Configuring and Managing AVB

AVB is not enabled in the default configuration, and must be enabled both globally on the switch and on the ports where you want to use it. In the simplest case, when starting with a blank configuration, AVB may be enabled by executing the following two commands:

# enable avb

enable avb ports all

The status of AVB can be seen by using the following command:

# show avb   
gPTP status         : Enabled   
gPTP enabled ports  : *1s     *2m    *10m    *11m    *12m                            
                     *13m    *14m    *15m    *16m    *17m                            
                     *18m    *19m    *20m    *21m           

MSRP status         : Enabled   
MSRP enabled ports  : *1ab    *2ab   *10ab   *11ab   *12ab                           
                     *13ab   *14ab   *15ab   *16ab   *17ab                           
                     *18ab   *19ab   *20ab   *21ab          

MVRP status         : Enabled   
MVRP enabled ports  : *1      *2     *10     *11     *12                             
                     *13     *14     *15     *16     *17    
                     *18     *19     *20     *21            

Flags:        (*) Active,                  (!) Administratively disabled,                 
              (a) SR Class A allowed,      (b) SR Class B allowed,                  
              (d) Disabled gPTP port role, (m) Master gPTP port role,                 
              (p) Passive gPTP port role,  (s) Slave gPTP port role    

The show avb command displays high level information about each of the three main protocols (gPTP, MSRP, and MVRP). Each protocol section indicates that all three protocols are enabled both globally, and on ports 1,2 and 11-21. The “*” indicates that we have link on each of the ports.

The gPTP status indicates that port 1 is a slave port, which means that the Grand Master Clock (GMC) is reachable through port 1. The gPTP status also indicates that the rest of the ports are master ports. Furthermore, the fact that no ports are shown to be in the Disabled role means that gPTP is operational on all the ports.

ExtremeXOS provides static AVB configuration with the exception of of Best Master Clock Algorithm (BMCA), which runs as part of gPTP. The BMCA feature adds the ability to disable BMCA and to specify a slave port if desired. When BMCA functionality is on, BMCA is executed normally as described in IEEE 802.1AS. When BMCA is off, BMCA is not executed. In disabled mode, a port can be configured to be the slave-port. If no ports are configured to be slave-port, then the switch will become the Grandmaster Clock and all network-gptp enabled ports will be master ports. The show network-gptp command displays whether BMCA is on or off.

The "ab" on the MSRP status indicates that all ports are members of both the class A and class B domain domains. The MVRP status simply shows which ports are enabled and active.

The user interface for AVB includes the following five protocols:

• gPTP
• MRP
• MVRP
• MSRP
• FQTSS

The "avb" commands shown above are part of a set of AVB macro commands provided to simplify the process of enabling and disabling AVB. The AVB macro commands have the form:

[ enable | disable | unconfigure ] avb { ports [ all | port_list ] }

Using one of the macro commands is the same as executing the following three commands:

[ enable | disable | unconfigure ] network-clock gptp { ports [ all | port_list ]}

[ enable | disable | unconfigure ] mvrp { ports [ all | port_list ]}

[ enable | disable | unconfigure ] msrp { ports [ all | port_list ]}

MRP does not need to be enabled or disabled, and the only MRP properties that may be configured are timer values. The defaults should be sufficient for most deployments, though it may be necessary to increase the leave-all and leave time values when supporting a large number of streams.

Multiple Registration Protocol/Multiple VLAN Registration Protocol is used for dynamically creating VLANs and/or dynamically adding ports to VLANs. As per IEEE Std 802.1Q-2011, some VLANs can be marked as forbidden VLANs on some ports so that when MVRP PDU is received on the port with the particular forbidden VLAN Id, the VLAN is not created and if the VLAN is already there, the port is not added to the VLAN. This functionality was added in 15.3.2.

MVRP data structure is based on port Instance. All dynamic VLANs created or propagated for a given port will be stored for each port Instance. For normal ports, the port Instance will correspond to the PIF port instance, and for LAG ports, the port Instance will correspond to the LIF port Instance. The port instance is not shown in any of the standard CLI show commands, though it is available as a part of the debug commands. Once MVRP is enabled on the master port, addition / deletion of individual links is supported. MVRP packets received on the newly added link will be accounted instantaneously.