Single sided VPC configuration Example

Below is the single side VPC configuration example. In the below example 7Ks are configured in VPC so that downstream switch i.e 5K will believe that it is connected to only one upstream switch.

Note:- VPC configuration will only be done on the 7Ks not on the 5K as for 5K it is just a normal port channel.

As we know to create VPC we need two type of connectivity as mentioned below:-

1.VPC peer-link

VPC peer-link can only be configured on the layer-2 port-channel containing Ten-gig links. It cannot be configured on physical interfaces. For complete redundancy we should chose interfaces from different modules and must contain more than one interface.

VPC peer-link command is used to convert the port-channel to peer-link.

2.VPC peer-keepalive link

VPC peer-keepalive link is a L3 interface and it is just a backup to the peer-link but it will not pass any user traffic. Only hello packets are exchange over keepalive link. There is no impact if the peer-keepalive link is down and peer-link is up.

VPC peer-keepalive link can be configured using management interface or any L3 interface in default or any other VRF. Cisco recommends to use a dedicated vrf for peer keepalaive link.

N7K-1:-

Step1:- Enable Feature VPC

N7K-1(config)# feature vpc

Step 2:- Enable Feature LACP

N7K-1(config)# feature lacp

Step 3:- Create VPC domain. Make sure it is same on the VPC peer otherwise VPC will remain in down state.

N7K-1(config-if-range)# vpc domain 100 N7K-1(config-vpc-domain)# peer-keepalive destination 10.1.1.72 --<< Mgmt IP of N7K-2 Note:  --------:: Management VRF will be used as the default VRF ::--------

We get the below output if domain Id are different on peers switches.

N7K-1(config)# show vpc brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 100 Peer status                       : peer link not configured vPC keep-alive status             : peer is alive, but domain IDs do not match  -----<<<<<<<<<<<<<< Configuration consistency status  : failed Per-vlan consistency status       : failed Configuration inconsistency reason: vPC peer-link does not exist Type-2 consistency status         : failed Type-2 inconsistency reason       : vPC peer-link does not exist vPC role                          : none established Number of vPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Disabled (due to peer configuration) Auto-recovery status              : Disabled

We get below output when peer switches are reachable via peer keepalive link.

N7K-1(config-vpc-domain)# show vpc brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 100 Peer status                       : peer link not configured -<< vPC keep-alive status             : peer is alive  -----<<< Configuration consistency status  : failed Per-vlan consistency status       : failed Configuration inconsistency reason: vPC peer-link does not exist  ---<<<<<<<<< Type-2 consistency status         : failed Type-2 inconsistency reason       : vPC peer-link does not exist vPC role                          : none established Number of vPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Disabled (due to peer configuration) Auto-recovery status              : Disabled

Step 4:- Create port-channel for vpc peer-link. As soon as VPC PEER-LINK command is configured on

port channel the port type is changed to network and bridge assurance is enabled on the port-channel.

N7K-1(config)# int eth1/1-2 N7K-1(config-if-range)# channel-group 1 mode active N7K-1(config-if-range)# no shut N7K-1(config-if-range)# int po1 N7K-1(config-if)# switchport mode trunk N7K-1(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N7K-1(config-if)# no shut

Step 5:- Configure port-channel connected to 5K.

N7K-1(config)# int eth1/3 N7K-1(config-if-range)# channel-group 10 mode active N7K-1(config-if-range)# no shut N7K-1(config-if-range)# int po10 N7K-1(config-if)# switchport mode trunk N7K-1(config-if)#vpc10

N7K-2:-

Step 6:- Enable vpc and lacp feature

N7K-2(config)# feature vpc N7K-2(config)# feature lacp

Step7:- Configure VPC Domain and vpc peer-keepalive link.

N7K-2(config-if-range)# vpc domain 100 N7K-2(config-vpc-domain)# peer-keepalive destination 10.1.1.71 --<< Mgmt IP of N7K-1 Note:  --------:: Management VRF will be used as the default VRF ::--------

Step8:- Configure VPC peer-link

N7K-2(config)# int eth1/1-2 N7K-2(config-if-range)# channel-group 1 mode active N7K-2(config-if-range)# no shut N7K-2(config-if-range)# int po1 N7K-2(config-if)# switchport mode trunk N7K-2(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N7K-2(config-if)# no shut

Step9:- Configure vpc port-channel connected to N5k

N7K-2(config)# int eth1/3 N7K-2(config-if-range)# channel-group 10 mode active N7K-2(config-if-range)# no shut N7K-2(config-if-range)# int po10 N7K-2(config-if)# switchport mode trunk N7K-2(config-if)#vpc10

N5K-1:-

Step10:- Enable LACP feature

N5K-1(config)# feature lacp

Step 11:- Configure port-channel connected to 7Ks.

N7K-2(config)# int eth1/1-2 N7K-2(config-if-range)# channel-group 1 mode active N7K-2(config-if-range)# no shut N7K-2(config-if-range)# int po1 N7K-2(config-if)# switchport mode trunk

Note: - There is no need to configure VPC on 5K. As for 5K it just another port channel going to uplink switch.

Verification:-

VPC peering is up when both side peer-link and keepalive links are up as shown below.

N7K-1(config-if)# show vpc brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 100 Peer status                       : peer adjacency formed ok vPC keep-alive status             : peer is alive Configuration consistency status  : success Per-vlan consistency status       : success Type-2 inconsistency reason       : Consistency Check Not Performed vPC role                          : primary Number of vPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Enabled Auto-recovery status              : Disabled vPC Peer-link status --------------------------------------------------------------------- id   Port   Status Active vlans --   ----   ------ -------------------------------------------------- 1    Po1    up     1

VPC can be verified using show vpc role command. ROLE PRIORITY command under VPC domain can be used to change the VPC role but bouncing of VPC peer link is required to apply the new configured priority.

N7K-1(config-if)# show vpc role vPC Role status ---------------------------------------------------- vPC role                        : primary Dual Active Detection Status    : 0 vPC system-mac                  : 00:23:04:ee:be:64 vPC system-priority             : 32667 vPC local system-mac            : 00:26:98:0d:3c:c4 vPC local role-priority         : 32667

Below command can show the status of the peer-keepalive link and its statistics.

N7K-1(config-if)# show vpc peer-keepalive vPC keep-alive status             : peer is alive --Peer is alive for             : (8525) seconds, (220) msec --Send status                   : Success --Last send at                  : 2014.12.19 17:55:30 978 ms --Sent on interface             : mgmt0 --Receive status                : Success --Last receive at               : 2014.12.19 17:55:30 978 ms --Received on interface         : mgmt0 --Last update from peer         : (0) seconds, (139) msec vPC Keep-alive parameters --Destination                   : 10.1.1.72 --Keepalive interval            : 1000 msec --Keepalive timeout             : 5 seconds --Keepalive hold timeout        : 3 seconds --Keepalive vrf                 : management --Keepalive udp port            : 3200 --Keepalive tos                 : 192

Below command shows the consistency check between the VPC peers. Peer with Consistency type-1 are not allowed to make pair.

N7K-1(config-if)# show vpc consistency-parameters global     Legend:         Type 1 : vPC will be suspended in case of mismatch Name                        Type  Local Value            Peer Value -------------               ----  ---------------------- ----------------------- STP Mode                    1     Rapid-PVST             Rapid-PVST STP Disabled                1     None                   None STP MST Region Name         1     ""                     "" STP MST Region Revision     1     0                      0 STP MST Region Instance to  1  VLAN Mapping STP Loopguard               1     Disabled               Disabled STP Bridge Assurance        1     Enabled                Enabled STP Port Type, Edge         1     Normal, Disabled,      Normal, Disabled, BPDUFilter, Edge BPDUGuard        Disabled               Disabled STP MST Simulate PVST       1     Enabled                Enabled Allowed VLANs               -     1                      1 Local suspended VLANs       -     -                      -

Particular vpc port-channel consistency parameter can also been seen using below command.

N7K.;-1(config-if)# show vpc consistency-parameters interface po10     Legend:         Type 1 : vPC will be suspended in case of mismatch Name                        Type                      Local Value                                Peer Value -------------               ----  ---------------------- ----------------------- STP Port Type               1                         Default                                       Default STP Port Guard              1                        None                                          None STP MST Simulate PVST       1                Default                                       Default lag-id                      1                                 [(7f9b,                                         [(7f9b,                                                             0-23-4-ee-be-64, 800a,                   0-23-4-ee-be-64, 800a,                                                             0, 0), (8000,                                       0, 0), (8000,                                                              0-5-73-ca-90-1, 13, 0,                    0-5-73-ca-90-1, 13, 0,                                                                       0)]                                             0)] mode                        1                                 active                                       active Speed                       1                                10 Gb/s                                       10 Gb/s Duplex                      1                                 full                                             full Port Mode                   1                            trunk                                           trunk Native Vlan                 1                                 1                                             1 MTU                         1                               1500                                          1500 Allowed VLANs               -                     1-4094                                          1-4094 Local suspended VLANs       -                     -                                                   -

VPC - Back-to-Back configuration example

Below is the VPC Back-to-Back  configuration example.

N7K-1:-

Step1:- Enable Feature VPC

N7K-1(config)# feature vpc

Step 2:- Enable Feature LACP

N7K-1(config)# feature lacp

Step 3:- Create VPC domain. Make sure it is same on the VPC peer otherwise VPC will remain in down state.

N7K-1(config-if-range)# vpc domain 100 N7K-1(config-vpc-domain)# peer-keepalive destination 10.1.1.72 --<< Mgmt IP of N7K-2 Note:  --------:: Management VRF will be used as the default VRF ::--------

We get the below output if domain Id are different on peers switches.

N7K-1(config)# show vpc brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 100 Peer status                       : peer link not configured vPC keep-alive status             : peer is alive, but domain IDs do not match  -----<<<<<<< Configuration consistency status  : failed Per-vlan consistency status       : failed Configuration inconsistency reason: vPC peer-link does not exist Type-2 consistency status         : failed Type-2 inconsistency reason       : vPC peer-link does not exist vPC role                          : none established Number of vPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Disabled (due to peer configuration) Auto-recovery status              : Disabled

We get below output when peer switches are reachable via peer keepalive link.

N7K-1(config-vpc-domain)# show vpc brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 100 Peer status                       : peer link not configured  --------------<<<<<<<<<<<<<<<<<<< vPC keep-alive status             : peer is alive  ----------------<<<<<<<<<<<<<<< Configuration consistency status  : failed Per-vlan consistency status       : failed Configuration inconsistency reason: vPC peer-link does not exist  ---<<<<<<<<< Type-2 consistency status         : failed Type-2 inconsistency reason       : vPC peer-link does not exist vPC role                          : none established Number of vPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Disabled (due to peer configuration) Auto-recovery status              : Disabled

Step 4:- Create port-channel for vpc peer-link. As soon as VPC PEER-LINK command is configured on

port channel the port type is changed to network and bridge assurance is enabled on the port-channel.

N7K-1(config)# int eth1/1-2 N7K-1(config-if-range)# channel-group 1 mode active N7K-1(config-if-range)# no shut N7K-1(config-if-range)# int po1 N7K-1(config-if)# switchport mode trunk N7K-1(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N7K-1(config-if)# no shut

Step 5:- Configure port-channel connected to 5Ks. Make sure all the interfaces connected to 5Ks are in same port channel.

N7K-1(config)# int eth1/3-4 N7K-1(config-if-range)# channel-group 10 mode active N7K-1(config-if-range)# no shut N7K-1(config-if-range)# int po10 N7K-1(config-if)# switchport mode trunk N7K-1(config-if)#vpc10

N7K-2:-

Step 6:- Enable vpc and lacp feature

N7K-2(config)# feature vpc N7K-2(config)# feature lacp

Step7:- Configure VPC Domain and vpc peer-keepalive link.

N7K-2(config-if-range)# vpc domain 100 N7K-2(config-vpc-domain)# peer-keepalive destination 10.1.1.71 --<< Mgmt IP of N7K-1 Note:  --------:: Management VRF will be used as the default VRF ::--------

Step8:- Configure VPC peer-link

N7K-2(config)# int eth1/1-2 N7K-2(config-if-range)# channel-group 1 mode active N7K-2(config-if-range)# no shut N7K-2(config-if-range)# int po1 N7K-2(config-if)# switchport mode trunk N7K-2(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N7K-2(config-if)# no shut

Step9:- Configure vpc port-channel connected to N5k

N7K-2(config)# int eth1/3-4 N7K-2(config-if-range)# channel-group 10 mode active N7K-2(config-if-range)# no shut N7K-2(config-if-range)# int po10 N7K-2(config-if)# switchport mode trunk N7K-2(config-if)#vpc10

N5K-1:-

Step 10:- Enable vpc and lacp feature

N5K-1(config)# feature vpc N5K-1(config)# feature lacp

Step 11:- Configure VPC Domain and vpc peer-keepalive link.

N5K-1(config-if-range)# vpc domain 100 N5K-1(config-vpc-domain)# peer-keepalive destination 10.1.1.52 --<< Mgmt IP of N5K-2 Note:  --------:: Management VRF will be used as the default VRF ::--------

Step12:- Configure VPC peer-link

N5K-1(config)# int eth1/1-2 N5K-1(config-if-range)# channel-group 1 mode active N5K-1(config-if-range)# no shut N5K-1(config-if-range)# int po1 N5K-1(config-if)# switchport mode trunk N5K-1(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N5K-1(config-if)# no shut

Step13:- Configure vpc port-channel connected to N7ks and port channel number must be same on both 5K. Make sure port channel number on 7k and 5K should be different.

For example we have chosen po10 on 7K and po20 on 5K.

N5K-1(config)# int eth1/3-4 N5K-1 (config-if-range)# channel-group 20 mode active N5K-1 (config-if-range)# no shut N5K-1 (config-if-range)# int po20 N5K-1 (config-if)# switchport mode trunk N5K-1 (config-if)#vpc 20

N5K-2:-

Step 14:- Enable vpc and lacp feature

N5K-1(config)# feature vpc N5K-1(config)# feature lacp

Step 15:- Configure VPC Domain and vpc peer-keepalive link.

N5K-1(config-if-range)# vpc domain 100 N5K-1(config-vpc-domain)# peer-keepalive destination 10.1.1.51 --<< Mgmt IP of N5K-1 Note:  --------:: Management VRF will be used as the default VRF ::--------

Step12:- Configure VPC peer-link

N5K-2(config)# int eth1/1-2 N5K-2(config-if-range)# channel-group 1 mode active N5K-2(config-if-range)# no shut N5K-2(config-if-range)# int po1 N5K-2(config-if)# switchport mode trunk N5K-2(config-if)# vpc peer-link Please note that spanning tree port type is changed to "network" port type on vPC peer-link. This will enable spanning tree Bridge Assurance on vPC peer-link provided the STP Bridge Assurance (which is enabled by default) is not disabled. N5K-2(config-if)# no shut

Step13:- Configure vpc port-channel connected to N7ks .

N5K-2(config)# int eth1/3-4 N5K-2(config-if-range)# channel-group 20 mode active N5K-2(config-if-range)# no shut N5K-2(config-if-range)# int po20 N5K-2(config-if)# switchport mode trunk N5K-2(config-if)#vpc 20

What is Zoning - Storage 12

Zoning is way to restrict the communication between the initiator and the targets. By using Zoning only assigned target is visible to the initiator.

 In Ethernet, host connected to LAN is able to see all the devices connected on the same vlan but in VSAN there is another layer of restriction called zoning to restrict the visibility between initiator and targets. Devices within a zone can able see each other.

There are two types of Zoning available.

1.  Hard Zoning:- It is implemented at the ASIC level and hence devices cannot communicate if hard zoning is a restricting the communication.

It not only creates a barrier to the visibility between devices but also restrict the data transfer between the ports in different zones. It restricts both control and data plane traffic.

Zoning done on the basis of the switchport are called port-based zoning. Sometimes hard zoning also known as port-based zoning.

It can be one of the below three types:-

·  One to one:- Initiator and target are mapped in single zoning configuration and hence initiator can only see one target.

·  One to many:- Initiator and many target are in one zone. Hence many targets are visible to the initiator.

·  Many to many:- Many initiator and many targets are in one zone. A single port can be configured on multiple targets.

Advantage: -

Ø  As it is implemented on the ASIC hardware level, it provides higher level of security as the data can be sent between the ports on same zone only. No data will be allowed to between the hosts of different zone.

Ø  It increases the routing performance as the zoning is applied at the hardware level.

Disadvantage: -

Ø  It is not a flexible solution as devices must be connected to the same port in order to communicate the other devices in the zone. In case of port failure, zoning must be changed on all the switches in the fabric which is a difficult task in large environment.

2.  Soft Zoning:- Zoning based on PWWN and NWWN are known as soft zoning. It is implemented on the operating system level. It only restricts the control packet information not the data plane.

As soon as a device is connected to the fabric, it sends a request to name service about all the devices present in the same zone.

Advantage:-

Ø  It is very flexible as compared to hard zoning.

Disadvantage:-

Ø  Device will not see any devices in other zones. By any chance if the device knows the destination and send the FC frame to the target then Software zoning has no way to restrict the communication.  As a result it is less secure than hard zoning.

Note:- MDS 9000 supports both hard and soft zoning.

Port Types - Storage 11

Below are most common port types in storage.

1. N-Port (Node Port):- Port on the end host device like storage (target) or server (initiator). N-port cannot be configured on the switch side.

2. NL-Port (Node Loop port):- Host that are connected in Arbitrated loop has the NL port.

3. F-port (Fabric Port):- Switchport that are connected to N-port are configured as F-port.

4. FL-Port (Fabric Loop port):- Switchport connected to NL port are configured with FL port.

5. E-Port (Expansion Port):- Port between the switches is configured as E-port. Expansion ports are similar to trunk port in Ethernet. Also known as ISL (Inter switch-link).

6. TE-port (Trunk expansion port):-  It is known as extended ISL which is analogous to 802.1Q to allow multiple VSANs on the E-port. There is no configuration to make a TE port. It is automatically configured as soon as multiple VSANS are configured on a switch.

7. TN-Port (Trunk Node Port):- N-port of hosts that support multiple VSANS are known as TN port. Need of trunk F-port is required in case when host device supports multiple vsan at a time like ESX.

8. TF-Port (Trunk Fabric Port):- Switchport connected to TN port is configured as TF port.

Fibre channel Addressing - Storage 10

1. World Wide Node Name (WWNN):- Sometimes it is also called as NWWN (Node World Wide Name).It is an 8-byte address used to identify device in the fabric.Every device in Fabric has its own WWNN.

No device can have two WWNN. Each node or HBA has one WWNN. If a server has two HBA then they have two WWNN.

2. World Wide Port Name (WWPN):- Also known as PWWN (Port World Wide Name). It is used to identify port on a device (switch or HBA card). Each port on a device has its own PWWN. It is also 8-Byte address.

3. Fabric Assigned Port World Wide Name (FAPWWN):-Some vendors like IBM also support Virtual PWWN called FAPWWN. These can be used to pre-configure the Zoning in order to increase the deployment efficiency.

4. Fabric Channel ID:- Referred to as FCID. Since there is a potential problem if 64 bits PWWN is used for routing, FC has used another address scheme.  FCID is used by the data plane to switch the traffic. FCID persistence is enabled by default to make sure it will not change after the device reboot.

FCID is 24 bit or 3 byte address assigned automatically to each port by switch. A switch can have different FCIDs for different VSANs.

FCID can be manually or dynamically assigned. Some HBAs doesn't allow the targets in the same area, static assignment can be useful in such scenario.

MDS-01# config t MDS-01(config)# fcdomain fcid database MDS-01(config-fcid-db)# vsan 100 wwn 00:00:00:00:00:00:00:01 fcid 0x010101

FCID is made up of three fields:-

• Domain ID: - It is the most significant byte that is a unique identifier assigned to each switch in a fabric. We can have 2 ^8 = 256 address available but few addresses are reserved and hence only 239 addresses can be used. It can either be assigned manually or dynamically.

   Domains ID are assigned by the Principle switch. PS is nothing but a general switch in the fabric that is responsible to assign the Domain IDs. Please refer to the below blog to find the more details about the Domain ID.

• Area ID: - It gives 2^8=256 addresses. In director switches there can be more than 256 switchport. And hence Area ID is the shared between the groups of ports. It cannot be configured and automatically configured by switches. 

• Port ID: - It is used to identify individual ports connected to N or NL port.

VTP type-2 configuration incompatible error in Cisco Nexus switch

If we get VTP type-2 configuration incompatible error in show VPC brief command as shown below.

N7K-6-2(config)# show vPC brief Legend:                 (*) - local vPC is down, forwarding via vPC peer-link vPC domain id                     : 10 Peer status                       : peer adjacency formed ok vPC keep-alive status             : peer is alive Configuration consistency status  : success Per-vlan consistency status       : success Type-2 consistency status         : failed Type-2 inconsistency reason       : VTP type-2 configuration incompatible ---<<<<< vPC role                          : primary Number of VPCs configured         : 0 Peer Gateway                      : Disabled Dual-active excluded VLANs        : - Graceful Consistency Check        : Enabled Auto-recovery status              : Disabled vPC Peer-link status --------------------------------------------------------------------- id   Port   Status Active vlans --   ----   ------ -------------------------------------------------- 1    Po10   up     1,20

Then please make sure VTP version, domain, mode and password is same on the peers.

N7K-6-2# show vpc consistency-parameters interface po10 Note: **** Global type-1 parameters will be displayed for peer-link *****     Legend:         Type 1 : vPC will be suspended in case of mismatch Name                        Type  Local Value            Peer Value -------------               ----  ---------------------- ----------------------- STP Mode                    1     Rapid-PVST             Rapid-PVST STP Disabled                1     None                   None STP MST Region Name         1     ""                     "" STP MST Region Revision     1     0                      0 STP MST Region Instance to  1  VLAN Mapping STP Loopguard               1     Disabled               Disabled STP Bridge Assurance        1     Enabled                Enabled STP Port Type, Edge         1     Normal, Disabled,      Normal, Disabled, BPDUFilter, Edge BPDUGuard        Disabled               Disabled STP MST Simulate PVST       1     Enabled                Enabled VTP domain                  2     lab                    test                ---------------<<<<<< VTP version                 2     1                      1 VTP mode                    2     Server                 Server          ---------------<<<<<< VTP password                2     lab123               test             ----------------<<<<<< VTP pruning status          2     Disabled               Disabled Allowed VLANs               -     1                      1 Local suspended VLANs       -     -                      -

Even if you see the errors then try below steps:- 

1.       Disable and re-enable the VTP feature.

2.       Reconfigure the VTP password.

3.       Change the mode to server to client then back to server.

4.       Also check the layer-2 connectivity between the peers via peer link. It could be a problem with one or more of the peer link member port. Check for errors on the physical link of the peer link port-channel.