When configuring link aggregation, go to
these sections for information you are interested in:
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Overview
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Link
Aggregation Classification
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Aggregation
Group Categories
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Link
Aggregation Configuration
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Displaying
and Maintaining Link Aggregation Configuration
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Link
Aggregation Configuration Example
Link aggregation can aggregate multiple Ethernet
ports together to form a logical aggregation group. To upper layer entities, all
the physical links in an aggregation group are a single logical link.
Link aggregation is designed to increase
bandwidth by implementing load sharing among the member ports in an aggregation
group. Link aggregation group also allows for port redundancy, which improves
connection reliability.
Link Aggregation Control Protocol (LACP) is
designed to implement dynamic link aggregation and deaggregation. This protocol
is based on IEEE802.3ad and uses link aggregation control protocol data units (LACPDUs)
to interact with its peer.
With LACP 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. In this way, the two parties can reach an agreement in
adding/removing the port to/from a dynamic aggregation group.
Operation key is generated by the system.
It is determined by port settings such as port speed, duplex mode, and basic
configurations (refer to Requirements
on Ports for Link Aggregation for description on basic
configurations).
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Selected ports in a manual aggregation group or
a static aggregation group have the same operation key.
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Member ports in a dynamic aggregation group have
the same operation key.
To achieve load sharing in an aggregation
group, the member ports to perform load balancing must have the same speed, duplex
mode, and basic configurations, which include:
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STP configuration, including STP status (enabled
or disabled), link attribute (point-to-point or not), STP priority, STP path
cost, STP packet format, loop guard status, root guard status, edge port or
not.
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QoS configuration, including traffic limit,
priority remarking, 802.1p priority, congestion avoidance, traffic redirection,
traffic statistics, and so on.
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VLAN configuration, including permitted VLANs,
and default VLAN ID.
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Link type configuration, which can be trunk, hybrid,
or access.
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GVRP configuration, including GVRP state
(enabled/disabled), GVRP registration type, and GARP timer settings.
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VLAN-VPN configuration, including VLAN-VPN state
(enabled/disabled), Set the TPID value for the port, Enable the inner-to-outer
tag priority replicating feature.
S5600 series
Ethernet switches support cross-device link aggregation if IRF fabric is
enabled.
Depending on different aggregation modes, the
following three types of link aggregation exist:
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Manual aggregation
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Static LACP aggregation
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Dynamic LACP aggregation
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 you cannot enable LACP on ports in a manual
aggregation group.
II. Port status in manual
aggregation group
A port in a manual aggregation group can be
in one of the two states: selected or unselected. In a manual aggregation
group, only the selected ports can forward user service packets.
In a manual aggregation group, the system
sets the ports to selected or unselected state according to the following rules.
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Among the ports in an aggregation group that are
in up state, the system determines the mater port with one of the following
settings being the highest (in descending order) as the master port: full
duplex/high speed, full duplex/low speed, half duplex/high speed, half
duplex/low speed. The ports with their rate, duplex mode and link type being
the same as that of the master port are selected ports, and the rest are unselected
ports.
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There is a limit on the number of selected ports
in an aggregation group. Therefore, if the number of the selected ports in an
aggregation group exceeds the maximum number supported by the device, those
with lower port numbers operate as the selected ports, and others as unselected
ports.
Among the selected ports in an aggregation
group, the one with smallest port number operates as the master port. Other
selected ports are the member ports.
III. Requirements on ports for
manual aggregation
Generally, there is no limit on the rate
and duplex mode of the ports (also including initially down port) you want to
add to a manual aggregation group.
1.2.2 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. When you remove a static aggregation group, all the member
ports in up state form one or multiple dynamic aggregations with LACP enabled.
LACP cannot be disabled on static aggregation ports.
II. Port status of static
aggregation group
A port in a static aggregation group can be
in one of the two states: selected or unselected.
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Both the selected and the unselected ports in
the up state can transceive LACP protocol packets.
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Only the selected ports can transceive service
packets; the unselected ports cannot.
In a static aggregation group, the system
sets the ports to selected or unselected state according to the following rules.
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Among the ports in an aggregation group that are
in up state, the system determines the master port with one of the following
settings being the highest (in descending order) as the master port: full
duplex/high speed, full duplex/low speed, half duplex/high speed, half
duplex/low speed. The ports with their rate, duplex mode and link type being
the same as that of the master port are selected port, and the rest are unselected
ports.
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The ports connected to a peer device different
from the one the master port is connected to or those connected to the same
peer device as the master port but to a peer port that is not in the same aggregation
group as the peer port of the master port are unselected ports.
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The system sets the ports with basic port configuration
different from that of the master port to unselected state.
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There is a limit on the number of selected ports
in an aggregation group. Therefore, if the number of the selected ports in an
aggregation group exceeds the maximum number supported by the device, those
with lower port numbers operate as the selected ports, and others as unselected
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 speed, duplex mode, and basic configurations,
and so are/do their peer ports.
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 and unselected.
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Both the selected and the unselected ports can receive/transmit
LACP protocol packets;
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The selected ports can receive/transmit user
service packets, but the unselected ports cannot.
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In a dynamic aggregation group, the selected
port with the smallest 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 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 unselected ports.
For an aggregation group:
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When the rate or duplex mode of a port in the
aggregation group changes, packet loss may occur on this port;
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When the rate of a port decreases, if the port
belongs to a manual or static LACP aggregation group, the port will be switched
to the unselected state; if the port belongs to a dynamic LACP aggregation
group, deaggregation will occur on the port.
1.3 Aggregation Group Categories
Depending on whether or not load sharing is
implemented, aggregation groups can be load-sharing or non-load-sharing
aggregation groups. When load sharing is implemented,
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For IP packets, the system will implement
load-sharing based on source IP address and destination IP address;
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For non-IP packets, the system will implement
load-sharing based on source MAC address and destination MAC address.
In general, the system only provides
limited load-sharing aggregation resources, 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.
Load-sharing aggregation resources are
allocated to aggregation groups in the following order:
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An aggregation group containing special ports
which require hardware aggregation resources has higher priority than any
aggregation group containing no special port.
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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).
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For aggregation groups, the one that might gain higher
speed if resources were allocated to it has higher priority than others. If the
groups can gain the same speed, the one with smallest master port number has
higher priority than other groups.
When an aggregation group of higher priority
appears, the aggregation groups of lower priorities release their hardware
resources. For single-port aggregation groups, they can transceive packets
normally without occupying aggregation resources
Caution:
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A load-sharing aggregation group contains at
least two selected ports, but a non-load-sharing aggregation group can only
have one selected port at most, while others are unselected ports.
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When more than eight load-sharing aggregation
groups are configured on a single switch, fabric ports cannot be enabled on
this switch.
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When no more than eight load-sharing aggregation
groups are configured on a single switch, fabric ports can be enabled on this
switch. The aggregation groups added subsequently are all non-load-sharing
aggregation groups. If the fabric ports are disabled, the state of these
non-load-sharing aggregation groups will not be changed automatically. These
non-load-sharing aggregation groups will become load-sharing aggregation groups
only after the unselected ports in these aggregation groups are unplugged and
then plugged or the shutdown command and then the undo shutdown
command are executed.
Caution:
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The commands of link aggregation cannot be
configured with the commands of port loopback detection feature at the same
time.
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The ports where the mac-address max-mac-count
command is configured cannot be added to an aggregation group. Contrarily, the mac-address
max-mac-count command cannot be configured on a port that has already been
added to an aggregation group.
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MAC-authentication-enabled ports and
802.1x-enabled ports cannot be added to an aggregation group.
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Mirroring destination ports and mirroring
reflector ports cannot be added to an aggregation group.
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Ports configured with blackhole MAC addresses,
static MAC addresses, multicast MAC addresses, or the static ARP protocol cannot
be added to an aggregation group.
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Ports where the IP-MAC address binding is
configured cannot be added to an aggregation group.
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Port-security-enabled ports cannot be added to an
aggregation group.
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The port with Voice VLAN enabled cannot be added
to an aggregation group.
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Do not add ports with the inter-VLAN MAC address
replicating function of the selective QinQ feature enabled to an aggregation
group.
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Do not add ports with IP filtering enabled to an
aggregation group.
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Do not add ports with ARP intrusion detection enabled
to an aggregation group.
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Do not add ports with source IP addresses/source
MAC addresses statically bound to them to an aggregation group.
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Web-authentication-enabled ports 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 will be removed from the group).
For a manual aggregation group, a port can
only be manually added/removed to/from the manual aggregation group.
Follow these steps to configure a manual aggregation group:
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To do…
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Use the command…
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Remarks
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Enter
system view
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system-view
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—
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Create a
manual aggregation group
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link-aggregation
group agg-id mode manual
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Required
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Enter
Ethernet port view
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interface interface-type interface-number
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—
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Add the Ethernet
port to the aggregation group
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port
link-aggregation group agg-id
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Required
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Note that:
1)
When creating an aggregation group:
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If the aggregation group you are creating
already exists but contains no port, its type will change to the type you set.
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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.
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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 group to a static 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 LACP aggregation group (after that, the
system will re-aggregate the original member ports in the group to form one or multiple
dynamic aggregation groups.).
For a static aggregation group, a port can
only be manually added/removed to/from the static aggregation group.
When you add an
LACP-enabled port to a manual aggregation group, the system will automatically
disable LACP on the port. Similarly, when you add an LACP-disabled port to a
static aggregation group, the system will automatically enable LACP on the
port.
Follow these steps
to configure a static LACP aggregation group:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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Create a static aggregation group
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link-aggregation group agg-id mode static
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Required
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Enter Ethernet port view
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interface interface-type interface-number
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—
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Add the port to the aggregation group
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port link-aggregation group agg-id
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Required
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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.
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 which
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.
You cannot enable
LACP on a port which is already in a manual aggregation group.
Follow these steps
to configure a dynamic LACP aggregation group:
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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Configure the system priority
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lacp system-priority
system-priority
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Optional
By default, the system priority is
32,768.
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Enter Ethernet port view
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interface interface-type interface-number
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—
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Enable LACP on the port
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lacp enable
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Required
By default, LACP is disabled on a port.
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Configure the port priority
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lacp port-priority
port-priority
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Optional
By default, the port priority is 32,768.
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Changing the system
priority may affect the priority relationship between the aggregation peers,
and thus affect the selected/unselected status of member ports in the dynamic
aggregation group.
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To do…
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Use the command…
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Remarks
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Enter system view
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system-view
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—
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Configure a description for an
aggregation group
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link-aggregation group agg-id description agg-name
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Optional
By default, no description is configured for
an aggregation group.
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Caution:
If you have saved
the current configuration with the save command, after system reboot,
the configuration concerning manual and static aggregation groups and their
descriptions still exists, but that of dynamic aggregation groups and their
descriptions gets lost.
1.5 Displaying and Maintaining Link Aggregation Configuration
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To do…
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Use the command…
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Remarks
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Display summary information of all
aggregation groups
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display link-aggregation summary
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Available in any view
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Display detailed information of a
specific aggregation group or all aggregation groups
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display link-aggregation verbose [ agg-id ]
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Display link aggregation details of a
specified port or port range
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display link-aggregation interface interface-type interface-number [ to
interface-type interface-number ]
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Display local device ID
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display lacp system-id
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Clear LACP statistics about a specified
port or port range
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reset lacp statistics [ interface interface-type interface-number [ to
interface-type interface-number ] ]
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Available in user view
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I. Network requirements
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Switch A connects to Switch B with three ports GigabitEthernet
1/0/1 to GigabitEthernet 1/0/3. It is required that load between the two switches
can be shared among the three ports.
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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)
Adopting manual aggregation mode
# Create manual aggregation group 1.
<Sysname> system-view
[Sysname] link-aggregation group 1
mode manual
# Add GigabitEthernet 1/0/1 through GigabitEthernet
1/0/3 to aggregation group 1.
[Sysname] interface GigabitEthernet1/0/1
[Sysname-GigabitEthernet1/0/1] port
link-aggregation group 1
[Sysname-GigabitEthernet1/0/1] quit
[Sysname] interface GigabitEthernet 1/0/2
[Sysname-GigabitEthernet1/0/2] port
link-aggregation group 1
[Sysname-GigabitEthernet1/0/2] quit
[Sysname] interface GigabitEthernet1/0/3
[Sysname-GigabitEthernet1/0/3] port
link-aggregation group 1
2)
Adopting static LACP aggregation mode
# Create static aggregation group 1.
<Sysname> system-view
[Sysname] link-aggregation group 1
mode static
# Add GigabitEthernet 1/0/1 through GigabitEthernet
1/0/3 to aggregation group 1.
[Sysname] interface GigabitEthernet 1/0/1
[Sysname-GigabitEthernet1/0/1] port
link-aggregation group 1
[Sysname-GigabitEthernet1/0/1] quit
[Sysname] interface GigabitEthernet 1/0/2
[Sysname-GigabitEthernet1/0/2] port
link-aggregation group 1
[Sysname-GigabitEthernet1/0/2] quit
[Sysname] interface GigabitEthernet1/0/3
[Sysname-GigabitEthernet1/0/3] port
link-aggregation group 1
3)
Adopting dynamic LACP aggregation mode
# Enable LACP on GigabitEthernet 1/0/1
through GigabitEthernet 1/0/3.
<Sysname> system-view
[Sysname] interface GigabitEthernet 1/0/1
[Sysname-GigabitEthernet1/0/1] lacp
enable
[Sysname-GigabitEthernet1/0/1] quit
[Sysname] interface GigabitEthernet 1/0/2
[Sysname-GigabitEthernet1/0/2] lacp
enable
[Sysname-GigabitEthernet1/0/2] quit
[Sysname] interface GigabitEthernet1/0/3
[Sysname-GigabitEthernet1/0/3] lacp
enable
Caution:
The three
LACP-enabled ports can be aggregated into one dynamic aggregation group to
implement load sharing only when they have the same basic configuration (such
as rate, duplex mode, and so on).
