Beginning in privileged EXEC mode, follow these steps to configure your switch as a PAgP physical-port learner and to adjust the priority so that the same port in the bundle is selected for sending packets. This procedure is optional.
To return the priority to its default setting, use the no pagp port-priority interface configuration command. To return the learning method to its default setting, use the no pagp learn-method interface configuration command. When enabled, LACP tries to configure the maximum number of LACP-compatible ports in a channel, up to a maximum of 16 ports. A maximum of eight LACP links can be active at one time. The software places any additional links in a hot-standby mode. If one of the active links becomes inactive, a link that is in the hot-standby mode becomes active in its place. If you configure more than eight links for an EtherChannel group, the software automatically decides which of the hot-standby ports to make active based on the LACP priority. The software assigns to every link between systems that operate LACP a unique priority made up of these elements (in priority order): •LACP system priority •System ID (a combination of the LACP system priority and the switch MAC address) •LACP port priority •Port number In priority comparisons, numerically lower values have higher priority. The priority decides which ports should be put in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating. Ports are considered for active use in aggregation in link-priority order starting with the port attached to the highest priority link. Each port is selected for active use if the preceding higher priority selections can also be maintained. Otherwise, the port is selected for standby mode. You can change the default values of the LACP system priority and the LACP port priority to affect how the software selects active and standby links. For more information, see the "Configuring the LACP System Priority" section and the "Configuring the LACP Port Priority" section. You can configure the system priority for all of the EtherChannels that are enabled for LACP by using the lacp system-priority global configuration command. You cannot configure a system priority for each LACP-configured channel. By changing this value from the default, you can affect how the software selects active and standby links. You can use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag). Beginning in privileged EXEC mode, follow these steps to configure the LACP system priority. This procedure is optional.
To return the LACP system priority to the default value, use the no lacp system-priority global configuration command. By default, all ports use the same port priority. If the local system has a lower value for the system priority and the system ID than the remote system, you can affect which of the hot-standby links become active first by changing the port priority of LACP EtherChannel ports to a lower value than the default. The hot-standby ports that have lower port numbers become active in the channel first. You can use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag). Note If LACP is not able to aggregate all the ports that are compatible (for example, the remote system might have more restrictive hardware limitations), all the ports that cannot be actively included in the EtherChannel are put in the hot-standby state and are used only if one of the channeled ports fails. Beginning in privileged EXEC mode, follow these steps to configure the LACP port priority. This procedure is optional.
To return the LACP port priority to the default value, use the no lacp port-priority interface configuration command. You can configure the maximum number of members that can be bundled. Any members in excess of this maximum number are kept in hot-standby state and are transitioned to bundled state when one of the bundled members goes down. To configure the LACP maximum number of ports to bundle in a port channel, complete these steps:
This example shows the maximum number of bundles is 1 on port channel 10. Switch# show running-config interface port-channel 10 Building configuration... Current configuration : 228 bytes Use this command to show the status of hot-standby interfaces. Switch# show etherchannel summary Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) U - in use f - failed to allocate aggregator M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated Number of channel-groups in use: 1 Group Port-channel Protocol Ports ------+-------------+-----------+--------------------------------------------- 10 Po10(SU) LACP Gi0/1(P) Gi0/3(H) Switch# show lacp internal Flags: S - Device is requesting Slow LACPDUs F - Device is requesting Fast LACPDUs A - Device is in Active mode P - Device is in Passive mode LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/1 SA bndl 32768 0xA 0xA 0x102 0x3D Gi0/3 FA hot-stby 32768 0xA 0xA 0x104 0x7 When a port from a hot-standby state moves to a bundled state, the default time is two seconds. Enabling fast switchover on the port channel changes this time to 50 ms. This faster time allows the port to quickly transition to the bundled state, and the port channel continues to stay up. To enable LACP fast switchover on a port channel, complete these steps:
Use the commands in these examples to show that fast switchover is enabled. Switch# show etherchannel 10 port-channel Port-channels in the group: Port-channel: Po6 (Primary Aggregator) Age of the Port-channel = 0d:01h:54m:42s Logical slot/port = 14/3 Number of ports = 1 Port state = Port-channel Ag-Inuse Fast-switchover = enabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- Time since last port bundled: 0d:01h:54m:03s Fa2/44 Switch# show etherchannel 10 detail Port-channels: 1 Max Port-channels = 16 Port-channels in the group: Port-channel: Po6 (Primary Aggregator) Age of the Port-channel = 0d:02h:14m:09s Logical slot/port = 14/3 Number of ports = 1 Port state = Port-channel Ag-Inuse Fast-switchover = enabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- Time since last port bundled: 0d:02h:13m:30s Fa2/44 To assist with early detection of a member link failure, you can request the peer to send LACPDUs at a rate of one second. The default rate is 30 seconds. To enable LACP fast rate, complete these steps:
This example shows that fast rate is configured. Switch# show lacp internal Flags: S - Device is requesting Slow LACPDUs F - Device is requesting Fast LACPDUs A - Device is in Active mode P - Device is in Passive mode LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/1 FA bndl 32768 0xA 0xA 0x102 0x7D The EtherChannel min-links feature is supported on LACP EtherChannels. This feature allows you to configure the minimum number of member ports that must be in the link-up state and bundled in the EtherChannel for the port channel interface to transition to the link-up state. You can use the EtherChannel min-links feature to prevent low-bandwidth LACP EtherChannels from becoming active. This feature also causes LACP EtherChannels to become inactive if they have too few active member ports to supply your required minimum bandwidth. In addition, when LACP max-bundle values are specified in conjunction with min-links, the configuration is verified and an error message is returned if the min-links value is not compatible with (equal to or less than) the max-bundle value. To configure the EtherChannel min-links feature, perform this task:
Use the no port-channel min-links number command to restore default etherchannel min-links configuration. Where a bundle fails to meet the criteria for min-link configuration an error message is displayed. Use the show etherchannel port-channel interface detail command to display additional information not provided in the error message to determine the reason for the failure. Note Although the EtherChannel min-links feature works correctly when configured only on one end of an EtherChannel, for best results, configure the same number of minimum links on both ends of the EtherChannel. This example shows how to configure port channel interface 1 to be inactive if fewer than two member ports are active in the EtherChannel: Switch# configure terminal Switch(config)# interface port-channel 1 Switch(config-if)# port-channel min-links 2 This example shows the output from the show etherchannel port-channel interface detail command: Switch# show etherchannel 10 detail Port-channels: 1 Max Port-channels = 16 Port state = Up Mstr In-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = Po10 GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/12 SA bndl 32768 0xA 0xA 0x10D 0x3D Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/12 SA bndl 32768 0x0 0xA 0x114 0x3D Age of the port in the current state: 1d:00h:24m:51s Port state = Up Mstr In-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = Po10 GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/13 SA bndl 32768 0xA 0xA 0x10E 0x3D Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/13 SA bndl 32768 0x0 0xA 0x104 0x3D Age of the port in the current state: 1d:00h:24m:48s Port state = Up Mstr In-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = Po10 GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/20 SA bndl 32768 0xA 0xA 0x115 0x3D Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/20 SA bndl 32768 0x0 0xA 0x115 0x3D Age of the port in the current state: 1d:00h:24m:43s Port-channels in the group: Port-channel: Po10 (Primary Aggregator) Age of the Port-channel = 1d:00h:36m:54s Logical slot/port = 2/10 Number of ports = 3 Port state = Port-channel Ag-Inuse Fast-switchover = disabled Direct Load Swap = disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+--------+------------------+----------- Time since last port bundled: 1d:00h:24m:43s Gi0/20 Time since last port Un-bundled: 1d:00h:24m:45s Gi0/20 Last applied Hash Distribution Algorithm: - Channel-group Iedge Counts: --------------------------: +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 009215: 1d00h: %EC-5-MINLINKS_NOTMET: Port-channel Po10 is down bundled ports (2) doesn't meet min-links <<<<<<<<<<< Error message thrown on member 009216: 1d00h: %LINK-3-UPDOWN: Interface Port-channel10, changed state to down Link Failure 009217: 1d00h: %LINK-3-UPDOWN: Interface GigabitEthernet0/20, changed state to down 009218: 1d00h: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/20, changed state to down 009219: 1d00h: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/12, changed state to down 009220: 1d00h: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/13, changed state to down 009221: 1d00h: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel10, changed state to down ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Switch# show etherchannel 10 detail Port-channels: 1 Max Port-channels = 16 Port state = Up Mstr In-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = Po10 GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/12 SA bndl 32768 0xA 0xA 0x10D 0x3D Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/12 SA bndl 32768 0x0 0xA 0x114 0x3D Age of the port in the current state: 1d:00h:26m:00s Port state = Up Mstr In-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = Po10 GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/13 FA bndl 32768 0xA 0xA 0x10E 0x3D Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/13 SA bndl 32768 0x0 0xA 0x104 0xF Age of the port in the current state: 1d:00h:25m:57s Port state = Down Not-in-Bndl Channel group = 10 Mode = Active Gcchange = - Port-channel = null GC = - Pseudo port-channel = Po10 Port index = 0 Load = 0x00 Protocol = LACP Flags: S - Device is sending Slow LACPDUs F - Device is sending fast LACPDUs. A - Device is in active mode. P - Device is in passive mode. LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/20 SA down 32768 0xA 0xA 0x115 0x7 Partner Partner LACP Partner Partner Partner Partner Partner Port Flags State Port Priority Admin Key Oper Key Port Number Port State Gi0/20 FP down 32768 0x0 0xA 0x115 0x34 Age of the port in the current state: 1d:00h:25m:51s Port-channels in the group: Port-channel: Po10 (Primary Aggregator) Age of the Port-channel = 1d:00h:38m:03s Logical slot/port = 2/10 Number of ports = 2 Port state = Port-channel Ag-MinLink-Not-Inuse <<<<<<<<<<<<<< Reason as to why the link is down Fast-switchover = disabled Direct Load Swap = disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+--------+------------------+----------- Time since last port bundled: 1d:00h:25m:51s Gi0/20 Time since last port Un-bundled: 0d:00h:00m:10s Gi0/20 Last applied Hash Distribution Algorithm: - Channel-group Iedge Counts: --------------------------: For an LACP or PAgP port to peer with a neighbor on a port that has an Ethernet Virtual Connection (EVC) EFP service instance configured, you need to enter the l2 protocol peer lacp or l2 protocol peer lacp service-instance configuration command on the service instance. See the "Configuring Ethernet Virtual Connections (EVCs)" chapter for more information on EFPs. This example shows how to configure Layer 2 protocol LACP peer on a service instance: Switch (config)# interface gigabitethernet0/1 Switch (config-if)# switchport mode trunk Switch (config-if)# switchport trunk allowed vlan none Switch (config-if)# service instance 1 Ethernet Switch (config-if-srv)# encapsulation untagged Switch (config-if-srv)# l2protocol peer lacp Switch (config-if-srv)# bridge-domain 10 Switch (config-if-srv)# end To display EtherChannel, PAgP, and LACP status information, use the privileged EXEC commands described in Table 36-4:
You can clear PAgP channel-group information and traffic counters by using the clear pagp {channel-group-number counters | counters} privileged EXEC command. You can clear LACP channel-group information and traffic counters by using the clear lacp {channel-group-number counters | counters} privileged EXEC command. For detailed information about the fields in the displays, see the command reference for this release. |