·········································································································· 190
Displaying and maintaining service loopback groups ····································································· 190
Service loopback group configuration example············································································· 191
Network requirements ······································································································ 191
Configuration procedure ··································································································· 191
Index ························································································· 192
1
Configuring Ethernet interfaces
The Switch Series supports Ethernet interfaces, management Ethernet interfaces, Console
interfaces, and USB interfaces. For the interface types and the number of interfaces supported by a
switch model, see the installation guide.
This chapter describes how to configure management Ethernet interfaces and Ethernet interfaces.
Ethernet interface naming conventions
For a switch in an IRF fabric, its Ethernet interfaces are numbered in the format of interface type
A/B/C/D. For a switch not in an IRF fabric, its Ethernet interfaces are numbered in the format of
interface type B/C/D. The following definitions apply:
•A—IRF member ID.
•B—Slot number of the card in the switch.
•C—Sub-slot number on a card.
•D—Number of an interface on a card.
Configuring a management Ethernet interface
A management interface uses an RJ-45 connector. You can connect the interface to a PC for
software loading and system debugging, or connect it to a remote NMS for remote system
management.
To configure a management Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter management
Ethernet interface view.
interface
M-GigabitEthernet
interface-number
N/A
3. (Optional.) Set the
interface description. description text The default setting is
M-GigabitEthernet0/0/0 Interface.
4. (Optional.) Shut down
the interface. shutdown By default, the management Ethernet
interface is up.
NOTE:
Set the same speed and duplex mode for a management Ethernet interface and its peer port.
Configuring common Ethernet interface settings
This section describes the settings common to Layer 2 Ethernet interfaces, Layer 3 Ethernet
interfaces, and Layer 3 Ethernet subinterfaces. For more information about the settings specific to
Layer 2 Ethernet interfaces or subinterfaces, see "Configuring a Layer 2 Ethernet interface." For
more information about the settings specific to Layer 3 Ethernet interfaces or subinterfaces, see
"Configuring a Layer 3 Ethernet interface or subinterface."
2
Splitting a 40-GE interface and combining 10-GE breakout
interfaces
Configuration restrictions and guidelines
All interfaces on the LSXM1CGQ6QGHB1, LSXM1CGQ18QGHB1, LSXM1CGQ18QGHF1, and
LSXM1CGQ36HB1 interface modules can be split into four breakout interfaces.
100-GE interfaces on the LSXM1TGS48C2HB1 interface modules cannot be split into four breakout
interfaces.
Interfaces numbered 1 through 4, 17 through 22, 35, and 36 on LSXM1QGS36HB1 interface
modules can be split into four breakout interfaces.
Interfaces numbered 1 through 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, and 46 on
LSXM1QGS48HB1 interface modules can be split into four breakout interfaces.
Splitting a 40-GE interface into four 10-GE breakout interfaces
As a best practice for the long-term system stabilization, reboot the device after configuration.
You can use a 40-GE interface as a single interface. To improve port density, reduce costs, and
improve network flexibility, you can also split a 40-GE interface into four 10-GE breakout interfaces.
For example, you can split 40-GE interface FortyGigE 1/0/1 into four 10-GE breakout interfaces
Ten-GigabitEthernet 1/0/1:1 through Ten-GigabitEthernet 1/0/1:4.
A 40-GE interface split into four 10-GE breakout interfaces must use a dedicated 1-to-4 cable. For
more information about the cable, see the installation guides.
The 10-GE breakout interfaces support the same configuration and attributes as common 10-GE
interfaces, except that they are numbered in a different way.
After the using tengige command is successfully configured, you can view the four 10-GE breakout
interfaces by using the display interface brief command.
To split a 40-GE interface into four 10-GE breakout interfaces:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter 40-GE interface view. interface interface-type
interface-number N/A
3. Split the 40-GE interface into
four 10-GE breakout
interfaces. using tengige By default, a 40-GE interface is not
split and operates as a single
interface.
Combining four 10-GE breakout interfaces into a 40-GE interface
As a best practice for the long-term system stabilization, reboot the device after configuration.
If you need higher bandwidth on a single interface, you can combine the four 10-GE breakout
interfaces into a 40-GE interface.
After you combine the four 10-GE breakout interfaces, replace the dedicated 1-to-4 cable with a
dedicated 1-to-1 cable or a 40-GE transceiver module. For more information about the cable or
transceiver module, see the installation guides.
After the using fortygige command is successfully configured, you can view the 40-GE interface by
using the display interface brief command.
To combine four 10-GE breakout interfaces into a 40-GE interface:
3
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter the view of any 10-GE
breakout interface. interface interface-type
interface-number N/A
3. Combine the four 10-GE
breakout interfaces into a
40-GE interface. using fortygige By default, a 10-GE breakout
interface operates as a single
interface.
Configuring basic settings of an Ethernet interface or
subinterface
You can configure an Ethernet interface to operate in one of the following duplex modes:
•Full-duplex mode—The interface can send and receive packets simultaneously.
•Autonegotiation mode—The interface negotiates a duplex mode with its peer.
You can set the speed of an Ethernet interface or enable it to automatically negotiate a speed with its
peer.
Configuring an Ethernet interface
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Set the description for
the Ethernet interface. description text
The default setting is interface-name
Interface. For example,
HundredGigE1/0/1 Interface.
4. Set the duplex mode for
the Ethernet interface. duplex { auto | full } By default, the duplex mode is auto for
Ethernet interfaces.
5. Set the speed for the
Ethernet interface. speed { 1000 | 10000 | 40000 |
100000 | auto }
The default setting is auto for Ethernet
interfaces.
Support for the keywords depends on the
interface type. For more information, use
the speed ? command in interface view.
6. Set the expected
bandwidth for the
Ethernet interface. bandwidth bandwidth-value By default, the expected bandwidth (in
kbps) is the interface baud rate divided by
1000.
7. Restore the default
settings for the Ethernet
interface. default N/A
8. Bring up the Ethernet
interface. undo shutdown
By default, Ethernet interfaces are in
down state.
The loopback, shutdown, and port
up-mode commands are mutually
exclusive.
Configuring an Ethernet subinterface
Step Command Remarks
1. Enter system view. system-view N/A
4
Step Command Remarks
2. Create an Ethernet
subinterface. interface interface-type
interface-number.subnumber N/A
3. Set the description for the
Ethernet subinterface. description text
The default setting is
interface-name Interface. For
example, HundredGigE1/0/1.1
Interface.
4. Restore the default settings
for the Ethernet subinterface. default N/A
5. Set the expected bandwidth
for the Ethernet subinterface. bandwidth bandwidth-value
By default, the expected
bandwidth (in kbps) is the
interface baud rate divided by
1000.
6. Bring up the Ethernet
subinterface. undo shutdown
By default, Ethernet subinterfaces
are in down state.
The shutdown and port
up-mode commands are mutually
exclusive.
Configuring the link mode of an Ethernet interface
CAUTION:
After you change the link mode of an Ethernet interface, all commands (except the shutdown
command) on the Ethernet interface are restored to their defaults in the new link mode.
The interfaces on this Switch Series can operate either as Layer 2 or Layer 3 Ethernet interfaces.
You can set the link mode to bridge or route.
You might fail to change the link mode of an Ethernet interface because of conflicting configurations
on the interface. To solve this problem, manually delete all configurations of the interface and change
the link mode again.
To configure the link mode of an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Configure the link mode of
the Ethernet interface. port link-mode { bridge | route } By default, Ethernet interfaces
operate in bridge mode.
Configuring jumbo frame support
An Ethernet interface might receive frames larger than the standard Ethernet frame size during
high-throughput data exchanges, such as file transfers. These frames are called jumbo frames.
The Ethernet interface processes jumbo frames in the following ways:
•When the Ethernet interface is configured to deny jumbo frames, the Ethernet interface
discards jumbo frames.
•When the Ethernet interface is configured with jumbo frame support, the Ethernet interface
performs the following operations:
5
{Processes jumbo frames within the specified length.
{Discards jumbo frames that exceed the specified length.
To configure jumbo frame support in interface view:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Configure jumbo frame
support. jumboframe enable [ size ]
By default, the switch allows jumbo
frames within 12288 bytes to pass
through all Ethernet interfaces.
Configuring physical state change suppression on an
Ethernet interface
IMPORTANT:
Do not enable this feature on an interface that has RRPP, spanning tree protocols, or Smart Link
enabled.
The physical link state of an Ethernet interface is either up or down. Each time the physical link of an
interface comes up or goes down, the interface immediately reports the change to the CPU. The
CPU then performs the following operations:
•Notifies the upper-layer protocol modules (such as routing and forwarding modules) of the
change for guiding packet forwarding.
•Automatically generates traps and logs to inform users to take the correct actions.
To prevent frequent physical link flapping from affecting system performance, configure physical
state change suppression. You can configure this feature to suppress only link-down events, only
link-up events, or both. If an event of the specified type still exists when the suppression interval
expires, the system reports the event.
When you configure this feature, follow these guidelines:
•To suppress only link-down events, configure the link-delay [ msec ] delay-time command.
•To suppress only link-up events, configure the link-delay [ msec ] delay-time mode up
command.
•To suppress both link-down and link-up events, configure the link-delay [ msec ] delay-time
mode updown command.
To configure physical state change suppression on an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet
interface view. interface interface-type
interface-number N/A
3. Configure physical
state change
suppression.
link-delay [ msec ]
delay-time [ mode { up |
updown }]
By default, the link-down or link-up event is
immediately reported to the CPU.
If you configure this command multiple times on
an Ethernet interface, the most recent
configuration takes effect.
6
Configuring dampening on an Ethernet interface
The interface dampening feature uses an exponential decay mechanism to prevent excessive
interface flapping events from adversely affecting routing protocols and routing tables in the network.
Suppressing interface state change events protects the system resources.
If an interface is not dampened, its state changes are reported. For each state change, the system
also generates an SNMP trap and log message.
After a flapping interface is dampened, it does not report its state changes to the CPU. For state
change events, the interface only generates SNMP trap and log messages.
Parameters
•Penalty—The interface has an initial penalty of 0. When the interface flaps, the penalty
increases by 1000 for each down event until the ceiling is reached. It does not increase for up
events. When the interface stops flapping, the penalty decreases by half each time the half-life
timer expires until the penalty drops to the reuse threshold.
•Ceiling—The penalty stops increasing when it reaches the ceiling.
•Suppress-limit—The accumulated penalty that triggers the device to dampen the interface. In
dampened state, the interface does not report its state changes to the CPU. For state change
events, the interface only generates SNMP traps and log messages.
•Reuse-limit—When the accumulated penalty decreases to this reuse threshold, the interface is
not dampened. Interface state changes are reported to the upper layers. For each state change,
the system also generates an SNMP trap and log message.
•Decay—The amount of time (in seconds) after which a penalty is decreased.
•Max-suppress-time—The maximum amount of time the interface can be dampened. If the
penalty is still higher than the reuse threshold when this timer expires, the penalty stops
increasing for down events. The penalty starts to decrease until it drops below the reuse
threshold.
The ceiling is equal to 2(Max-suppress-time/Decay) × reuse-limit. It is not user configurable.
Figure 1 shows the change rule of the penalty value. The lines t0and t2indicate the start time and
end time of the suppression, respectively. The period from t0to t2indicates the suppression period, t0
to t1indicates the max-suppress-time, and t1to t2indicates the complete decay period.
7
Figure 1 Change rule of the penalty value
Configuration restrictions and guidelines
When you configure dampening on an Ethernet interface, follow these restrictions and guidelines:
•The dampening command and the link-delay command cannot be configured together on an
interface.
•The dampening command does not take effect on the administratively down events. When you
execute the shutdown command, the penalty restores to 0, and the interface reports the down
event to the upper-layer protocols.
•Do not enable the dampening feature on an interface with RRPP, MSTP, or Smart Link enabled.
Configuration procedure
To configure dampening on an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet
interface view. interface interface-type
interface-number N/A
3. Enable dampening on
the interface. dampening [half-life reuse
suppress max-suppress-time ]By default, interface dampening is
disabled on Ethernet interfaces.
Enabling loopback testing on an Ethernet interface
CAUTION:
After you enable this feature on an Ethernet interface, the interface cannot forward data traffic
correctly.
Perform this task to determine whether an Ethernet link works correctly.
8
Loopback testing includes the following types:
•Internal loopback testing—Tests the device where the Ethernet interface resides. The
Ethernet interface sends outgoing packets back to the local device. If the device fails to receive
the packets, the device fails.
•External loopback testing—Tests the inter-device link. The Ethernet interface sends incoming
packets back to the remote device. If the remote device fails to receive the packets, the
inter-device link fails.
Configuration restrictions and guidelines
•On an administratively shut down Ethernet interface (displayed as in ADM or Administratively
DOWN state), you cannot perform an internal or external loopback test.
•The speed, duplex, and shutdown commands are not available during a loopback test.
•A loopback test cannot be performed on an interface configured with the port up-mode
command.
•During a loopback test, the Ethernet interface operates in full duplex mode. When a loopback
test is complete, the port returns to its duplex setting..
Configuration procedure
To enable loopback testing on an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Enable loopback testing. loopback { external | internal } By default, no loopback test is
performed.
Configuring generic flow control on an Ethernet interface
To avoid dropping packets on a link, you can enable generic flow control at both ends of the link.
When traffic congestion occurs at the receiving end, the receiving end sends a flow control (Pause)
frame to ask the sending end to suspend sending packets. Generic flow control includes the
following types:
•TxRx-mode generic flow control—Enabled by using the flow-control command. With
TxRx-mode generic flow control enabled, an interface can both send and receive flow control
frames:
{When congestion occurs, the interface sends a flow control frame to its peer.
{When the interface receives a flow control frame from its peer, it suspends sending packets
to its peer.
•Rx-mode generic flow control—Enabled by using the flow-control receive enable
command. With Rx-mode generic flow control enabled, an interface can receive flow control
frames, but it cannot send flow control frames:
{When congestion occurs, the interface cannot send flow control frames to its peer.
{When the interface receives a flow control frame from its peer, it suspends sending packets
to its peer.
To handle unidirectional traffic congestion on a link, configure the flow-control receive enable
command at one end and the flow-control command at the other end. To enable both ends of a link
to handle traffic congestion, configure the flow-control command at both ends.
This feature is mutually exclusive with PFC.
9
To enable generic flow control on an Ethernet interface:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Ethernet interface
view. interface interface-type
interface-number N/A
3. Enable generic flow
control.
•Enable TxRx-mode
generic flow control:
flow-control
•Enable Rx-mode generic
flow control:
flow-control receive
enable
By default, generic flow control is
disabled on an Ethernet interface.
Configuring PFC on an Ethernet interface
When congestion occurs in the network, the local device notifies the peer to stop sending packets
carrying the specified 802.1p priority if all of the following conditions exist:
•Both the local end and the remote end have PFC enabled.
•Both the local end and the remote end have the priority-flow-control no-drop dot1p
command configured.
•The specified 802.1p priority is in the 802.1p priority list specified by the dot1p-list argument.
•The local end receives a packet carrying the specified 802.1p priority.
The state of the PFC feature is determined by the PFC configuration on the local end and on the peer
end. In Table 1:
•The first row lists the PFC configuration on the local interface.
•The first column lists the PFC configuration on the peer.
•The Enabled and Disabled fields in other cells are possible negotiation results.
Make sure all interfaces that a data flow passes through have the same PFC configuration.
Table 1 PFC configurations and negotiation results
Local (right)
Peer (below) enable auto Default
enable Enabled Enabled. Disabled
auto Enabled
•Enabled if negotiation
succeeds.
•Disabled if negotiation fails.
Disabled
Default Disabled Disabled. Disabled
Configuration restrictions and guidelines
When you configure PFC, follow these restrictions and guidelines:
•For IRF and other protocols to operate correctly, as a best practice, do not enable PFC for
802.1p priorities 0, 6, and 7.
•To avoid packet loss, apply the same PFC configuration to all interfaces that the packets pass
through.
•If you do not enable PFC on an interface, the interface can receive but cannot process PFC
pause frames. To make PFC take effect, you must enable PFC on both ends.
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