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This chapter provides information about port tracking and how to configure port tracking.
Your software release might not support all the features documented in this module. For the latest caveats and feature information, see the Bug Search Tool at https://tools.cisco.com/bugsearch/ and the release notes for your software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the New and Changed chapter or the Feature History table below.
Generally, hosts can instantly recover from a link failure on a link that is immediately (direct link) connected to a switch. However, recovering from an indirect link failure between switches in a WAN or MAN fabric with a keep-alive mechanism is dependent on several factors such as the time out values (TOVs) and on registered state change notification (RSCN) information.
In Traffic Recovery Using Port Tracking, when the direct link 1 to the host fails, recovery can be immediate. However, when the ISL 2 fails between the two switches, recovery depends on TOVs, RSCNs, and other factors.
The port tracking feature monitors and detects failures that cause topology changes and brings down the links connecting the attached devices. When you enable this feature and explicitly configure the linked and tracked ports, the Cisco NX-OS software monitors the tracked ports and alters the operational state of the linked ports on detecting a link state change.
The following terms are used in this chapter:
Tracked ports—A port whose operational state is continuously monitored. The operational state of the tracked port is used to alter the operational state of one or more ports. Fibre Channel, VSAN, port channel, FCIP, or a Gigabit Ethernet port can be tracked. Generally, ports in E and TE port modes can also be Fx ports.
Linked ports—A port whose operational state is altered based on the operational state of the tracked ports. Only a Fibre Channel port can be linked.
Before configuring port tracking, consider the following guidelines:
Table 1 lists the default settings for port tracking parameters.
|
Parameters |
Default |
|---|---|
|
Port tracking |
Disabled. |
|
Operational binding |
Enabled along with port tracking. |
Port tracking has the following features:
The application brings the linked port down when the tracked port goes down. When the tracked port recovers from the failure and comes back up again, the tracked port is also brought up automatically (unless otherwise configured).
You can forcefully continue to keep the linked port down, even though the tracked port comes back up. In this case, you must explicitly bring the port up when required.
The port tracking feature is disabled by default in all switches in the Cisco MDS 9000 Series Multilayer Switches. When you enable this feature, port tracking is globally enabled for the entire switch.
To configure port tracking, enable the port tracking feature and configure the linked port(s) for the tracked port.
To enable port tracking, perform these steps:
|
Step 1 |
switch# configure terminal Enters configuration mode. |
|
Step 2 |
switch(config)# feature port-track Enables port tracking. switch(config)# no feature port-track (Optional) Removes the currently applied port tracking configuration and disables port tracking. |
You can link ports using one of two methods:
When you configure the first tracked port, operational binding is automatically in effect. When you use this method, you have the option to monitor multiple ports or monitor ports in one VSAN.
To operationally bind a tracked port, perform these steps:
|
Step 1 |
switch# configure terminal Enters configuration mode. |
||
|
Step 2 |
switch(config)# interface fc8/6 Configures the specified interface and enters the interface configuration submode. You can now configure tracked ports.
|
||
|
Step 3 |
switch(config-if)# port-track interface port-channel 1 Tracks interface fc8/6 with interface port-channel 1. When port-channel 1 goes down, interface fc8/6 is also brought down.
switch(config-if)# no port-track interface port-channel 1 (Optional) Removes the port tracking configuration that is currently applied to interface fc8/6. |
You can control the operational state of the linked port based on the operational states of multiple tracked ports. When more than one tracked port is associated with a linked port, the operational state of the linked port will be set to down only if all the associated tracked ports are down. Even if one tracked port is up, the linked port will stay up.
In Traffic Recovery Using Port Tracking, only if both ISLs 2 and 3 fail, will the direct link 1 be brought down. Direct link 1 will not be brought down if either 2 or 3 are still functioning as desired.
To track multiple ports, perform these steps:
|
Step 1 |
switch# configure terminal Enters configuration mode. |
||
|
Step 2 |
switch(config)# interface fc8/6 Configures the specified interface and enters the interface configuration submode. You can now configure tracked ports.
|
||
|
Step 3 |
switch(config-if)# port-track interface port-channel 1 Tracks interface fc8/6 with interface port-channel 1. When port-channel 1 goes down, interface fc8/6 is also brought down.
|
||
|
Step 4 |
switch(config-if)# port-track interface fcip 5 Tracks interface fc8/6 with interface fcip 5. When FCIP 5 goes down, interface fc8/6 is also brought down.
|
You can optionally configure one VSAN from the set of all operational VSANs on the tracked port with the linked port by specifying the required VSAN. This level of flexibility provides higher granularity in tracked ports. In some cases, when a tracked port is a TE port, the set of operational VSANs on the port can change dynamically without bringing down the operational state of the port. In such cases, the port VSAN of the linked port can be monitored on the set of operational VSANs on the tracked port.
If you configure this feature, the linked port is up only when the VSAN is up on the tracked port.
 Tip |
The specified VSAN does not have to be the same as the port VSAN of the linked port. |
To monitor a tracked port in a specific VSAN, perform these steps:
|
Step 1 |
switch# configure terminal Enters configuration mode. |
|
Step 2 |
switch(config)# interface fc8/6 Configures the specified interface and enters the interface configuration submode. You can now configure tracked ports. |
|
Step 3 |
switch(config-if)# port-track interface port-channel 1 vsan 2 Enables tracking of the port channel in VSAN 2. switch(config-if)# no port-track interface port-channel 1 vsan 2 (Optional) Removes the VSAN association for the linked port. The port channel link remains in effect. |
If a tracked port flaps frequently, then tracking ports using the operational binding feature may cause frequent topology change. In this case, you may choose to keep the port in the down state until you are able to resolve the reason for these frequent flaps. Keeping the flapping port in the down state forces the traffic to flow through the redundant path until the primary tracked port problems are resolved. When the problems are resolved and the tracked port is back up, you can explicitly enable the interface.
Tip |
If you configure this feature, the linked port continues to remain in the shutdown state even after the tracked port comes back up. You must explicitly remove the forced shut state (by administratively bringing up this interface) of the linked port once the tracked port is up and stable. |
To forcefully shut down a tracked port, perform these steps:
|
Step 1 |
switch# configure terminal Enters configuration mode. |
|
Step 2 |
switch(config)# interface fc1/5 Configures the specified interface and enters the interface configuration submode. You can now configure tracked ports. |
|
Step 3 |
switch(config-if)# port-track force-shut Forcefully shuts down the tracked port. switch(config-if)# no port-track force-shut (Optional) Removes the port shutdown configuration for the tracked port. |
The show commands display the current port tracking settings for the Cisco MDS switch (see Examples Displays the Linked and Tracked Port Configuration to Displays a Forced Shutdown Configuration).
switch# show interface
...
fc8/6 is down (All tracked ports down
) <-------------------------------------Linked port
Hardware is Fibre Channel, FCOT is short wave laser
Port WWN is 21:c6:00:05:30:00:37:1e
Admin port mode is auto, trunk mode is on
Port vsan is 1
Receive data field Size is 2112
Beacon is turned off
Port tracked with interface port-channel 1 vsan 2 (trunking) <-----Tracked port
Port tracked with interface fcip 5 <------------------------------------------Tracked port
5 minutes input rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
5 minutes output rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
269946 frames input, 22335204 bytes
0 discards, 0 errors
0 CRC, 0 unknown class
0 too long, 0 too short
205007 frames output, 10250904 bytes
0 discards, 0 errors
0 input OLS, 0 LRR, 0 NOS, 0 loop inits
2 output OLS, 2 LRR, 0 NOS, 1 loop inits
0 receive B2B credit remaining
0 transmit B2B credit remaining
...
switch# show interface fc1/1
fc1/1 is down (Administratively down)
Hardware is Fibre Channel, FCOT is short wave laser w/o OFC (SN)
Port WWN is 20:01:00:05:30:00:0d:de
Admin port mode is FX
Port vsan is 1
Receive data field Size is 2112
Beacon is turned off
Port tracked with interface fc1/2 (down)
Port tracked with interface port-channel 1 vsan 2 (down)
Port tracked with interface fcip1 (down)
5 minutes input rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
5 minutes output rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
1 frames input, 128 bytes
0 discards, 0 errors
0 CRC, 0 unknown class
0 too long, 0 too short
1 frames output, 128 bytes
0 discards, 0 errors
0 input OLS, 0 LRR, 0 NOS, 0 loop inits
0 output OLS, 0 LRR, 0 NOS, 0 loop inits
0 receive B2B credit remaining
0 transmit B2B credit remaining
switch# show interface port-channel 1
port-channel 1 is down (No operational members)
Hardware is Fibre Channel
Port WWN is 24:01:00:05:30:00:0d:de
Admin port mode is auto, trunk mode is on
Port vsan is 2
Linked to 1 port(s)
Port linked to interface fc1/1
5 minutes input rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
5 minutes output rate 0 bits/sec, 0 bytes/sec, 0 frames/sec
0 frames input, 0 bytes
0 discards, 0 errors
0 CRC, 0 unknown class
0 too long, 0 too short
0 frames output, 0 bytes
0 discards, 0 errors
0 input OLS, 0 LRR, 0 NOS, 0 loop inits
0 output OLS, 0 LRR, 0 NOS, 0 loop inits
No members
switch# show interface fc 1/5
fc1/5 is up
Hardware is Fibre Channel, FCOT is short wave laser
Port WWN is 20:05:00:05:30:00:47:9e
Admin port mode is F
Port mode is F, FCID is 0x710005
Port vsan is 1
Speed is 1 Gbps
Transmit B2B Credit is 64
Receive B2B Credit is 16
Receive data field Size is 2112
Beacon is turned off
Port track mode is force_shut <--this port remains shut even if the tracked port is back up
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