def describe_virtual_interfaces(connectionId=None, virtualInterfaceId=None):
    """
    Displays all virtual interfaces for an AWS account. Virtual interfaces deleted fewer than 15 minutes before you make the request are also returned. If you specify a connection ID, only the virtual interfaces associated with the connection are returned. If you specify a virtual interface ID, then only a single virtual interface is returned.
    A virtual interface (VLAN) transmits the traffic between the AWS Direct Connect location and the customer.
    See also: AWS API Documentation
    
    
    :example: response = client.describe_virtual_interfaces(
        connectionId='string',
        virtualInterfaceId='string'
    )
    
    
    :type connectionId: string
    :param connectionId: The ID of the connection. This field is also used as the ID type for operations that use multiple connection types (LAG, interconnect, and/or connection).
            Example: dxcon-fg5678gh
            Default: None
            

    :type virtualInterfaceId: string
    :param virtualInterfaceId: The ID of the virtual interface.
            Example: dxvif-123dfg56
            Default: None
            

    :rtype: dict
    :return: {
        'virtualInterfaces': [
            {
                'ownerAccount': 'string',
                'virtualInterfaceId': 'string',
                'location': 'string',
                'connectionId': 'string',
                'virtualInterfaceType': 'string',
                'virtualInterfaceName': 'string',
                'vlan': 123,
                'asn': 123,
                'authKey': 'string',
                'amazonAddress': 'string',
                'customerAddress': 'string',
                'addressFamily': 'ipv4'|'ipv6',
                'virtualInterfaceState': 'confirming'|'verifying'|'pending'|'available'|'down'|'deleting'|'deleted'|'rejected',
                'customerRouterConfig': 'string',
                'virtualGatewayId': 'string',
                'routeFilterPrefixes': [
                    {
                        'cidr': 'string'
                    },
                ],
                'bgpPeers': [
                    {
                        'asn': 123,
                        'authKey': 'string',
                        'addressFamily': 'ipv4'|'ipv6',
                        'amazonAddress': 'string',
                        'customerAddress': 'string',
                        'bgpPeerState': 'verifying'|'pending'|'available'|'deleting'|'deleted',
                        'bgpStatus': 'up'|'down'
                    },
                ]
            },
        ]
    }
    
    
    :returns: 
    ipv4 : IPv4 address family
    ipv6 : IPv6 address family
    
    """
    pass
