Cisco MDS 9000 Family Cookbook, Release 1.x
Logical Interfaces
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Table Of Contents

Logical Interfaces

Creating a PortChannel

Adding a New Member to a PortChannel

Removing a Member from a PortChannel

Modifying the VSAN Allowed List


Logical Interfaces

PortChannels allow for the aggregation of multiple Fibre Channels or FCIP links into a single, high- speed, fault tolerant Fibre Channel or FCIP ISL (Inter-Switch Link). An ISL with multiple Fibre Channels or FCIP links has the same configuration options as a single-link Fibre Channel or FCIP ISL. This chapter focuses on the procedures associated with building, modifying, and reducing a PortChannel. It includes the following sections:

•Creating a PortChannel

•Adding a New Member to a PortChannel

•Removing a Member from a PortChannel

•Modifying the VSAN Allowed List

Creating a PortChannel

There are two basic methods to create a PortChannel: using the Fabric Manager wizard or entering commands through the CLI (command-line interface). This procedure shows how to create a PortChannel using the CLI.

This procedure uses the following resources:

Switch 1:

Channel Group 2

Interfaces: fc1/1 and fc2/1

Switch 2:

Channel Group 2

Interfaces: fc1/1 and fc2/1

Allowed VSANs: 1,10

Figure 4-1 Topology

Tip•A PortChannel should use interfaces on multiple line cards to protect the PortChannel against line card failure.

•The same channel group number should be used on both ends of a PortChannel. Having the same number helps in troubleshooting and identifying the corresponding channel group on the other switch.

•A PortChannel, like all other interfaces, can have a description. Use the description field to specify exactly where the PortChannel goes.

•PortChannels can use any port on the switch and connect to any other port on a switch.

•Set the initial VSAN allowed list prior to bringing up the PortChannel. This action prevents any VSANs from merging when you bring up the PortChannel the first time.

To create a PortChannel through the CLI, follow these steps:

Step 1 Create the PortChannel on switch 1. 

switch1# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch1(config)# interface fc1/1, fc2/1

switch1(config-if)# channel-group 2

fc1/1 fc2/1 added to port-channel 2 and disabled

please do the same operation on the switch at the other end of the port-channel,

then do "no shutdown" at both ends to bring them up

switch1(config-if)# switchport description "To switch2 PortChannel2"

Step 2 Enable trunking (TE) and set the VSAN allowed list on switch 1. 

switch1# config terminal

switch1(config)# int port-channel 2

switch1(config-if)# switchport trunk mode on

switch1(config-if)# switchport trunk allowed vsan 1

switch1(config-if)# switchport trunk allowed vsan add 10

Step 3 Create the PortChannel and set the description on switch 2. 

switch2# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch2(config)# interface fc1/1, fc2/1

switch2(config-if)# channel-group 2

fc1/1 fc2/1 added to port-channel 2 and disabled

please do the same operation on the switch at the other end of the port-channel,

then do "no shutdown" at both ends to bring them up

switch2(config-if)# switchport description "To switch1 PortChannel2"

Step 4 Enable trunking (TE) and set the VSAN allowed list on switch 2. 

switch2# config terminal

switch2(config)# int port-channel 2

switch2(config-if)# switchport trunk mode on

switch2(config-if)# switchport trunk allowed vsan 1

switch2(config-if)# switchport trunk allowed vsan add 10

Step 5 Enable the interfaces to bring up the PortChannel.

a. Switch 1 

switch1# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch1(config)# interface fc1/1, fc2/1

switch1(config-if)# no shut

b. Switch 2 

switch2# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch2(config)# interface fc1/1, fc2/1

switch2(config-if)# no shut

Step 6 Verify that the PortChannel came up. 

switch1# show interface port-channel 2

port-channel 2 is trunking

    Port description is To switch2 PortChannel2

    Hardware is Fibre Channel

    Port WWN is 24:02:00:0c:85:e9:d2:c0

    Admin port mode is E, trunk mode is on

    Port mode is TE

    Port vsan is 1

    Speed is 4 Gbps

    Trunk vsans (admin allowed and active) (1,10)

    Trunk vsans (up)                       (1,10)

    Trunk vsans (isolated)                 ()

    Trunk vsans (initializing)             ()

    5 minutes input rate 64 bits/sec, 8 bytes/sec, 0 frames/sec

    5 minutes output rate 56 bits/sec, 7 bytes/sec, 0 frames/sec

      78296342 frames input, 72311141128 bytes

        0 discards, 0 errors

        0 CRC,  0 unknown class

        0 too long, 0 too short

      56299070 frames output, 26061293700 bytes

        0 discards, 0 errors

      0 input OLS, 2 LRR, 0 NOS, 0 loop inits

      4 output OLS, 2 LRR, 0 NOS, 0 loop inits

    Member[1] : fc1/1

    Member[2] : fc2/1

    iSCSI authentication: None

Adding a New Member to a PortChannel

This procedure uses the following resources:

Switch 1:

Channel Group 2

Existing Interfaces: fc1/1 and fc2/1

New Interfaces: fc3/1

Switch 2:

Channel Group 2

Existing Interfaces: fc1/1 and fc2/1

New Interface: fc3/1

To add a member to an existing PortChannel, follow these steps:

Step 1 To add the new member to switch 1, use the force keyword to have the new link inherit the parameters of the existing link. 

switch1# conf t

switch1(config)# int fc3/1

switch1(config-if)# channel-group 2 force

fc3/1 added to port-channel 2 and disabled

please do the same operation on the switch at the other end of the port-channel,

then do "no shutdown" at both ends to bring them up

switch1(config-if)# no shut

Step 2 To add the new member to switch 2, use the force keyword to have the new link inherit the parameters of the existing link. 

switch2# conf t

switch2(config)# int fc3/1

switch2(config-if)# channel-group 2 force

fc3/1 added to port-channel 2 and disabled

please do the same operation on the switch at the other end of the port-channel,

then do "no shutdown" at both ends to bring them up

switch3(config-if)# no shut

Step 3 Verify that the PortChannel now has all three members. 

switch1# show interface port-channel 2

port-channel 2 is trunking

    Port description is To switch2 PortChannel2

    Hardware is Fibre Channel

    Port WWN is 24:02:00:0c:85:e9:d2:c0

    Admin port mode is E, trunk mode is on

    Port mode is TE

    Port vsan is 1

    Speed is 6 Gbps

    Trunk vsans (admin allowed and active) (1,10)

    Trunk vsans (up)                       (1,10)

    Trunk vsans (isolated)                 ()

    Trunk vsans (initializing)             ()

    5 minutes input rate 64 bits/sec, 8 bytes/sec, 0 frames/sec

    5 minutes output rate 56 bits/sec, 7 bytes/sec, 0 frames/sec

      78296342 frames input, 72311141128 bytes

        0 discards, 0 errors

        0 CRC,  0 unknown class

        0 too long, 0 too short

      56299070 frames output, 26061293700 bytes

        0 discards, 0 errors

      0 input OLS, 2 LRR, 0 NOS, 0 loop inits

      4 output OLS, 2 LRR, 0 NOS, 0 loop inits

    Member[1] : fc1/1

    Member[2] : fc2/1

    Member[3] : fc3/1

    iSCSI authentication: None

Removing a Member from a PortChannel

This procedure shows how to remove a member from a PortChannel.

Tip Using the quiesce command allows seamless reduction in the PortChannel, with no dropping of in-flight frames.

This procedure uses the following resources:

Switch 1:

Channel Group 2

Existing Interfaces: fc1/1, fc2/1, fc3/1

Remove Interface: fc3/1

Switch 2:

Channel Group 2

Existing Interfaces: fc1/1, fc2/1, fc3/1

Remove Interface: fc3/1

To remove a member of a PortChannel, follow these steps:

Step 1 On switch 1, quiesce the interfaces to be removed. 

switch1# quiesce interface fc3/1

WARNING: this command will stop forwarding frames to the specified interfaces. I

t is intended to be used to gracefully shutdown interfaces in a port-channel. The

procedure is:

1. quiesce the interfaces on both switches.

2. shutdown the interfaces administratively.

Do you want to continue? (y/n)  [n] y

fc3/1: quiesced

Please quiesce the corresponding interfaces on the other switch and then shut down

them administratively.

Step 2 On switch 2, quiesce the interfaces to be removed. 

switch2# quiesce interface fc3/1

WARNING: this command will stop forwarding frames to the specified interfaces. I

t is intended to be used to gracefully shutdown interfaces in a port-channel. The

procedure is:

1. quiesce the interfaces on both switches.

2. shutdown the interfaces administratively.

Do you want to continue? (y/n)  [n] y

fc3/1: quiesced

Please quiesce the corresponding interfaces on the other switch and then shut down

them administratively.

Step 3 Shut the physical interfaces on both switches.

a. On Switch 1: 

switch1# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch1(config)# int fc3/1

switch1(config-if)# shut

b. On Switch 2: 

switch2# config terminal

Enter configuration commands, one per line.  End with CNTL/Z.

switch2(config)# int fc3/1

switch2(config-if)# shut

Modifying the VSAN Allowed List

Modifying the VSAN allowed list for a PortChannel is the same as modifying it for a standard, single link TE port.

To add VSAN 17 to PortChannel 2, enter these commands: 

switch2# config terminal

switch2(config)# int port-channel 2

switch2(config-if)# switchport trunk allowed vsan add 17

To remove VSAN 17 from PortChannel 2, enter these commands: 

switch2# config terminal

switch2(config)# int port-channel 2

switch2(config-if)# no switchport trunk allowed vsan add 17