tll-rs1/ipv4: show protocols all ulan

ulan BGP --- start 2021-08-23 Idle Error: Link down

Description:    ulan/48128/AS48128/via IPTP
  BGP state:          Idle
    Neighbor address: 37.9.49.72
    Neighbor AS:      48128
    Local AS:         57936
    Last error:       Error: Link down
  Channel ipv4
    State:          DOWN
    Table:          master4
    Preference:     100
    Input filter:   (unnamed)
    Output filter:  (unnamed)
    Import limit:   5000
      Action:       disable