[BGPCEP-909] Algo Path Computation - Bandwidth constraint computation and class-type

Tue, 12 Jan 2021 10:23:22 +0000

Hello,

context : I use Opendaylight with CSR1000v and BGP-LS protocol for link state topology. my network is configured to use TE class, and for clear understanding with the example below, I have the following TE-class mapping :

TE-Class Class-Type Priority
 0             0                7
 1             0                6
 2             0                4
 3             0                1
 4             1                7
 5             1                4
 6             1                2
 7             1                1

The problem is the class-type of the path computation request is not matched with class-type of edge attributes, but matched with the list index of unreserved bandwitdh from edge attributes. it's not the same.

AbstractPathComputation line 230 :

(attributes.getUnreservedBandwidth().get(constraints.getClassType().intValue()).getBandwidth().getValue().longValue() < bandwidth)

Below an example with one edge and bandwidth contraints (I have hidden id and ip for security reasons) and the various results gathered using path computation request.

{
	"edge-id": xxxxxxxxx,
	"remote-vertex-id": yyyyyyyyy,
	"local-vertex-id": xxxxxxxxx,
	"name": "xxxxxxxxx - yyyyyyyyy",
	"edge-attributes": {
		"metric": 1,
		"max-resv-link-bandwidth": 1000000,
		"remote-address": "x.x.x.x",
		"local-address": "x.x.x.x",
		"admin-group": 4,
		"unreserved-bandwidth": [
			{
				"class-type": 7,
				"bandwidth": 200000
			},
			{
				"class-type": 6,
				"bandwidth": 200000
			},
			{
				"class-type": 5,
				"bandwidth": 75000
			},
			{
				"class-type": 4,
				"bandwidth": 75000
			},
			{
				"class-type": 3,
				"bandwidth": 1000000
			},
			{
				"class-type": 2,
				"bandwidth": 875000
			},
			{
				"class-type": 1,
				"bandwidth": 875000
			},
			{
				"class-type": 0,
				"bandwidth": 875000
			}
		],
		"max-link-bandwidth": 1000000,
		"te-metric": 1
	}
}

cisco topology on this edge :

    BC Model Id: RDM
      BC0 (max_reservable): 8000 (kbps)
      BC0 (max_reservable_bw_global): 8000 (kbps)
      BC1 (max_reservable_bw_sub): 1600 (kbps)

               Total Allocated   Reservable
               BW (kbps)         BW (kbps)
               ---------------   -----------
    TE-Class[0]:         1000             7000
    TE-Class[1]:         1000             7000
    TE-Class[2]:         1000             7000
    TE-Class[3]:            0             8000
    TE-Class[4]:         1000              600
    TE-Class[5]:         1000              600
    TE-Class[6]:            0             1600
    TE-Class[7]:            0             1600

tests and results with computation request :

{"input":{"algorithm":"cspf","constraints":{"address-family":"ipv4","bandwidth":200000,"class-type":0},"destination":AAAAAA,"graph-name":"ted://netip-bgp-linkstate-topology","source":BBBBBBB}} 
=> Ero contains yyyyyyyyy 

{"input":{"algorithm":"cspf","constraints":{"address-family":"ipv4","bandwidth":210000,"class-type":0},"destination":AAAAAA,"graph-name":"ted://netip-bgp-linkstate-topology","source":BBBBBBB}} 
=> I have another ero without yyyyyyyyy

in this result, classtype 0 in resquest correspond to class type 7 from the edge.

{"input":{"algorithm":"cspf","constraints":{"address-family":"ipv4","bandwidth":75000,"class-type":3},"destination":AAAAAA,"graph-name":"ted://netip-bgp-linkstate-topology","source":BBBBBBB}} 
=> Ero contains yyyyyyyyy 

{"input":{"algorithm":"cspf","constraints":{"address-family":"ipv4","bandwidth":80000,"class-type":3},"destination":AAAAAA,"graph-name":"ted://netip-bgp-linkstate-topology","source":BBBBBBB}} 
=> I have another ero without yyyyyyyyy

=> above, class type 3 in path computation request correspond to class type 4 from edge unreserved bandwidth attributes.

another example :

{"input":{"algorithm":"cspf","constraints":{"address-family":"ipv4","bandwidth":1000000,"class-type":4},"destination":AAAAAA,"graph-name":"ted://netip-bgp-linkstate-topology","source":BBBBBBB}} => Ero contains yyyyyyyyy

best regards

Jean-Marc

OpenDaylight JIRA

[BGPCEP-909] Algo Path Computation - Bandwidth constraint computation and class-type