Link aggregation means aggregating several
ports together to form an aggregation group, so as to implement
outgoing/incoming load sharing among the member ports in the group and to
enhance the connection reliability.
Depending on different aggregation modes,
aggregation groups fall into three types: manual, static LACP, and dynamic
LACP. Depending on whether or not load sharing is implemented, aggregation
groups can be load-sharing or non-load-sharing aggregation groups.
Up to 384
aggregation groups can be created in a system, where up to 64 load-sharing
aggregation groups can be created.
For the member ports in an aggregation group,
their basic configuration must be the same. The basic configuration includes
STP, QoS, VLAN, port attributes and other associated settings.
l
STP configuration, including STP status (enabled
or disabled), link attribute (point-to-point or not), STP priority, maximum
transmission speed, loop prevention status, root protection status, edge port
or not.
l
QoS configuration, including traffic limiting,
priority marking, default 802.1p priority, bandwidth assurance, congestion
avoidance, traffic redirection, traffic statistics, and so on.
l
VLAN configuration, including permitted VLANs,
and default VLAN ID.
l
Port attribute configuration, including port
rate, duplex mode, and link type (Trunk, Hybrid or Access). The ports for a
manual or static aggregation group must have the same link type, and the ports
for a dynamic aggregation group must have the same rate, duplex mode and link
type.
1.1.2 Introduction to LACP
The purpose of link aggregation control
protocol (LACP) is to implement dynamic link aggregation and deaggregation.
This protocol is based on IEEE802.3ad and uses LACPDUs (link aggregation
control protocol data units) to interact with its peer.
After LACP is enabled on a port, LACP
notifies the following information of the port to its peer by sending LACPDUs:
priority and MAC address of this system, priority, number and operation key of
the port. Upon receiving the information, the peer compares the information
with the information of other ports on the peer device to determine the ports
that can be aggregated with the receiving port. In this way, the two parties
can reach an agreement in adding/removing the port to/from a dynamic
aggregation group.
An operation key of an aggregation port is
a configuration combination generated by system depending on the configurations
of the port (rate, duplex mode, other basic configuration, and management key)
when the port is aggregated.
1)
The selected ports in a manual/static
aggregation group must have the same operation key.
2)
The management key of an LACP-enable static
aggregation port is equal to its aggregation group ID.
3)
The management key of an LACP-enable dynamic
aggregation port is zero by default.
4)
The member ports in a dynamic aggregation group
must have the same operation key.
1.1.4 Manual Aggregation Group
I. Introduction to manual
aggregation group
A manual aggregation group is manually
created. All its member ports are manually added and can be manually removed
(it inhibits the system from automatically adding/removing ports to/from it).
Each manual aggregation group must contain at least one port. When a manual
aggregation group contains only one port, you cannot remove the port unless you
remove the whole aggregation group.
LACP is disabled on the member ports of
manual aggregation groups, and enabling LACP on such a port will not take
effect.
II. Port status in manual
aggregation group
A port in a manual aggregation group can be
in one of the two states: selected or standby. The selected port with the
minimum port number serves as the master port of the group, and other selected
ports serve as member ports of the group.
There is a limit on the number of selected
ports in an aggregation group. Therefore, if the number of the member ports
that can be set as selected ports in an aggregation group exceeds the maximum
number supported by the device, the system will choose the ports with lower
port numbers as the selected ports, and set others as standby ports.
III. Requirements on ports for
manual aggregation
Generally, there is no limit on the rate
and duplex mode of the ports you want to add to a manual aggregation group.
However, the following cases will be processed differently:
l
For the ports which are initially down, there is
no limit on the rate and duplex mode of the ports when they are added to an
aggregation group;
l
For the currently down ports which used to be up
and whose rate and duplex mode are specified in the negotiation mode or
mandatory mode, the rate and duplex mode of each port must be the same as those
of other ports when they are aggregated;
l
When the rate and duplex mode of a port in the
manual aggregation group change, the system does not deaggregate the
aggregation group and all the ports in the group work normally. However, if the
rate of the master port decreases and the duplex mode of the master port changes,
the packets forwarded on the port may be dropped.
1.1.5 Static LACP Aggregation Group
I. Introduction to static LACP
aggregation
A static LACP aggregation group is also
manually created. All its member ports are manually added and can be manually
removed (it inhibits the system from automatically adding/removing ports
to/from it). Each static aggregation group must contain at least one port. When
a static aggregation group contains only one port, you cannot remove the port
unless you remove the whole aggregation group.
LACP is enabled on the member ports of
static aggregation groups, and disabling LACP on such a port will not take
effect. When you remove a static aggregation group, the system will remain the
member ports of the group in LACP-enabled state and re-aggregate the ports to
form one or more dynamic LACP aggregation groups.
II. Port status of static
aggregation group
A port in a static aggregation group can be
in one of the two states: selected or standby. Both the selected and the
standby ports can transceive LACP protocol packets however, the standby ports
cannot forward user packets.
In an
aggregation group, the selected port with the minimum port number serves as the
master port of the group, and other selected ports serve as member ports of the
group.
In a static aggregation group, the system
sets the ports to selected or standby state according to the following rules:
l
The system sets the "most preferred"
ports (that is, the ports take most precedence over other ports) to selected
state, and others to standby state. Port precedence descends in the following
order: full duplex/high speed, full duplex/low speed, half duplex/high speed,
half duplex/low speed.
l
The system sets the following ports to standby
state: ports that are not connected to the same peer device as the master port
(selected port with the minimum port number), and ports that are connected to
the same peer device as the master port but not in the same aggregation group
as the master port.
l
The system sets the ports unable to aggregate
with the master port (due to some hardware limit, for example, cross-board
aggregation unavailability) to standby state.
l
The system sets the ports with basic port
configuration different from that of the master port to standby state.
There is a limit on the number of selected
ports in an aggregation group. Therefore, if the number of the member ports
that can be set as selected ports in an aggregation group exceeds the maximum
number supported by the device, the system will choose the ports with lower
port numbers as the selected ports, and set others as standby ports.
I. Introduction to dynamic LACP
aggregation group
A dynamic LACP aggregation group is
automatically created and removed by the system. Users cannot add/remove ports
to/from it. Ports can be aggregated into a dynamic aggregation group only when
they are connected to the same peer device and have the same basic
configuration (such as rate and duplex mode).
Besides multiple-port aggregation groups,
the system is also able to create single-port aggregation groups, each of which
contains only one port. LACP is enabled on the member ports of dynamic
aggregation groups.
II. Port status of dynamic
aggregation group
A port in a dynamic aggregation group can
be in one of the two states: selected or standby. In a dynamic aggregation group,
both the selected and the standby ports can transceive LACP protocol packets,
however, the standby ports cannot forward user packets.
There is a limit on the number of selected
ports in an aggregation group. Therefore, if the number of the member ports
that can be set as selected ports in an aggregation group exceeds the maximum
number supported by the device, the system will negotiate with its peer end, to
determine the states of the member ports according to the port IDs of the
preferred device (that is, the device with smaller system ID). The following is
the negotiation procedure:
1)
Compare device IDs (system priority + system MAC
address) between the two parties. First compare the two system priorities, then
the two system MAC addresses if the system priorities are equal. The device
with smaller device ID will be considered as the preferred one.
2)
Compare port IDs (port priority + port number)
on the preferred device. The comparison between two port IDs is as follows:
First compare the two port priorities, then the two port numbers if the two
port priorities are equal; the port with the smallest port ID is the selected
port and the left ports are standby ports.
In an aggregation group, the selected port
with the minimum port number serves as the master port of the group, and other
selected ports serve as member ports of the group.
l
The down ports in a static aggregation group or
dynamic aggregation group are standby ports, which is different in manual
aggregation groups.
l
For the restriction of LPU types on link
aggregation, refer to Table 1-2 and Table 1-3.
Table 1-1 lists
link aggregation types and related descriptions.
Type-A LPUs
include the following specifications: LS81FT48A, LS81FM24A, LS81FS24A,
LS81GB8UA and LS81GT8UA.
Table 1-1 Link aggregation types and
related descriptions
|
Aggregation type
|
Basic description
|
Specific description
|
|
Manual aggregation
|
Support up to 384 aggregation groups,
including 64 load sharing aggregation groups
|
l
For type-A LPUs, an aggregation group supports
up to 8 selected GE ports or 16 selected FE ports
l
For non-type-A LPUs, an aggregation group
supports up to 8 selected GE ports or 8 selected FE ports
|
|
Static/dynamic aggregation
|
l
For type-A LPUs, an aggregation group supports
up to 8 selected GE ports
l
For type-A LPUs, an aggregation group supports
up to 24 FE ports, including up to 16 selected ones
l
For non-type-A LPUs, an aggregation group
supports up to 48 ports, including up to 8 selected ones
|
Table 1-2 and Table 1-3 describe the restriction of type-A LPUs and
non-type-A LPUs on link aggregation respectively.
Table 1-2 Restriction
of type-A LPUs on link aggregation
|
LPU type
|
Cross-chip aggregation
|
Aggregation type
|
LPU specification
|
Maximum number of ports in an
aggregation group
|
Maximum number of selected ports
in an aggregation group
|
|
Type-A LPU
|
Not supported
|
Manual aggregation
|
LS81FT48A
|
16
|
16
|
|
LS81FM24A/LS81FS24A
|
16
|
16
|
|
LS81GB8UA/LS81GT8UA
|
8
|
8
|
|
Static/dynamic aggregation
|
LS81FT48A
|
24
|
16
|
|
LS81FM24A/LS81FS24A
|
24
|
16
|
|
LS81GB8UA/LS81GT8UA
|
8
|
8
|
Table 1-3 Restriction
of non-type-A LPUs on link aggregation
|
LPU type
|
Cross-chip aggregation
|
Aggregation type
|
Maximum number of ports in an
aggregation group
|
Maximum number of selected ports
in an aggregation group
|
|
Non-type-A LPU
|
Supported
|
Manual aggregation
|
8
|
8
|
|
Static/dynamic aggregation
|
The number of ports on the LPU
|
8
|
1.1.8 Aggregation Group Categories
Depending on whether or not load sharing is
implemented, aggregation groups can be load-sharing or non-load-sharing
aggregation groups.
In general, the system only provides
limited load-sharing aggregation resources (currently up to 64 load-sharing
aggregation groups can be created), so the system needs to reasonably allocate
the resources among different aggregation groups.
The system always allocates hardware
aggregation resources to the aggregation groups with higher priorities. When
load-sharing aggregation resources are used up by existing aggregation groups,
newly-created aggregation groups will be non-load-sharing ones.
The priorities of aggregation groups for
allocating load-sharing aggregation resources are as follows:
l
An aggregation group containing special ports
(such as 10GE port) which require hardware aggregation resources has higher
priority than any aggregation group containing no special port.
l
A manual or static aggregation group has higher
priority than a dynamic aggregation group (unless the latter contains special
ports while the former does not).
l
For two aggregation groups of the same kind, the
one that might gain higher speed if resources were allocated to it has higher
priority than the other one.
l
If the two groups can gain the same speed after
resources are allocated to them, the one with smaller master port number has
higher priority than the other one.
When an aggregation group of higher
priority appears, the aggregation groups of lower priorities release their
hardware resources. For single-port aggregation groups, if they can transceive
packets normally without occupying aggregation resources, they will not occupy
hardware aggregation resources.
Caution:
A load-sharing
aggregation group contains up to two selected ports, however, a
non-load-sharing aggregation group can only have one selected port at most and
others are standby ports.
Caution:
l
The following ports cannot be added to an
aggregation group: destination ports to be mirrored to, reflection ports to be
remotely mirrored to, ports configured with static MAC addresses,
static-ARP-enabled ports, and 802.1x-enabeld ports.
l
Ports where the IP-MAC address binding is
configured cannot be added to an aggregation group.
You can create a
manual aggregation group, or remove an existing manual aggregation group (after
that, all the member ports in the group are removed from the ports).
You can manually add/remove a port to/from
a manual aggregation group, and a port can only be manually added/removed
to/from a manual aggregation group.
Table 1-4 Configure a manual aggregation group
|
Operation
|
Command
|
Description
|
|
Enter
system view
|
system-view
|
—
|
|
Create a manual aggregation group
|
link-aggregation group agg-id mode manual
|
Required
|
|
Add a group of ports to a new manual
aggregation group
|
link-aggregation interface-type interface-number to interface-type interface-number [ both ]
|
Optional
|
|
Configure a description for the
aggregation group
|
link-aggregation group agg-id description agg-name
|
Optional
By default, an aggregation group has no
description.
|
|
Enter Ethernet port view
|
interface interface-type interface-num
|
—
|
|
Add the port to the aggregation group
|
port
link-aggregation group agg-id
|
Required
|
Note that:
1)
When creating an aggregation group:
l
If the aggregation group you are creating
already exists but contains no port, its type will change to the type you set.
l
If the aggregation group you are creating
already exists and contains ports, the possible type changes may be: changing
from dynamic or static to manual, and changing from dynamic to static; and no
other kinds of type change can occur.
l
When you change a dynamic/static group to a
manual group, the system will automatically disable LACP on the member ports.
When you change a dynamic/static group to a manual group, the system will
remain the member ports LACP-enabled.
2)
When a manual or static aggregation group
contains only one port, you cannot remove the port unless you remove the whole
aggregation group.
You can create a static LACP aggregation
group, or remove an existing static aggregation group (after that, the system
will re-aggregate the original member ports in the group to form one or more
dynamic aggregation groups.).
You can manually add/remove a port to/from
a static aggregation group, and a port can only be manually added/removed
to/from a static aggregation group.
Table 1-5 Configure
a static LACP aggregation group
|
Operation
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Create a static aggregation group
|
link-aggregation group agg-id mode static
|
Required
|
|
Configure a description for the
aggregation group
|
link-aggregation group agg-id description agg-name
|
Optional
By default, an aggregation group has no
description.
|
|
Enter Ethernet port view
|
interface interface-type interface-number
|
—
|
|
Add the port
to the aggregation group
|
port
link-aggregation group agg-id
|
Required
|
For a static
LACP aggregation group or a manual aggregation group, you are recommended not
to cross cables between the two devices at the two ends of the aggregation
group. For example, suppose port 1 of the local device is connected to port 2
of the peer device. To avoid cross-connecting cables, do not connect port 2 of
the local device to port 1 of the peer device. Otherwise, packets may be lost.
Note that:
l
LACP cannot be enabled on an existing port in a
manual aggregation group.
l
You can add a LACP-enabled port to a manual
aggregation group. In this case, the system will disable LACP on the port
automatically. Similarly, when you add a LACP-disabled port to a static
aggregation group, the system will enable LACP on the port automatically.
A dynamic LACP aggregation group is
automatically created by the system based on LACP-enabled ports. The adding and
removing of ports to/from a dynamic aggregation group are automatically
accomplished by LACP.
You need to enable LACP on the ports whom
you want to participate in dynamic aggregation of the system, because, only
when LACP is enabled on those ports at both ends, can the two parties reach
agreement in adding/removing ports to/from dynamic aggregation groups.
Enabling LACP
on a member port of a manual aggregation group will not take effect.
Table 1-6 Configure
a dynamic LACP aggregation group
|
Operation
|
Command
|
Description
|
|
Enter system view
|
system-view
|
—
|
|
Configure a description for an
aggregation group
|
link-aggregation group agg-id description agg-name
|
Optional
By default, an aggregation group has no
description.
|
|
Configure the system priority
|
lacp system-priority system-priority
|
Optional
By default, the system priority is
32,768.
|
|
Enter Ethernet port view
|
interface interface-type interface-number
|
—
|
|
Enable
LACP on the port
|
lacp
enable
|
Required
By
default, LACP is disabled on a port.
|
|
Configure the port priority
|
lacp port-priority port-priority
|
Optional
By default, the port priority is 32,768.
|
l
If an existing aggregation group contains no
port, the type of the aggregation group is set to the latest set type.
l
If an aggregation group contains ports, you can
only change a dynamic aggregation group or static aggregation group into a
manual aggregation group, or change a dynamic aggregation group into a static
aggregation group.
l
When a dynamic aggregation group or a static
aggregation group is changed into a manual aggregation group, the system will
disable LACP on all the member ports automatically. When a dynamic aggregation
group is changed into a static aggregation group, LACP on all the member ports
remains enabled.
Note that if a manual aggregation group or
a static aggregation group contains only one port, this port cannot be removed
from the aggregation group. Instead, it can be removed from the aggregation
group only in the way of removing the aggregation group.
If you use the save
command to save the current configuration and then restart the device, the
configured manual/static aggregation groups and their descriptions still exist,
however, the dynamic aggregation groups will disappear and their descriptions
cannot be restored.
1.3 Displaying and Maintaining Link Aggregation
Configuration
After the above configuration, execute the display
command in any view to display the running status after the link aggregation
configuration and verify your configuration.
Execute the reset command in user
view to clear LACP statistics on ports.
Table 1-7 Display
and maintain link aggregation configuration
|
Operation
|
Command
|
|
Display summary information of all
aggregation groups
|
display link-aggregation summary
|
|
Display detailed information of a
specific aggregation group or all aggregation groups
|
display link-aggregation verbose agg-id
|
|
Display the ID of the local device
|
display lacp system-id
|
|
Display link aggregation details of a
specified port or port range
|
display link-aggregation interface interface-type interface-number | [ to
{ interface-type interface-number ]
|
|
Clear LACP statistics about a specified
port or port range
|
reset lacp statistics [ interface interface-type interface-number [ to
interface-type interface-number ] ]
|
I. Network requirements
l
Switch A connects to Switch B with three ports
Ethernet1/0/1 to Ethernet1/0/3. It is required that incoming/outgoing load
between the two switch can be shared among the three ports.
l
Adopt three different aggregation modes to
implement link aggregation on the three ports between switch A and B.
II. Network diagram
Figure 1-1 Network diagram for link
aggregation configuration
III. Configuration procedure
The following only lists the configuration
on Switch A; you must perform the similar configuration on Switch B to
implement link aggregation.
1)
Adopt the manual aggregation mode
# Create manual aggregation group 1.
<H3C> system-view
System View: return to User View with
Ctrl+Z
[H3C] link-aggregation group 1 mode
manual
# Add Ethernet1/0/1 through Ethernet1/0/3
to aggregation group 1.
[H3C] interface ethernet1/0/1
[H3C-Ethernet1/0/1] port
link-aggregation group 1
[H3C-Ethernet1/0/1] interface
ethernet1/0/2
[H3C-Ethernet1/0/2] port
link-aggregation group 1
[H3C-Ethernet1/0/2] interface
ethernet1/0/3
[H3C-Ethernet1/0/3] port link-aggregation
group 1
2)
Adopt the static LACP aggregation mode
# Create static aggregation group 1.
[H3C] link-aggregation group 1 mode
static
# Add Ethernet1/0/1 through Ethernet1/0/3
to aggregation group 1.
[H3C] interface ethernet1/0/1
[H3C-Ethernet1/0/1] port
link-aggregation group 1
[H3C-Ethernet1/0/1] interface
ethernet0/2
[H3C-Ethernet1/0/2] port
link-aggregation group 1
[H3C-Ethernet1/0/2] interface
ethernet0/3
3)
Adopt the dynamic LACP aggregation mode
# Enable LACP on Ethernet1/0/1 through
Ethernet1/0/3.
<H3C> system-view
[H3C] interface Ethernet1/0/1
[H3C-Ethernet1/0/1] lacp enable
[H3C-Ethernet1/0/1] interface
Ethernet1/0/2
[H3C-Ethernet1/0/2] lacp enable
[H3C-Ethernet1/0/2] interface
Ethernet1/0/3
[H3C-Ethernet1/0/3] lacp enable
Note that the three LACP-enabled ports can
be aggregated into a dynamic aggregation group to implement load sharing only
when they have the same basic configuration, rate and duplex mode.
