CREATE TABLE [dbo].[links](
	[link_id] [int] IDENTITY(1,1) NOT NULL,
	[node1_id] [int] NOT NULL,
	[node2_id] [int] NOT NULL,
	[weight] [int] NULL,
	[id_min]  AS (case when [node1_id]<[node2_id] then [node1_id] else [node2_id] end),
	[id_max]  AS (case when [node1_id]>[node2_id] then [node1_id] else [node2_id] end),
	[descr] [nvarchar](max) NULL,
PRIMARY KEY CLUSTERED 
(
	[link_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY],
UNIQUE NONCLUSTERED 
(
	[id_min] ASC,
	[id_max] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]


insert into dbo.links
		 (node1_id, node2_id, weight, descr)
SELECT * 
FROM (
VALUES 
(1,6,14,NULL),
(1,3,9,NULL),
(1,2,7,NULL),
(6,5,9,NULL),
(6,3,2,NULL),
(3,4,11,NULL),
(3,2,10,NULL),
(2,4,15,NULL),
(4,5,6,NULL)) AS vtable 
([node1_id],[node2_id],[weight],[descr])

declare
   @step_id int = 2
  ,@max_recurtion int = 10
  ,@first_node int = 1
  ,@last_node int = 5


declare	@t table (
	deep int
   ,node1_id int
   ,node2_id int
   ,[root] nvarchar(max)
   ,[weight] int
   ,first_node int
   ,last_node as (case when charindex(',', [root]) > 0
					   then cast(substring(reverse([root]), 0, charindex(',', [root])) as integer)
					   else 0
				  end)
   )

insert	 into @t
		 (
		  deep
		 ,node1_id
		 ,node2_id
		 ,[root]
		 ,[weight]
		 ,first_node
		 )
		 select
			1
		   ,node1_id
		   ,node2_id
		   ,cast(node1_id as nvarchar(8)) + ',' + cast(node2_id as nvarchar(8))
		   ,l.[weight]
		   ,l.node1_id
		 from
			links l


while @step_id < @max_recurtion 
   begin 

	  insert   into @t
			   (
				deep
			   ,node1_id
			   ,node2_id
			   ,[root]
			   ,[weight]
			   ,first_node
			   )
			   select
				  @step_id
				 ,t.node2_id
				 ,l.node2_id
				 ,t.[root] + ',' + cast(l.node2_id as nvarchar(8))
				 ,t.[weight] + l.[weight]
				 ,t.first_node
			   from
				  @t t
				  inner join links l
					 on t.node2_id = l.node1_id
						and l.node2_id <> t.node1_id
			   where
				  t.deep = @step_id - 1

	  if @@rowcount = 0 
		 break;

	  set @step_id = @step_id + 1
   end

select
   *
from
   @t t
where t.first_node = @first_node and t.last_node = @last_node
or t.first_node = @last_node and  t.last_node = @first_node