H3C S5510 Series Operating instructions

Operation Manual – Link Aggregation

H3C S3610&S5510 Series Ethernet Switches Table of Contents

Table of Contents

Chapter 1 Link Aggregation Overview........................................................................................1-1

1.1 Link Aggregation................................................................................................................1-1

1.1.1 LACP.......................................................................................................................1-1

1.1.2 Consistency Considerations for Ports in an Aggregation .......................................1-1

1.2 Approaches to Link Aggregation........................................................................................1-3

1.2.1 Manual Link Aggregation ........................................................................................1-3

1.2.2 Static LACP link aggregation ..................................................................................1-4

1.3 Load Sharing in a Link Aggregation Group .......................................................................1-5

1.4 Service Loop Group...........................................................................................................1-6

1.5 Aggregation Port Group.....................................................................................................1-7

Chapter 2 Link Aggregation Configuration ................................................................................2-1

2.1 Configuring Link Aggregation ............................................................................................2-1

2.1.1 Configuring a Manual Link Aggregation Group.......................................................2-1

2.1.2 Configuring a Static LACP Link Aggregation Group...............................................2-2

2.1.3 Configuring an Aggregation Group Name...............................................................2-3

2.1.4 Configuring a Service Loop Group..........................................................................2-3

2.1.5 Entering Aggregation Port Group View...................................................................2-4

2.2 Displaying and Maintaining Link Aggregation.................................................................... 2-4

2.3 Link Aggregation Configuration Example..........................................................................2-5

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Chapter 1 Link Aggregation Overview

This chapter covers these topics:

z Link Aggregation

z Approaches to Link Aggregation

z Load Sharing in a Link Aggregation Group

z Service Loop Group

z Aggregation Port Group

1.1 Link Aggregation

Link aggregation allows you to increase bandwidth by distributing incoming/outgoing

traffic on the member ports in an aggregation group. In addition, it provides reliable

connectivity because these member ports can dynamically back up each other.

1.1.1 LACP

Link Aggregation Control Protocol (LACP) is defined in IEEE 802.3ad. Link aggregation

control protocol data unit (LACPDU) is used for exchanging information among

LACP-enabled devices.

After LACP is enabled on a port, the port sends LACPDUs to notify the remote system

of its system LACP priority, system MAC address, port LACP priority, port number, and

operational key. Upon receipt of an LACPDU, the remote system compares the

received information with the information received on other ports to determine the ports

that can operate as selected ports. This allows the two systems to reach agreement on

the states of the related ports

When aggregating ports, link aggregation control automatically assigns each port an

operational key based on its rate, duplex mode, and other basic configurations. In an

LACP aggregation group, all ports share the same operational key; in a manual or static

LACP aggregation, the selected ports share the same operational key.

1.1.2 Consistency Considerations for Ports in an Aggregation

To participate in traffic sharing, member ports in an aggregation group must use the

same configurations with respect to STP, QoS, GVRP, Q-in-Q, BPDU tunnel, VLAN,

port attributes, MAC address learning, and so on as shown in the following table.

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Table 1-1 Consistency considerations for ports in an aggregation

Category Considerations

STP

State of port-level STP (enabled or disabled)

Attribute of the link (point-to-point or otherwise) connected to the

port

Port path cost

STP priority

Maximum transmission rate

Loop protection

Root protection

Port type (whether the port is an edge port)

QoS

Traffic policing

Traffic shaping

Congestion avoidance

Port rate limiting

Strict priority (SP) queuing

Weighted round robin (WRR) queuing

Weighted fair queuing (WFQ)

Port priority

Port trust mode

GVRP

GVRP state on ports (enabled or disabled)

GVRP registration type

GARP timers

Q-in-Q

State of Q-in-Q (enabled or disabled)

Added outer VLAN tag

Policy of appending outer VLAN tag according to inner VLAN IDs

BPDU tunnel

BPDU tunnel state on ports (enabled or disabled)

BPDU tunnel state for STP on ports (enabled or disabled)

VLAN

VLANs carried on the port

Default VLAN ID on the port

Link type of the port, which can be trunk, hybrid, or access

sub-net VLAN configuration

protocol VLAN configuration

VLAN tag configuration

Port attribute

Port rate

Duplex mode

Up/down state of the link

Isolation group membership of the port

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Category Considerations

MAC address

learning

MAC address learning capability

Setting of maximum number of MAC addresses that can be

learned on the port

Forwarding of frames with unknown destination MAC addresses

after the upper limit of the MAC address table is reached

1.2 Approaches to Link Aggregation

Two ways are available for implementing link aggregation, as described in Manual Link

Aggregation

and Static LACP link aggregation.

1.2.1 Manual Link Aggregation

I. Overview

Manual aggregations are created manually. Member ports in a manual aggregation are

LACP-disabled.

II. Port states in a manual aggregation

In a manual aggregation group, ports are either selected or unselected. Selected ports

can receive and transmit data frames whereas unselected ones cannot.

When setting the state of ports in a manual aggregation group, the system considers

the following:

z The system selects the port with the highest priority in the up state as the

reference port of the aggregation group. Port priority descends in the following

order: full duplex/high speed, full duplex/low speed, half duplex/high speed, and

half duplex/low speed. If multiple ports are of the same priority, the one with the

lowest port number is the reference port.

z Ports in the up state with the same speed, duplex mode, link state, and basic

configuration as the reference port become the candidates for selected ports,

while the other ports become unselected ports.

z There is a limit on the number of selected ports in a manual aggregation group. If

the number of selected-port candidates does not reach the limit, all the candidates

become selected ports; if the number of candidates exceeds the limit, the

candidates with lower port numbers become selected ports, while the other

candidates become unselected ports.

z The selected port with the lowest port number serves as the master port of the

aggregation group, and the other ports serve as the member ports of the

aggregation group.

z If all the ports of an aggregations port are down, the port with the lowest port

number is the master port. In this case, all of them are unselected ports.

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In addition, unless the master port should be selected, a port that joins the group after

the limit is reached will not be placed in selected state even if it should be in normal

cases. This is to prevent the ongoing service on selected ports from being interrupted.

You need to avoid the situation however as the selected/unselected state of a port may

become different after a reboot.

III. Port Configuration Considerations in manual aggregation

As mentioned above, in a manual aggregation group, only ports with configurations

consistent with those of the reference port can become selected. These configurations

include port rate, duplex mode, link state, and other basic configurations, as described

Consistency Considerations for Ports in an Aggregation.

You need to maintain the basic configurations of these ports manually to ensure

consistency. As one configuration change may involve multiple ports, this can become

troublesome if you need to do that port by port. As a solution, you may add the ports

into an aggregation port group where you can make configuration for all member ports.

When the configuration of some port in a manual aggregation group changes, the

system does not remove the aggregation; instead, it re-sets the selected/unselected

state of the member ports and re-selects a master port.

1.2.2 Static LACP link aggregation

I. Overview

Static aggregations are created manually. After you add a port to a static aggregation,

LACP is enabled on it automatically.

II. Port states in static aggregation

In a static aggregation group, ports can be selected or unselected, where both can

receive and transmit LACPDUs but only selected ports can receive and transmit data

frames.

When setting the state of the ports in the local and remote static aggregation groups,

the local and remote systems do the following:

1) Compare their system IDs to identify the higher priority system. (The system ID

comprises LACP priority and system MAC address.)

z First compare the system LACP priorities. The system with lower system LACP

priority wins out.

z If the system LACP priorities are the same, compare the system MAC addresses.

The system with the smaller MAC address wins out.

2) Compare the port IDs on the higher priority system. (The port ID comprises port

LACP priority and port number.)

z Compare the port LACP priorities. The port with lower port LACP priority wins out.

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z If two ports with the same port LACP priority are present, compare their port

numbers. The one with the smaller port ID wins out to become the reference port.

3) Select the candidates for selected ports. To be a candidate, a port must be in the

up state with the same speed, duplex mode, link state, and basic configuration as

the reference port; in addition, their peer ports on the other system must have the

same configuration. All the ports but the selected-port candidates become

unselected.

4) As there is a limit on the number of selected ports, not all selected-port candidates

can become selected ports. Before the limit is reached, all the candidates are set

to the selected state. When the limit is reached, the candidates with lower port

numbers are set to the selected state while the other candidates are set to the

unselected state. At the same time, the other system gets aware of the state

change of the ports on the higher priority system and thus sets the state of the

corresponding local ports.

5) Set the selected port with the lowest port number as the master port in the

aggregation group on each system.

III. Port configuration considerations in static aggregation

Like in a manual aggregation group, in a static LACP aggregation group, only ports with

configurations consistent with those of the reference port can become selected. These

configurations include port rate, duplex mode, link state and other basic configurations

described in

Consistency Considerations for Ports in an Aggregation.

You need to maintain the basic configurations of these ports manually to ensure

consistency. As one configuration change may involve multiple ports, this can become

troublesome if you need to do that port by port. As a solution, you may add the ports

into an aggregation port group where you can make configuration for all member ports.

When the configuration of some port in a static aggregation group changes, the system

does not remove the aggregation; instead, it re-sets the selected/unselected state of

the member ports and re-selects a master port.

1.3 Load Sharing in a Link Aggregation Group

A link aggregation group can be load sharing or non-load sharing, depending on the

availability of aggregation resources when the group is created.

z When aggregation resources are available, the group is a load sharing

aggregation group if it contains selected port(s).

z If all aggregation resources are used up, the group is a non-load sharing

aggregation group.

With load sharing enabled, traffic is distributed on the selected ports in the aggregation

group. However, the way of selecting forwarding ports varies by packet type:

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z For a known Layer 2 unicast packet, the switch selects the forwarding port based

on the least significant six bits in the source MAC address and the least significant

six bits in the destination MAC address.

z For a unicast IP packet with the destination MAC address being known, the switch

selects the forwarding port based on the lower order 6 bits in the source MAC

address, the lower order 6 bits in the destination MAC address, the lower order 6

bits in the source IP address, the lower order bits 16 through 21 in the source IP

address, the lower order 6 bits in the destination IP address, and the lower order

bits 16 through 21 in the destination IP address.

z For a broadcast/multicast/unknown unicast packet, the switch selects the

forwarding port based on its VLAN ID, source port ID, and source device ID.

Caution:

The arrived broadcasts/multicasts/unknown unicasts may be distributed over different

selected ports if they have different VLAN IDs, source ports, or source devices; if they

are only different in source MAC address, they are forwarded out the same port.

1.4 Service Loop Group

You can create a service loop group by creating a manual aggregation group of

service-loop ports first and then specifying which services can be redirected for the

group. At present, you may specify to redirect four types of services, IPv6 (IPv6 unicast),

IPv6mc (IPv6 multicast), tunnel, and MPLS.

 Note:

Currently, the S3610&S5510 series Ethernet switches support to redirect tunnel

services only.

After creating a service-loop group, assign ports that support its service type to the

group considering the following:

z These ports can be configured only with the physical configuration such as speed

and duplex mode, QoS, and ACL. Other conflicting configurations, such as STP

cannot be configured.

z These ports must belong to VLAN 1.

After assigning a port to a service-loop group, you may configure it with other

non-conflicting settings, such as QoS.

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If this group is performing load sharing, it continues to function in this way even after all

selected ports but one are removed to ensure ongoing service.

1.5 Aggregation Port Group

As mentioned earlier, in a manual or static aggregation group, a port can be selected

only when its configuration is the same as that of the reference port in terms of

duplex/speed pair, link state, and other basic configurations. Their configuration

consistency requires administrative maintenance, which is troublesome after you

change some configuration.

To simplify configuration, port-groups are provided allowing you to configure for all ports

in individual groups at one time. One example of port-groups is aggregation port group.

Upon creation or removal of a link aggregation group, an aggregation port-group which

cannot be administratively created or removed is automatically created or removed. In

addition, you can only assign/remove a member port to/from an aggregation port-group

by assigning/removing it from the corresponding link aggregation group.

For more information about port-groups, refer to Port Correlation Configuration.

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Chapter 2 Link Aggregation Configuration

When configuring link aggregation, go to these sections for information you are

interested in:

z Configuring Link Aggregation

z Displaying and Maintaining Link Aggregation

z Link Aggregation Configuration Example

2.1 Configuring Link Aggregation

This section covers these topics:

z Configuring a Manual Link Aggregation Group

z Configuring a Static LACP Link Aggregation Group

z Configuring an Aggregation Group Name

z Configuring a Service Loop Group

z Entering Aggregation Port Group View

2.1.1 Configuring a Manual Link Aggregation Group

Follow these steps to create a manual aggregation group and add an Ethernet port to it:

To do… Use the command… Remarks

Enter system view

system-view

––

Create a manual

aggregation group

link-aggregation group agg-id

mode manual

Required

Enter Ethernet port view

interface interface-type

interface-number

––

Assign the Ethernet port

to the aggregation group

port link-aggregation group

agg-id

Required

Note that:

z You can create a manual aggregation group by changing the type of an existing

static aggregation group. When you create a manual aggregation group in this

way and the static aggregation group contains ports, LACP is disabled on the ports

after the manual aggregation group is created.

z An aggregation group cannot contain the following ports: RRPP-enabled ports,

reflector ports or destination ports of port mirroring groups, ports with static MAC

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addresses or black hole MAC addresses configured, voice VLAN-enabled ports,

or 802.1x-enabled ports.

z After you remove a manual aggregation group, all the ports in the group are

dismissed from it.

z For a manual aggregation group containing only one port, the only way to remove

the port from it is to remove the aggregation group.

z To make an aggregation group function properly, make sure that the

selected/unselected state of the ports at both ends of a link is consistent.

2.1.2 Configuring a Static LACP Link Aggregation Group

Follow these steps to configure a static aggregation group:

To do… Use the command… Remarks

Enter system view

system-view

––

Configure the system

LACP priority

lacp system-priority

system-priority

Optional

32768 by default.

Changing system LACP

priority can affect the

selected/unselected state

of the ports in the group.

Create a static LACP

aggregation group

link-aggregation group

agg-id mode static

Required

Enter Ethernet port view

interface interface-type

interface-number

––

Configure the port LACP

priority

lacp port-priority

port-priority

Optional

32768 by default.

Changing port LACP

priority can affect the

selected/unselected state

of the ports in the group.

Assign the Ethernet port

to the aggregation group

port link-aggregation

group agg-id

Required

Note that:

z You can create a static aggregation group by changing the type of an existing

manual link aggregation group that contains no port.

z An aggregation group cannot contain the following ports: RRPP-enabled ports,

reflector ports or destination ports of port mirroring groups, ports configured with

static MAC addresses or black hole MAC addresses, voice VLAN-enabled ports,

or 802.1x-enabled ports.

z After you remove a static aggregation group, all the ports in the group are

dismissed from it, and LACP is disabled on the ports.

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z For a static LACP aggregation group containing only one port, the only way to

remove the port from the aggregation group is to remove the aggregation group.

 Note:

When making configuration, be aware that after a load-balancing aggregation group

changes to a non-load balancing group due to resources exhaustion, either of the

following may happen:

z Forwarding anomaly resulted from inconsistency of the two ends in the number of

selected ports.

z Some protocols such as GVRP malfunction because the state of the remote port

connected to the master port is unselected.

2.1.3 Configuring an Aggregation Group Name

Follow these steps to configure a name for an aggregation group:

To do… Use the command… Remarks

Enter system view

system-view

––

Configure a name for a

link aggregation group

link-aggregation group

agg-id description

agg-name

Required

None is configured by

default.

2.1.4 Configuring a Service Loop Group

Follow these steps to configure a service loop group:

To do… Use the command… Remarks

Enter system view

system-view

––

Create a manual

aggregation group

link-aggregation group agg-id

mode manual

Required

Specify the aggregation

group as a service loop

group that is of specific

type

link-aggregation group agg-id

service-type tunnel

Required

Enter Ethernet port view

interface interface-type

interface-number

––

Add the Ethernet port to

the aggregation group

port link-aggregation group

agg-id

Required

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 Note:

z You can remove any service loop group except those that are currently referenced

by modules.

z For a service loop group containing only one port, the only way to remove the port

from it is to remove the service loop group.

2.1.5 Entering Aggregation Port Group View

In aggregation port group view, you can make configuration for all the member ports in

a link aggregation group at one time.

Follow these steps to enter aggregation port group view:

To do… Use the command… Remarks

Enter system view

system-view

––

Enter aggregation port group

view

port-group aggregation

agg-id

––

Caution:

In aggregation port group view, you can configure aggregation related settings such as

STP, VLAN, QoS, GVRP, Q-in-Q, BPDU tunnel, MAC address learning, but cannot add

or remove member ports.

2.2 Displaying and Maintaining Link Aggregation

To do… Use the command… Remarks

Display the local system

display lacp system-id

Available in any

view

Display detailed

information about link

aggregation for the

specified port or ports

display link-aggregation

interface interface-type

interface-number [ to interface-type

interface-number ]

Available in any

view

Display information about

the specified or all service

loop groups

display link-aggregation

service-type [ agg-id ]

Available in any

view

Display summaries for all

link aggregation groups

display link-aggregation

summary

Available in any

view

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To do… Use the command… Remarks

Display detailed

information about

specified or all link

aggregation groups

display link-aggregation verbose

[ agg-id ]

Available in any

view

Clear the statistics about

LACP for specified or all

ports

reset lacp statistics [ interface

interface-type interface-number [ to

interface-type interface-number ] ]

Available in user

view

2.3 Link Aggregation Configuration Example

I. Network requirements

Device A aggregates ports Ethernet 1/0/1 through Ethernet 1/0/3 to form one link

connected to Device B and performs load sharing among these ports.

Create a tunnel service-loop group and add port Ethernet 1/0/1 to the group.

II. Network diagram

Device A

Link aggregation

Device B

Eth1/0/1

Eth1/0/2

Eth1/0/3

Eth1/0/1

Eth1/0/2

Eth1/0/3

Figure 2-1 Network diagram for link aggregation configuration

III. Configuration procedure

 Note:

This example only describes how to configure link aggregation on Device A. To achieve

link aggregation, do the same on Device B.

1) In manual aggregation approach

# Create manual aggregation group 1.

<DeviceA> system-view

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[DeviceA] link-aggregation group 1 mode manual

# Add ports Ethernet 1/0/1 through Ethernet 1/0/3 to the group.

[DeviceA] interface ethernet 1/0/1

[DeviceA-Ethernet1/0/1] port link-aggregation group 1

[DeviceA-Ethernet1/0/1] interface ethernet 1/0/2

[DeviceA-Ethernet1/0/2] port link-aggregation group 1

[DeviceA-Ethernet1/0/2] interface ethernet 1/0/3

[DeviceA-Ethernet1/0/3] port link-aggregation group 1

2) In static aggregation approach

# Create static aggregation group 1.

<DeviceA> system-view

[DeviceA] link-aggregation group 1 mode static

# Add ports Ethernet 1/0/1 through Ethernet 1/0/3 to the group.

[DeviceA] interface ethernet 1/0/1

[DeviceA-Ethernet1/0/1] port link-aggregation group 1

[DeviceA-Ethernet1/0/1] interface ethernet 1/0/2

[DeviceA-Ethernet1/0/2] port link-aggregation group 1

[DeviceA-Ethernet1/0/2] interface ethernet 1/0/3

[DeviceA-Ethernet1/0/3] port link-aggregation group 1

3) Configure a service loop group

# Create a manual aggregation group.

<DeviceA> system-view

[DeviceA] link-aggregation group 1 mode manual

# Specify this group to be a tunnel service loop group.

[DeviceA] link-aggregation group 1 service-type tunnel

# Assign port Ethernet 1/0/1 to the service loop group.

[DeviceA] interface ethernet 1/0/1

[DeviceA-Ethernet1/0/1] undo stp

[DeviceA-Ethernet1/0/1] port link-aggregation group 1

H3C S5510 Series, S3610 Series Operating instructions

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