A port channel is an aggregation of multiple physical interfaces that creates a logical interface. You can bundle up to eight individual active links into a port channel to provide increased bandwidth and redundancy. Port channeling also load balances traffic across these physical interfaces. The port channel stays operational as long as at least one physical interface within the port channel is operational.
You can use static port channels, with no associated aggregation protocol, for a simplified configuration.
Port Channels
A port channel bundles physical links into a channel group to create a single logical link that provides the aggregate bandwidth of up to eight physical links. If a member port within a port channel fails, the traffic previously carried over the failed link switches to the remaining member ports within the port channel.
You can bundle up to eight ports into a static port channel without using any aggregation protocol.
Note
The device does not support Port Aggregation Protocol (PAgP) for port channels.
Each port can be in only one port channel. All the ports in a port channel must be compatible; they must use the same speed and duplex mode. When you run static port channels with no aggregation protocol, the physical links are all in the on channel mode.
You can create port channels directly by creating the port channel interface, or you can create a channel group that acts to aggregate individual ports into a bundle. When you associate an interface with a channel group, the software creates a matching port channel automatically if the port channel does not already exist. In this instance, the port channel assumes the Layer 2 configuration of the first interface. You can also create the port channel first. In this instance, the Cisco Nexus 1000V creates an empty channel group with the same channel number as the port channel and takes the default Layer 2 configuration, as well as the compatibility configuration.
Note
The port channel is operationally up when at least one of the member ports is up and is in the channeling state. The port channel is operationally down when all member ports are operationally down.
Compatibility Checks
When you add an interface to a port channel group, the following compatibility checks are made before allowing the interface to participate in the port channel:
Network layer
(Link) speed capability
Speed configuration
Duplex capability
Duplex configuration
Port mode
Access VLAN
Trunk native VLAN
Tagged or untagged
Allowed VLAN list
MTU size
SPAN—cannot be a SPAN source or a destination port
Storm control
To view the full list of compatibility checks performed by the Cisco Nexus 1000V, use the show port-channel compatibility-parameters.
You can only add interfaces configured with the channel mode set to on to static port channels. You can configure these attributes on an individual member port. If you configure a member port with an incompatible attribute, the Cisco Nexus 1000V suspends that port in the port channel.
Alternatively, you can force ports with incompatible parameters to join the port channel if the following parameters are the same:
(Link) speed capability
Speed configuration
Duplex capability
Duplex configuration
When the interface joins a port channel, some of its individual parameters are removed and replaced with the values on the port channel as follows:
Bandwidth
Delay
Extended Authentication Protocol over UDP
VRF
IP address (v4 and v6)
MAC address
Spanning Tree Protocol
NAC
Service policy
Quality of Service (QoS)
Access control lists (ACLs)
The following interface parameters remain unaffected when the interface joins or leaves a port channel:
Description
CDP
MDIX
Rate mode
Shutdown
SNMP trap
Note
When you delete the port channel, the software sets all member interfaces as if they were removed from the port channel.
Load Balancing Using Port Channels
The Cisco Nexus 1000V load balances traffic across all operational interfaces in a port channel by hashing the addresses in the frame to a numerical value that selects one of the links in the channel. Port channels provide load balancing by default. Port channel load balancing uses MAC addresses, IP addresses, or Layer 4 port numbers to select the link. Port channel load balancing uses either source or destination addresses or ports, or both source and destination addresses or ports.
You can configure the load balancing mode to apply to all port channels that are configured on the entire device or on specified modules. The per-module configuration takes precedence over the load-balancing configuration for the entire device. You can configure one load balancing mode for the entire device, a different mode for specified modules, and another mode for the other specified modules. You cannot configure the load balancing method per port channel.
You can configure the type of load balancing algorithm used. You can choose the load balancing algorithm that determines which member port to select for egress traffic by looking at the fields in the frame.
Note
The default load balancing method uses source MAC addresses.
You can configure one of the following methods to load balance across the port channel:
Destination MAC address
Source MAC address
Source and destination MAC addresses
Destination IP address and VLAN
Source IP address and VLAN
Source and destination IP address and VLAN
Destination TCP/UDP port number
Source TCP/UDP port number
Source and destination TCP/UDP port number
Destination IP address and TCP/UDP port number
Source IP address and TCP/UDP port number
Source and destination IP address and TCP/UDP port number
Destination IP address, TCP/UDP port number, and VLAN
Source IP address, TCP/UDP port number, and VLAN
Source and destination IP address, TCP/UDP port number, and VLAN
Destination IP address
Source IP address
Source and destination IP addresses
VLAN only
Source virtual port ID
When you configure source IP address load balancing, the source MAC address is used to balance the traffic load. When you configure the destination MAC address load balancing method, the traffic load is balanced using the destination MAC address.
When you configure source IP address load balancing, the source MAC address is used to balance the traffic load. When you configure the destination MAC address load balancing method, the traffic load is balanced using the destination MAC address.
The load balancing methods that use port channels do not apply to multicast traffic. Regardless of the method configured, multicast traffic uses the following methods for load balancing with port channels:
Multicast traffic with Layer 4 information—Source IP address, source port, destination IP address, and destination port
Multicast traffic without Layer 4 information—Source IP address and destination IP address
Non-IP multicast traffic—Source MAC address and destination MAC address
The Link Aggregation Control Protocol (LACP) allows you to configure up to 16 interfaces into a port channel. A maximum of eight interfaces can be active, and a maximum of eight interfaces can be placed in a standby state. The following figure shows how individual links can be combined into LACP port channels and channel groups as well as function as individual links.
Note
When you delete the port channel, the associated channel group is automatically deleted. All member interfaces revert to their original configuration.
LACP port channels on Cisco virtual interface cards do not support more than two VNICs.
Figure 1. Individual Links Combined into a Port Channel
You can offload operation of the LACP from the Virtual Supervisor Module (VSM) to the Virtual Ethernet Ports (VEMs). To prevent a situation where the VSM cannot negotiate LACP with the upstream switch when the VEM is disconnected from the VSM (referred to as headless mode). VEM management of LACP allows it to reestablish port channels after the reboot of a headless VEM.
Port Channel Modes
Individual interfaces in port channels are configured with channel modes. When you run static port channels with no aggregation protocol, the channel mode is always set to on.
You enable LACP for each channel by setting the channel mode for each interface to active or passive. You can configure either channel mode for individual links in the LACP channel group when you are adding the links to the channel group.
The following table describes the channel modes.
Table 1 Channel Modes for Individual Links in a Port Channel
Channel Mode
Description
passive
LACP mode that places a port into a passive negotiating state in which the port responds to LACP packets that it receives but does not initiate LACP negotiation.
active
LACP mode that places a port into an active negotiating state in which the port initiates negotiations with other ports by sending LACP packets.
on
All static port channels (that are not running LACP) remain in this mode. If you attempt to change the channel mode to active or passive before enabling LACP, the device displays an error message.
You enable LACP on each channel by configuring the interface in that channel for the channel mode as either active or passive. When an LACP attempts to negotiate with an interface in the on state, it does not receive any LACP packets and becomes an individual link with that interface; it does not join the LACP channel group.
The default port channel mode is on.
Both the passive and active modes allow LACP to negotiate between ports to determine if they can form a port channel based on criteria such as the port speed and the trunking state. The passive mode is useful when you do not know whether the remote system, or partner, supports LACP.
Ports can form an LACP port channel when they are in different LACP modes if the modes are compatible as in these examples:
A port in active mode can form a port channel successfully with another port that is in active mode.
A port in active mode can form a port channel with another port in passive mode.
A port in passive mode cannot form a port channel with another port that is also in passive mode, because neither port will initiate negotiation.
A port in on mode is not running LACP and cannot form a port channel with another port that is in active or passive mode.
LACP ID Parameters
This section describes the LACP parameters.
LACP System Priority
Each system that runs LACP has an LACP system priority value. You can accept the default value of 32768 for this parameter, or you can configure a value between 1 and 65535. LACP uses the system priority with the MAC address to form the system ID and also uses the system priority during negotiation with other devices. A higher system priority value means a lower priority.
Note
The LACP system ID is the combination of the LACP system priority value and the MAC address.
LACP Port Priority
Each port that is configured to use LACP has an LACP port priority. You can accept the default value of 32768 for the LACP port priority, or you can configure a value between 1 and 65535. LACP uses the port priority with the port number to form the port identifier.
LACP uses the port priority to decide which ports should be put in standby mode when there is a limitation that prevents all compatible ports from aggregating and which ports should be put into active mode. A higher port priority value means a lower priority for LACP. You can configure the port priority so that specified ports have a lower priority for LACP and are most likely to be chosen as active links, rather than as hot-standby links.
LACP Administrative Key
LACP automatically configures an administrative key value that is equal to the channel-group number on each port configured to use LACP. The administrative key defines the ability of a port to aggregate with other ports. A port’s ability to aggregate with other ports is determined by these factors:
Port physical characteristics, such as the data rate and the duplex capability
Configuration restrictions that you establish
LACP Marker Responders
You can dynamically redistribute the data traffic by using port channels. This redistribution may result from a removed or added link or a change in the load-balancing scheme. Traffic redistribution that occurs in the middle of a traffic flow can cause misordered frames.
LACP uses the Marker Protocol to ensure that frames are not duplicated or reordered due to this redistribution. The Marker Protocol detects when all the frames of a given traffic flow are successfully received at the remote end. LACP sends Marker PDUs on each of the port-channel links. The remote system responds to the Marker PDU once it receives all the frames received on this link prior to the Marker PDU. The remote system then sends a Marker Responder. Once the Marker Responders are received by the local system on all member links of the port channel, the local system can redistribute the frames in the traffic flow with no chance of misordering. The software supports only Marker Responders.
LACP-Enabled and Static Port Channels Differences
The following table summarizes the major differences between port channels with LACP enabled and static port channels.
Table 2 Port Channels with LACP Enabled and Static Port Channels
Configurations
Port Channels with LACP Enabled
Static Port Channels
Protocol applied
Enable globally
Not applicable
Channel mode of links
Can be either:
Active
Passive
Can only be On
Maximum number of links in channel
16
8
vPC Host Mode
You use vPC-HM mode to create a port channel when the switch is connected to multiple upstream switches that are not clustered. In the Cisco Nexus 1000V, the port channel is divided into subgroups or logical smaller port channels, each representing one or more uplinks to one upstream physical switch.
Links that connect to the same physical switch are bundled in the same subgroup automatically by using information gathered from the Cisco Discovery Protocol (CDP) packets from the upstream switch. Interfaces can also be manually assigned a specific subgroup.
You use vPC-HM, each vEthernet interface on the VEM is mapped to one of two subgroups in a round-robin method. All traffic from the vEthernet interface uses the assigned subgroup unless it is unavailable, in which case the vEthernet interface fails over to the remaining subgroup. When the original subgroup becomes available again, traffic shifts back to it. Traffic from each vEthernet interface is then balanced based on the configured hashing algorithm.
When multiple uplinks are attached to the same subgroup, you must configure the upstream switch in a port channel with the links bundled together. The port channel must also be configured with the channel-group auto mode on (active and passive modes use LACP).
If the upstream switches do not support port channels, you can use MAC pinning to assign each Ethernet port member to a particular port channel subgroup.
Note
Do not configure vPC-HM on the Cisco Nexus 1000V when the upstream switch ports that connect to the VEMs have vPC configured. If vPC is configured, the connection can be interrupted or disabled.
The following figure shows how to use vPC-HM to assign member ports 1 and 2 to subgroup ID 0 and member ports 3 and 4 to subgroup ID 1.
Figure 2. Using vPC-HM to Connect a Port Channel to Multiple Upstream Switches
Subgroup Creation
If Cisco Discovery Protocol (CDP) is enabled on the upstream switches, then subgroups are automatically created using information gathered from the CDP packets. If not, you must manually create subgroups.
Static Pinning
Static pinning allows you to pin the virtual ports behind a VEM to a particular subgroup within the channel. Instead of allowing round robin dynamic assignment between the subgroups, you can assign (or pin) a static vEthernet interface, control VLAN, or packet VLAN to a specific port channel subgroup. With static pinning, traffic is forwarded only through the member ports in the specified subgroup.
You can also pin vEthernet interfaces to subgroups in interface configuration mode.
MAC Pinning
If you are connecting to multiple upstream switches that do not support port channels, then MAC pinning is the preferred configuration. MAC pinning divides the uplinks from your server into standalone links and pins the MAC addresses to those links in a round-robin method. This ensures that the MAC address of a virtual machine is never seen on multiple upstream switch interfaces. Therefore no upstream configuration is required to connect the VEM to upstream switches.
MAC pinning does not rely on any protocol to distinguish upstream switches so the configuration is independent of upstream hardware or design.
In case of a failure, the Cisco Nexus 1000V first sends a gratuitous ARP packet to the upstream switch indicating that the VEM MAC address will now be learned on a different link. It also allows for sub-second failover time.
The following figure shows each member port that is assigned to a specific port channel subgroup using MAC pinning.
Figure 3. Using MAC Pinning to Connect a Port Channel to Multiple Upstream Switches
MAC Pinning Relative
This feature modifies the existing algorithm for MAC pinning where the port-channel uses the port number (vmnic number) as the subgroup ID for an Ethernet member port.
The new algorithm assigns zero-based logical subgroup IDs to Ethernet member ports. The member port that has the lowest port number (vmnic number) is assigned subgroup ID 0.
The following figure shows each member port that is assigned to a specific port channel subgroup using MAC pinning relative.
Figure 4. Using MAC Pinning Relative to Connect a Port Channel to Multiple Upstream Switches
Network State Tracking for vPC-HM
Network state tracking for vPC-HM identifies link failures where other detection methods fail, and verifies Layer 2 connectivity between vPC-HM channel subgroups. It is not intended to detect network configuration problems.
Network state tracking selects one uplink interface in each sub group for broadcasting packets to a tracking VLAN. The tracking VLAN is usually the lowest forwarding VLAN for trunk ports and the primary VLAN for promiscuous access ports. The packets that are received back from the network on each subgroup are tracked as are the number of consecutively missed broadcasts. If the missed broadcasts for a sub group exceed the threshold, the port channel is considered to be in split mode. In split mode, the interfaces are marked as inactive, and traffic is pinned to active interfaces.
System messages indicate when a port channel enters or recovers from split mode; and interfaces are marked active or inactive.
High Availability
Port channels provide high availability by load balancing traffic across multiple ports. If a physical port fails, the port channel is still operational if there is an active member in the port channel.
Port channels support stateful and stateless restarts. A stateful restart occurs on a supervisor switchover. After the switchover, the Cisco Nexus 1000V applies the runtime configuration after the switchover.
Prerequisites for Port Channels
Port channeling has the following prerequisites:
You are logged into the Cisco Nexus 1000V in EXEC mode.
All ports for a single port channel must meet the compatibility requirements. See Compatibility Checks for more information about the compatibility requirements.
You can use virtual vPC-HM to configure a port channel even when the physical ports are connected to two different switches.
Guidelines and Limitations
Port channeling has the following guidelines and restrictions:
All ports in the port channel must be in the same Cisco Nexus 1000V module; you cannot configure port channels across Cisco Nexus 1000V modules.
Port channels can be formed with multiple upstream links only when they satisfy the compatibility requirements and under the following conditions:
The uplinks from the host are going to the same upstream switch.
The uplinks from the host going to multiple upstream switches are configured with vPC-HM.
You can configure multiple port channels on a device.
After you configure a port channel, the configuration that you apply to the port channel interface affects the port channel member ports. The configuration that you apply to the member ports affects only the member port where you apply the configuration.
You must remove the port security information from a port before you can add that port to a port channel. You cannot apply the port security configuration to a port that is a member of a channel group.
You can configure ports that belong to a port channel group as PVLAN ports.
Any configuration changes that you apply to the port channel is applied to every member interface of that port channel.
Channel member ports cannot be source or destination SPAN ports.
To support LACP when inband/AIPC are also carried over the link, you must configure the following commands on the ports connected to the ESX host:
spanning-tree portfast trunk
spanning-tree bpdufilter enable
Note
If you have a separate dedicated NIC for control traffic, these settings are not required.
There should be at least two links that connect two switches when inband/AIPC are also carried over the LACP channel.
If you configure LACP and your upstream switch uses the LACP suspend feature, make sure this feature is disabled. For more information, see the documentation for your upstream switch.
If you are connecting to an upstream switch or switches that do not support port channels, MAC pinning is the preferred configuration. MAC pinning divides the uplinks from your server into standalone links and pins the MAC addresses to those links in a round-robin method. The drawback is that you cannot leverage the load sharing performance that LACP provides.
Once a port profile is created, you cannot change its type (Ethernet or vEthernet).
The server administrator should not assign more than one uplink on the same VLAN without port channels. It is not supported to assign more than one uplink on the same host to a profile without port channels or port profiles that share one or more VLANs.
Caution
Disruption of connectivity might result if you configure vPC-HM on the Cisco Nexus 1000V when vPC is also configured on the ports of upstream switches that connect to its VEMs.
You must have already configured the Cisco Nexus 1000Vsoftware using the setup routine. For information, see the Cisco Nexus 1000V Installation and Upgrade Guide.
The Cisco Nexus 1000V must be connected to the SCVMM.
You are logged in to the CLI in EXEC mode.
When you create a port channel, an associated channel group is automatically created.
If Link Aggregation Control Protocol (LACP) support is required for the port channel, you must enable the LACP feature before you can configure it.
Network State Tracking is only supported with HP Virtual Connect where one physical link from the Flex-10 fabric appears as four Flex-10 NICs (physical NICs) to the VMkernel.
Default Settings
Table 3 Default Settings for Port Channels
Parameters
Default
Port profile type
vEthernet
Port profile administrative state
All ports are disabled.
Port channel
Admin up
LACP
Disabled
Note
If upgrading to Release 4.2(1)SV1(5.2) from a previous release, LACP offload is disabled by default.
Load balancing method for Layer 2 interfaces
Source and destination MAC address
Load balancing per module
Disabled
Channel mode
on
LACP offload
(Offloading LACP management to VEMs)
Enabled
Note
If upgrading to Release 4.2(1)SV1(5.2) from a previous release, LACP offload is disabled by default.
Network State Tracking: Broadcast interval
5 seconds
Network State Tracking: Split-network mode action
repin
Network State Tracking: Maximum threshold miss count
5 seconds
Network State Tracking: State
Disabled
Configuring Port Channels
Creating a Port Profile for a Port Channel
You can define a port channel in a port profile and, if needed, to configure and pin interface or VLAN subgroups.
You can configure a port channel whose ports are connected to the same upstream switch. If the ports are connected to multiple upstream switches, see Connecting to Multiple Upstream Switches
.
Before You Begin
The channel group number assignment is made automatically when the port profile is assigned to the first interface.
Procedure
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
switch(config)# port-profile [ type {ethernet | vethernet}] name
Enters port profile configuration mode for the named port profile.
name—Specifies the port profile name, which can be up to 80 characters and must be unique for each port profile on the Cisco Nexus 1000V.
type—Specifies the port profile as an Ethernet or vEthernet type. Once configured, this setting cannot be changed. The default is the vEthernet type.
For configuring port channels, specify the port profile as an Ethernet type.
Defining a port profile as an Ethernet type allows the port profile to be used for physical (Ethernet) ports. In the vCenter Server, the corresponding port group can be selected and assigned to physical ports (PNICs).
Note
If a port profile is configured as an Ethernet type, it cannot be used to configure VMware virtual ports.
Step 3
switch(config-port-prof)# channel-group auto [mode {on | active | passive}] [ mac-pinning [relative]]
Defines a port channel group in which a unique port channel is created and automatically assigned when the port profile is assigned to the first interface.
Each additional interface that belongs to the same module is added to the same port channel. In VMware environments, a different port channel is created for each module.
mode—Sets the port channel mode to on, active, or passive (active and passive use LACP).
mac-pinning—Designates that one subgroup per Ethernet member port must be automatically assigned if the upstream switch does not support port channels.
relative—Specifies that the subgroup numbering begins at zero and continues numbering the subgroups consecutively.
Step 4
switch(config-port-prof)# show port-profile [brief | expand-interface | usage] [nameprofile-name]
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to configure a port channel that connects to one upstream switch:
switch# configure terminal
switch(config)# port-profile AccessProf
switch(config-port-prof)# channel-group auto mode on
switch(config-port-prof)# show port-profile name AccessProf
port-profile AccessProf
description: allaccess4
status: disabled
capability l3control: no
pinning control-vlan: -
pinning packet-vlan: -
system vlans: none
port-group:
max ports: 32
inherit:
config attributes:
channel-group auto mode on
evaluated config attributes:
channel-group auto mode on
assigned interfaces:
switch(config-port-prof)#
Connecting to Multiple Upstream Switches
You can create a port channel that connects to multiple upstream switches.
Configure an uplink port profile to be used by the physical NICs in the VEM in virtual port channel-host mode (vPC-HM) when the ports connect to multiple upstream switches.
If you are connecting to multiple upstream switches that do not support port channels, then MAC pinning is the preferred configuration. You can configure MAC pinning using this procedure.
The channel group mode must be set to on (active and passive modes use LACP).
You must know whether CDP is configured in the upstream switches.
If configured, CDP packets from the upstream switch are used to automatically create a subgroup for each upstream switch to manage its traffic separately.
If not configured, after completing this procedure, you must manually configure subgroups to manage the traffic flow on the separate switches. See Manually Configuring Interface Subgroups.
Caution
Connectivity may be disrupted for up to 60 seconds if the CDP timer is set to 60 seconds (the default).
Caution
The VMs behind the Cisco Nexus 1000V receive duplicate packets from the network for unknown unicasts, multicast floods, and broadcasts if vPC-HM is not configured when port channels connect to two different upstream switches.
Procedure
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
switch(config)# port-profile [type {ethernet | vethernet}] name
Enters port profile configuration mode for the named port profile.
name—Specifies the port profile name, which can be up to 80 characters and must be unique for each port profile on the Cisco Nexus 1000V.
type—Specifies the port profile as an Ethernet or vEthernet type. Once configured, this setting cannot be changed. The default is the vEthernet type.
For configuring port channels, specify the port profile as an Ethernet type.
Defining a port profile as an Ethernet type allows the port profile to be used for physical (Ethernet) ports. In the vCenter Server, the corresponding port group can be selected and assigned to physical ports (PNICs).
Note
If a port profile is configured as an Ethernet type, it cannot be used to configure VMware virtual ports.
Step 3
switch(config-port-prof)# channel-group auto mode on [sub-group {cdp | manual }] [mac-pinning [ relative]]
Creates a unique asymmetric port channel (also known as vPC-HM) and automatically assigns it when the port profile is assigned to the first interface.
Each additional interface that belongs to the same module is added to the same port channel. In VMware environments, a different port channel is created for each module.
The following options are also defined:
mode—Sets the port channel mode to on (active and passive use LACP)
sub-group—Identifies this channel group as asymmetric, or connected to more than one switch.
cdp—Specifies that CDP information is used to automatically create subgroups for managing the traffic flow.
manual: Specifies that subgroups are configured manually. This option is used if CDP is not configured on the upstream switches. To configure subgroups, see Manually Configuring Interface Subgroups.
mac-pinning—Specifies that Ethernet member ports are assigned to subgroups automatically, one subgroup per member port. This option is used if the upstream switch does not support port channels.
relative—The subgroup numbering begins at zero and continues numbering the subgroups consecutively.
Step 4
switch(config-port-prof)# show port-profile [ brief | expand-interface | usage] [nameprofile-name]
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to create a port channel that connects to multiple upstream switches that support CDP:
switch# configure terminal
switch(config)# port-profile UpLinkProfile2
switch(config-port-prof)# channel-group auto mode on sub-group cdp
switch(config-port-prof)# show port-profile name UpLinkProfile2
port-profile UpLinkProfile2
description:
type: ethernet
status: disabled
capability l3control: no
pinning control-vlan: -
pinning packet-vlan: -
system vlans: none
port-group:
max ports: 32
inherit:
config attributes:
channel-group auto mode on sub-group cdp
evaluated config attributes:
channel-group auto mode on sub-group cdp
assigned interfaces:
switch(config-port-prof)# copy running-config startup-config
This example shows how to create a port channel that connects to multiple upstream switches that do not support CDP:
switch# configure terminal
switch(config)# port-profile UpLinkProfile3
switch(config-port-prof)# exit
switch(config)# interface ethernet3/2-3
switch(config-if)# sub-group-id 0
switch(config-port-prof)# show port-profile name
switch(config-port-prof)# show port-profile name UplinkProfile3
port-profile UplinkProfile3
description:
type: ethernet
status: enabled
capability l3control: no
pinning control-vlan: -
pinning packet-vlan: -
system vlans: none
port-group: UplinkProfile3
max ports: -
inherit:
config attributes:
channel-group auto mode on sub-group manual
evaluated config attributes:
channel-group auto mode on sub-group manual
assigned interfaces:
switch(config-port-prof)# copy running-config startup-config
This example shows how to create a port channel that connects to multiple upstream switches that do not support port channels:
switch# configure terminal
switch(config)# port-profile UpLinkProfile1
switch(config-port-prof)# channel-group auto mode on mac-pinning
switch(config-port-prof)# show port-profile name UpLinkProfile1
port-profile UpLinkProfile1
description:
type: ethernet
status: disabled
capability l3control: no
pinning control-vlan: -
pinning packet-vlan: -
system vlans: none
port-group:
max ports: 32
inherit:
config attributes:
channel-group auto mode on mac-pinning
evaluated config attributes:
channel-group auto mode on mac-pinning
assigned interfaces:
switch(config-port-prof)# copy running-config startup-config
Manually Configuring Interface Subgroups
You can manually configure port channel subgroups to manage the traffic flow on multiple upstream switches. This action is required for a port channel that connects to multiple upstream switches where CDP is not configured.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to manually configure port channel subgroups for a host in module 3 which has four physical ports. The upstream switches do not support CDP. Ethernet ports 3/2 and 3/3 connect to one upstream switch and the Ethernet ports 3/4 and 3/5 connect to another upstream switch.
You can migrate a channel group to a port profile.
Before You Begin
Log in to the CLI in EXEC mode.
Procedure
Step 1
Place the host in maintenance mode.
Step 2
Do one of the following:
If distributed resource scheduling (DRS) is enabled, make sure to wait until the virtual machines are migrated to other host(s).
Otherwise, manually migrate the virtual machines.
Step 3
When all the virtual machines are successfully migrated, from the Cisco Nexus 1000V CLI, create a new Ethernet type port profile for the uplink ports on this host.
Enter one of the following commands:
channel-group auto mode active | passive
channel-group auto mode on mac-pinning
Perform a CLI override on the existing port channels.
Step 4
Remove the port channel configuration from the uplink switches.
Note
The new port channel has a new port channel ID.
Step 5
When all the port(s) are moved from the old port profile, use the following command from the Cisco Nexus 1000V CLI to delete the port channels with zero members:no interface port-channelid
Step 6
Bring the host out of maintenance mode.
Step 7
To save the running configuration persistently through reboots and restarts by copying it to the startup configuration, enter the following command:
To move port profile types in a port profile, you tear down the existing port channel then recreate the port channel.
Before You Begin
Log in to the CLI in EXEC mode.
Procedure
Step 1
Place the host in maintenance mode.
Step 2
Do one of the following:
If distributed resource scheduling (DRS) is enabled, make sure to wait until the virtual machines are migrated to other host(s).
Otherwise, manually migrate the virtual machines.
Step 3
When all the virtual machines are successfully migrated, from the Cisco Nexus 1000V CLI, create a new Ethernet type port profile for the uplink ports on this host.
Enter one of the following commands:
channel-group auto mode active | passive
channel-group auto mode on mac-pinning
Perform a CLI override on the existing port channels.
To save the running configuration persistently through reboots and restarts by copying it to the startup configuration by entering the following command:
You can configure Network State Tracking to pinpoint link failures on port channels configured for vPC-HM.
Before You Begin
Log in to the CLI in EXEC mode.
Once enabled, Network State Tracking is used on every VEM that is configured with a vPC-HM port profile.
If you specify repinning (the default) and a split network is detected, know that Ethernet interfaces are inactivated, and the vEths are redistributed among all interfaces including the reactivated Ethernet interfaces. Restoration to the earlier pinned state is not guaranteed.
Procedure
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
switch(config)# track network-state enable
Enables Network State Tracking on all interfaces in vPC-HM port-channels.
Specifies the interval of time, from 1 to 10 seconds, between which tracking broadcasts are sent; and the interval for tracking packets. The default interval is 5 seconds between broadcasts.
Specifies the maximum number of broadcasts that can be missed successively (from 3 to 7) before a split network is declared. The default is 5 missed broadcasts.
Step 6
switch(config)# show network-state tracking config
(Optional)
Displays the Network State Tracking configuration for verification.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to configure Network State Tracking with an 8 second interval between each sent broadcast, repinning traffic to another uplink if a split network is detected, and a maximum of 7 missed broadcasts before declaring a split network:
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to remove a port channel group from a port profile:
switch# configure terminal
switch(config)# port-profile testProf
switch(config-port-prof)# no channel-group auto
switch(config-port-prof)# show port-profile testProf
switch(config-port-prof)#
Shutting Down and Restarting a Port Channel Interface
You can shut down and restart a port channel interface.
Before You Begin
Log in to the CLI in EXEC mode.
When you shut down a port channel interface, know that no traffic passes, and the interface is administratively down.
Enters interface configuration mode for the specified port channel interface.
Step 3
switch(config-if)# shutdown | no shutdown
The shutdownkeyword shuts down the interface. No traffic passes and the interface displays as administratively down. The default is no shutdown.
Brings the interface back up. The interface displays as administratively up. If there are no operational problems, traffic passes. The default is no shutdown.
Step 4
switch(config-if)# show interface port-channelchannel-number
(Optional)
Displays interface information for the specified port channel.
Places you into interface configuration mode for the specified port channel interface.
For the channel number, the range is from 1 to 4096. The port channel associated with this channel group is automatically created if the port channel does not already exist.
Step 3
switch(config-if)# descriptionstring
Adds a description to the port channel interface.
For string, the description can be up to 80 alphanumeric characters.
Note
You do not need to use quotations around descriptions that include spaces.
Step 4
switch(config-if)# show interface port-channelchannel-number
(Optional)
Displays interface information for the specified port channel.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to restore the default load-balancing method:
switch# configure terminal
switch(config)# no port-channel load-balance ethernet
switch(config)# show port-channel load-balance
Configuring an LACP Port Channel
You can configure the following requirements for LACP:
Enable LACP support for port channels.
Configure the individual port channel links so that they are allowed to operate with LACP.
Configure a system uplink port profile for LACP.
Before You Begin
Log in to the CLI in EXEC mode.
The default port channel mode is on.
Enable the LACP feature support before you configure LACP. This procedure has a step for enabling the LACP feature.
When you configure port channels with no associated aggregation protocol, know that all interfaces on both sides of the link remain in the on channel mode.
The LACP mode for individual links in an LACP port channel indicates that the link is allowed to operate with LACP.
Define a native VLAN for the trunk port. Although it may not be used for data, the native VLAN is used for LACP negotiation. If you want traffic forwarded on the native VLAN of the trunk port, the native VLAN must be in the allowed VLAN list and system VLAN list.
Procedure
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
switch(config)# feature lacp
Enables LACP support for port channels.
Step 3
switch(config-if)# port-profile [ type {ethernet | vethernet}] name
Enters port profile configuration mode for the named port profile.
name—Specifies the port profile name, which can be up to 80 characters and must be unique for each port profile on the .
type—(Optional) Specifies the port profile as an Ethernet or vEthernet type. Once configured, this setting cannot be changed. The default is the vEthernet type.
For configuring port channels, specify the port profile as an Ethernet type.
Defining a port profile as an Ethernet type allows the port profile to be used for physical (Ethernet) ports. In the vCenter Server, the corresponding port group can be selected and assigned to physical ports (PNICs).
Note
If a port profile is configured as an Ethernet type, it cannot be used to configure VMware virtual ports.
Designates the port profile as a VMware port group.
The port profile is mapped to a VMware port group of the same name unless you specify a name here. When you connect the VSM to vCenter Server, the port group is distributed to the virtual switch on the vCenter Server.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
This example shows how to remove a port channel group from a port profile:
switch# configure terminal
switch(config)# port-profile testProf
switch(config-port-prof)# no channel-group auto
switch(config-port-prof)# show port-profile testProf
switch(config-port-prof)#
Configuring VEM Management of LACP
You can offload management of LACP from the VSM to the VEMs.
Before You Begin
Log in to the CLI in EXEC mode.
After offloading the management of LACP from the VSM to the VEM, you must preserve the running configuration in the startup configuration and reload the VSM before the offload takes effect. This procedure has steps for doing this.
Offloading of LACP management to the VEMs is enabled by default on the VSM.
Note
If you have upgraded from a previous release, offloading of LACP management to the VEMs is disabled by default. You can enable or disable the feature using the [no] lacp offload command
Procedure
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
switch(config)# lacp offload
(Optional)
Offloads LACP management from the VSM to the VEMs.
If enabling LACP offload, a message displays to let you know that a reload is required.
Offload of LACP management to the VEMs is enabled by default.
Note
If you upgraded from a previous release, offload of LACP management to the VEMs is disabled by default.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
Step 4
switch(config)# show lacp offload status
(Optional)
Displays the LACP offload status for verification.
Note
The current status does not change to enabled until after a reload.
Step 5
switch(config)# reload
Reboots both the primary and secondary VSM.
Step 6
switch(config)# show lacp offload status
(Optional)
Displays the LACP offload status for verification.
Note
The current status does not change to enabled until after a reload.
This example shows how to offload management of LACP from the VSM to the VEMs:
switch# configure terminal
switch(config)# lacp offload
Please do a "copy running startup" to ensure the new setting takes effect on next reboot
LACP Offload Status can be verified using "show lacp offload status"
Change in LACP Offload Status takes effect only on the next VSM Reboot
This can potentially cause modules with LACP uplinks to flap
switch(config)# copy running-config startup-config
switch(config)# show lacp offload status
Current Status : Disabled
Running Config Status : Enabled
Saved Config Status : Enabled
switch(config)# reload
This command will reboot the system. (y/n)? [n] y
2010 Sep 3 11:33:35 n1000v %PLATFORM-2-PFM_SYSTEM_RESET: Manual system restart from Command Line Interface
n1000v(config)# show lacp offload status
Current Status : Enabled
Running Config Status : Enabled
Saved Config Status : Enabled
switch(config)#
Verifying the Port Channel Configuration
Use the following commands to verify the port channel configuration:
Command
Purpose
show feature
Displays the features available, and whether they are enabled.
show interface port-channelchannel-number
Displays the status of a port channel interface.
show lacp port-channel [interface port-channelchannel-number ]
Displays information about LACP port channels.
show lacp interface ethernetslot/port
Displays information about specific LACP interfaces.
show lacp offload status
Displays whether LACP management is offloaded to the VEMs.
Enabled—LACP is managed by VEMs.
Disabled—LACP is managed by the VSM.
show network-state tracking config
Displays the Network State Tracking configuration for verification.
show network-state tracking { modulemodID | interface channelID}
Displays the Network State Tracking status for a module or interface.
show port-channel compatibility-parameters
Displays the parameters that must be the same among the member ports in order to join a port channel.
show port-channel database [ interface port-channelchannel-number ]
Displays the aggregation state for one or more port channel interfaces.
show port-channel load-balance
Displays the type of load balancing in use for port channels.
show port-channel summary
Displays a summary for the port channel interfaces.
show port-channel traffic
Displays the traffic statistics for port channels.
show port-channel usage
Displays the range of used and unused channel numbers.
show running-config interface ethernetport/slot
Displays information about the running configuration of the specified Ethernet interface.
show running-config interface port-channel channel-number
Displays information about the running configuration of the port channel.
show running-config interface vethernetinterface-number
Displays information about the running configuration of the specified vEthernet interface.
Monitoring Port Channels
Use the following commands to monitor the port channel interface configuration:
Configuration Example: Create an LACP Port Channel
This example shows how to set the LACP-enabled interface to the active port channel mode for Ethernet interface 1/4 in channel group 5 and then configure an LACP port profile for the port channel:
switch# configure terminal
switch(config)# feature lacp
switch(config)# interface ethernet 1/4
switch(config-if)# channel-group 5 mode active
switch(config-if)# port-profile type ethernet system-uplink
switch(config-port-prof)# vmware port-group lacp
switch(config-port-prof)# switchport mode trunk
switch(config-port-prof)# switchport trunk allowed vlan 1-100
switch(config-port-prof)# channel-group auto mode active
switch(config-port-prof)# system vlan 1,10,20
switch(config-port-prof)# state enabled
switch(config-port-prof)# show port-channel summary
switch(config-port-prof)# copy running-config startup-config
Configuration Example: Configuring Network State Tracking for vPC-HM
This example shows how to configure Network State Tracking with an 8-second interval between sent broadcasts, with a maximum of 7 missed broadcasts before declaring a split network, and how to repin traffic to another uplink if a split network is detected: