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Why does a port show as blocked when the VPIF output shows it's learning and forwarding

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TitleWhy does a port show as blocked when the VPIF output shows it's learning and forwarding
Question
Why does a port show as blocked when the debug vlan show vpif output shows forwarding and learning?
Environment
ALL EXOS
Answer
A port will show as blocked with the Vlan Port Interface (VPIF) output showing "Ingress:0x5, Egress: 0x1" when the port is configured in a LACP LAG, and it has been removed from the aggregator.  A port can be removed from the aggregator for many reasons.  It can be removed because of a data-link communication issue on that link, or the other side of the link is not configured for LACP.  Correct these issues and the port will be come unblocked.

Related troubleshooting articles and reference articles:
How to verify if the LACP PDUs are received from the peer device
How to check ports for possible blocking
 
Additional notes
  1.  The show vlan default command will show you that the port is in a share group, and is blocked.
Switch# show vlan "Default" 
VLAN Interface with name Default created by user
    Admin State:         Enabled     Tagging:   802.1Q Tag 1 
    Description:         None
    Virtual router:      VR-Default
    IPv4 Forwarding:     Disabled
    IPv4 MC Forwarding:  Disabled
    IPv6 Forwarding:     Disabled
    IPv6 MC Forwarding:  Disabled
    IPv6:                None
    STPD:                s0(Disabled,Auto-bind) 
    Protocol:            Match all unfiltered protocols
    Loopback:            Disabled
    NetLogin:            Disabled
    OpenFlow:            Disabled
    QosProfile:          None configured
    Egress Rate Limit Designated Port: None configured
    Flood Rate Limit QosProfile:       None configured
    Ports:   2.           (Number of active ports=2)
       Untag:    *2bg
       Tag:        *1
        Flags:    (*) Active, (!) Disabled, (g) Load Sharing port
                  (b) Port blocked on the vlan, (m) Mac-Based port
                  (a) Egress traffic allowed for NetLogin
                  (u) Egress traffic unallowed for NetLogin
                  (t) Translate VLAN tag for Private-VLAN
                  (s) Private-VLAN System Port, (L) Loopback port
                  (e) Private-VLAN End Point Port
                  (x) VMAN Tag Translated port
                  (G) Multi-switch LAG Group port
                  (H) Dynamically added by MVRP
                  (U) Dynamically added uplink port
                  (V) Dynamically added by VM Tracking
 
  1. The debug vlan show vpif command will show you that port 2 is not in a blocking state. 
Switch# debug vlan show vpif
Process: vlan --- Printing all vpif Start ********************
Total no of vpifs in the system: 2
vlan: Mgmt, port:1:59, instance: 50000001, tag: 0,
        Ingress:0x5, Egress: 0x1, l2 prot priority: 0, cfgSave: TRUE
        l2Protos (id's): 0x0 [pif: linkState:1 phyLinkState:1], uRPF[-]: 0
        clientUsage: 0x0 

vlan: Default, port:1:2, instance: 50000063, tag: 0,
        Ingress:0x5, Egress: 0x1, l2 prot priority: 0, cfgSave: TRUE
        l2Protos (id's): 0x0 [pif: linkState:0 phyLinkState:1], uRPF[-]: 0
        clientUsage: 0x10 


     3.     The show sharing command will show you that the ports have been removed from the aggregator.

Switch# show sharing 
Load Sharing Monitor
Config    Current    Agg       Ld Share    Ld Share  Agg   Link    Link Up
Master    Master     Control   Algorithm   Group     Mbr   State   Transitions
==============================================================================
     2               LACP      L2          2          -      A        1
                               L2          3          -      A        1
==============================================================================
Link State: A-Active, D-Disabled, R-Ready, NP-Port not present, L-Loopback
Load Sharing Algorithm: (L2) Layer 2 address based, (L3) Layer 3 address based
                        (L3_L4) Layer 3 address and Layer 4 port based
                        (custom) User-selected address-based configuration
Custom Algorithm Configuration: ipv4 L3-and-L4, xor
Number of load sharing trunks: 1

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