Example: Configuring Two or More Lossless FCoE Priorities on the Same FCoE Transit Switch Interface

Requirements

• One Juniper Networks QFX3500 Switch in transit switch (FIP snooping) mode
• Junos OS Release 12.3 or later for the QFX Series

Overview

Some network topologies support FCoE traffic on more than one IEEE 802.1p priority. For example, a converged Ethernet network might include two separate FCoE networks that use different priorities to identify traffic. Interfaces that carry traffic for both FCoE networks need to support lossless FCoE transport on both priorities.

Supporting lossless behavior for two FCoE traffic classes requires configuring:

• At least one lossless forwarding class for FCoE traffic (this example uses the default fcoe forwarding class as one of the lossless FCoE forwarding classes, so we need to explicitly configure only one FCoE forwarding class).
• A behavior aggregate (BA) classifier to map the FCoE forwarding classes to the appropriate IEEE 802.1p code points (priorities).
• A congestion notification profile (CNP) to enable PFC on the FCoE code points at the interface ingress and to configure PFC flow control on the interface egress so that the interface can respond to PFC messages received from the connected peer.
• DCBX applications and an application map to support DCBX application TLV exchange for the lossless FCoE traffic on the configured FCoE priorities. By default, DCBX is enabled on all Ethernet interfaces, but only on priority 3 (IEEE 802.1p code point 011). To support DCBX application TLV exchange when you are not using the default configuration, you must configure all of the applications and map them to interfaces and priorities.

The priorities specified in the BA classifier, CNP, and DCBX application map must match, or the configuration does not work. You must specify the same lossless FCoE forwarding class in each configuration and use the same IEEE 802.1p code point (priority) so that the FCoE traffic is properly classified into flows and so that those flows receive lossless treatment.

Topology

This example shows how to configure two lossless FCoE traffic classes on an interface, map them to two different priorities, and configure flow control to ensure lossless behavior. This example uses two Ethernet interfaces, xe-0/0/20 and xe-0/0/21, that are connected to the converged Ethernet network. Both interfaces transport FCoE traffic on priorities 3 (011) and 5 (101), and must support lossless transport of that traffic.

Table 1 shows the configuration components for this example.

Note: This example does not include scheduling (bandwidth allocation) configuration or the FIP snooping configuration. This examples focuses only on the lossless FCoE priority configuration.

Configuration

CLI Quick Configuration

To quickly configure two lossless FCoE forwarding classes that use different priorities on an FCoE transit switch interface, copy the following commands, paste them in a text file, remove line breaks, change variables and details to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.

Step-by-Step Procedure

1. Configure lossless forwarding class fcoe1 and map it to output queue 5 for FCoE traffic that uses IEEE 802.1p priority 5:
   [edit class-of-service]
user@switch# set forwarding-classes class fcoe1 queue-num 5 no-loss

   Note: This examples uses the default fcoe forwarding class as the other lossless FCoE forwarding class.

   
   

2. Configure the ingress classifier. The classifier maps the FCoE priorities (IEEE 802.1p code points 011 and 101) to lossless FCoE forwarding classes fcoe and fcoe1, respectively:
   [edit class-of-service classifiers]
user@switch# set ieee-802.1 fcoe_classifier forwarding-class fcoe loss-priority low code-points 011
user@switch# set ieee-802.1 fcoe_classifier forwarding-class fcoe1 loss-priority low code-points 101

   
   

3. Apply the classifier to the interfaces:
   [edit class-of-service]
user@switch# set interfaces xe-0/0/20 unit 0 classifiers ieee-802.1 fcoe_classifier
user@switch# set interfaces xe-0/0/21 unit 0 classifiers ieee-802.1 fcoe_classifier

   
   

4. Configure the CNP. The input stanza enables PFC on the FCoE priorities (IEEE 802.1p code points 011 and 101), sets the MRU value (2240 bytes), and sets the cable length value (100 meters). The output stanza configures flow control on output queues 3 and 5 on the FCoE priorities:
   [edit class-of-service]
user@switch# set congestion-notification-profile fcoe_cnp input ieee-802.1 code-point 011 pfc mru 2240
user@switch# set congestion-notification-profile fcoe_cnp input ieee-802.1 code-point 101 pfc mru 2240
user@switch# set congestion-notification-profile fcoe_cnp input cable-length 100
user@switch# set congestion-notification-profile fcoe_cnp output ieee-802.1 code-point 011 pfc flow-control-queue 3
user@switch# set congestion-notification-profile fcoe_cnp output ieee-802.1 code-point 101 pfc flow-control-queue 5

   
   

5. Apply the CNP to the interfaces:
   [edit class-of-service]
user@switch# set interfaces xe-0/0/20 congestion-notification-profile fcoe_cnp
user@switch# set interfaces xe-0/0/21 congestion-notification-profile fcoe_cnp

   
   

6. Configure a DCBX application for FCoE to map to the Ethernet interfaces, so that DCBX can exchange application protocol TLVs on both of the IEEE 802.1p priorities used for FCoE transport:
   [edit]
user@switch# set applications application fcoe_app ether-type 0x8906

   
   

7. Configure a DCBX application map to map the FCoE application to the correct IEEE 802.1p FCoE priorities:
   [edit]
user@switch# set policy-options application-maps fcoe_app_map application fcoe_app code-points [011 101]

   
   

8. Apply the application map to the interfaces so that DCBX exchanges FCoE application TLVs on the correct code points:
   [edit]
user@switch# set protocols dcbx interface xe-0/0/20 application-map fcoe_app_map
user@switch# set protocols dcbx interface xe-0/0/21 application-map fcoe_app_map

   
   

Verification

To verify the configuration and proper operation of the lossless forwarding classes and IEEE 802.1p priorities, perform these tasks:

• Verifying the Forwarding Class Configuration
• Verifying the Behavior Aggregate Classifier Configuration
• Verifying the PFC Flow Control Configuration (CNP)
• Verifying the Interface Configuration
• Verifying the DCBX Application Configuration
• Verifying the DCBX Application Map Configuration
• Verifying the DCBX Application Protocol Exchange Interface Configuration

Verifying the Forwarding Class Configuration

Purpose

Verify that the lossless forwarding class fcoe1 has been created.

Action

Forwarding class                       ID      Queue  Policing priority  No-Loss
  best-effort                          0         0         normal        Disabled
  fcoe                                 1         3         normal        Enabled
  no-loss                              2         4         normal        Enabled
  network-control                      3         7         normal        Disabled
  fcoe1                                4         5         normal        Enabled
  mcast                                8         8         normal        Disabled

Meaning

The show class-of-service forwarding-class command shows all of the forwarding classes. The command output shows that the fcoe1 forwarding class is configured on output queue 5 with the no-loss packet drop attribute enabled.

Because we did not explicitly configure the default forwarding classes, they remain in their default state, including the lossless configuration of the fcoe and no-loss default forwarding classes.

Verifying the Behavior Aggregate Classifier Configuration

Purpose

Verify that the three classifiers map the forwarding classes to the correct IEEE 802.1p code points (priorities) and packet loss priorities.

Action

List the classifiers using the operational mode command show class-of-service classifier:

Classifier: fcoe_classifier, Code point type: ieee-802.1, Index: 10964
  Code point         Forwarding class                    Loss priority
  011                fcoe                                low         
  101                fcoe1                               low         

Meaning

The show class-of-service classifier command shows the IEEE 802.1p code points and the loss priorities that are mapped to the forwarding classes in each classifier.

Classifier fcoe_classifier maps code point 011 to default lossless forwarding class fcoe and a packet loss priority of low, and maps code point 101 to explicitly configured lossless forwarding class fcoe1 and a packet loss priority of low.

Verifying the PFC Flow Control Configuration (CNP)

Purpose

Verify that PFC is enabled on the correct input priorities and that flow control is configured on the correct output queues and priorities.

Action

List the CNPs using the operational mode command show class-of-service congestion-notification:

Name: fcoe_cnp, Index: 46504
Type: Input
Cable Length: 100 m
  Priority     PFC          MRU
  000          Disabled 
  001          Disabled 
  010          Disabled 
  011          Enabled      2240 
  100          Disabled 
  101          Enabled      2240 
  110          Disabled 
  111          Disabled 
Type: Output
  Priority     Flow-Control-Queues      
  011 
               3
  101 
               5

Meaning

The show class-of-service congestion-notification command shows the input and output stanzas of the CNP.

The CNP fcoe_cnp input stanza shows that PFC is enabled on code points 011 and 101, the MRU is 2240 bytes on both priorities, and the interface cable length is 100 meters. The CNP output stanza shows that output flow control is configured on queues 3 and 5 for code points 011 and 101, respectively.

Verifying the Interface Configuration

Purpose

Verify that the classifier and congestion notification profile are configured on the interfaces. Both interfaces should show the same configuration.

Action

List the ingress interfaces using the operational mode commands show configuration class-of-service interfaces xe-0/0/20 and show configuration class-of-service interfaces xe-0/0/21:

ccongestion-notification-profile fcoe_cnp;
unit 0 {
    classifiers {
        ieee-802.1 fcoe_classifier;
    }
}

congestion-notification-profile fcoe_cnp;
unit 0 {
    classifiers {
        ieee-802.1 fcoe_classifier;
    }
}

Meaning

The show configuration class-of-service interfaces xe-0/0/20 command shows that the congestion notification profile fcoe_cnp is configured on the interface, and that the IEEE 802.1p classifier associated with the interface is fcoe_classifier.

The show configuration class-of-service interfaces xe-0/0/21 command shows that the congestion notification profile fcoe_cnp is configured on the interface, and that the IEEE 802.1p classifier associated with the interface is fcoe_classifier.

Verifying the DCBX Application Configuration

Purpose

Verify that the DCBX application for FCoE is configured.

Action

List the DCBX applications by using the configuration mode command show applications:

application fcoe_app {
    ether-type 0x8906;

Meaning

The show applications configuration mode command shows all of the configured applications. The output shows that the application fcoe_app is configured with an EtherType of 0x8906.

Verifying the DCBX Application Map Configuration

Purpose

Verify that the application map is configured.

Action

List the application maps by using the configuration mode command show policy-options application-maps:

fcoe_app_map {
    application fcoe_app code-points [011 101];
}

Meaning

The show policy-options application-maps configuration mode command lists all of the configured application maps and the applications that belong to each application map. The output shows that application map fcoe_app_map consists of the application named fcoe_app, which is mapped to IEEE 802.1p code points 011 and 101 (priorities 3 and 5, respectively).

Verifying the DCBX Application Protocol Exchange Interface Configuration

Purpose

Verify that the application map is applied to the interfaces.

Action

List the application maps on each interface using the configuration mode command show protocols dcbx:

interface xe-0/0/20.0 {
    application-map fcoe_app_map;
}
interface xe-0/0/21.0 {
    application-map fcoe_app_map;
}

Meaning

The show protocols dcbx configuration mode command lists the application map association with interfaces. The output shows that interfaces xe-0/0/20.0 and xe-0/0/21.0 use application map fcoe_app_map.