[j-nsp] M Series BGP path selection

David Gethings davidg at pipex.net
Wed Oct 6 06:51:42 EDT 2004


Hi All,

Attached is the output of the command 'show route 81.89.128.0/20 extentsive'. 
As I understand the BGP path selection path 4 (next hop 146.188.68.233) 
should be chosen. However it is not.

Could someone please explain why.

Cheers

Dg
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inet.0: 149862 destinations, 860842 routes (149857 active, 5 holddown, 0 hidden)
Restart Complete
81.89.128.0/20 (6 entries, 1 announced)
TSI:
KRT in-kernel 81.89.128.0/20 -> {indirect(416), indirect(467)}
Standby generator for 0.0.0.0/0
Page 0 idx 1 Type 1 val 1750ff78
    Nexthop: Self
    Localpref: 100
    AS path: 1299 3356 25022 I
    Communities: 25346:130
Path 81.89.128.0 from 213.248.100.41 Vector len 4.  Val: 1
        *BGP    Preference: 170/-101
                Source: 213.248.100.41
                Next hop: 213.248.100.41 via ge-2/1/0.0, selected
                Next hop: 213.248.100.105 via ge-3/1/0.0
                Protocol next hop: 213.248.100.41 Indirect next hop: 87a8900 416
                Protocol next hop: 213.248.100.105 Indirect next hop: 87a89c0 467
                State: <Active Ext>
                Local AS: 25346 Peer AS:  1299
                Age: 5d 12:57:06 	Metric2: 0 
                Task: BGP_1299.213.248.100.41+179
                Announcement bits (5): 0-KRT 1-RT 4-Aggregate 5-BGP.0.0.0.0+179 6-Resolve inet.0 
                AS path: 1299 3356 25022 I
                Communities: 25346:130
                Localpref: 100
                Router ID: 213.248.75.253
                Indirect next hops: 2
                        Protocol next hop: 213.248.100.41 Indirect next hop: 87a8900 416
                        Indirect path forwarding next hops: 1
                                Next hop: 213.248.100.41 via ge-2/1/0.0
			213.248.100.40/30 Originating RIB: inet.0
			  Node path count: 1
			  Forwarding nexthops: 1
				Next hop type: Interface
				Nexthop: via ge-2/1/0.0
                        Protocol next hop: 213.248.100.105 Indirect next hop: 87a89c0 467
                        Indirect path forwarding next hops: 1
                                Next hop: 213.248.100.105 via ge-3/1/0.0
			213.248.100.104/30 Originating RIB: inet.0
			  Node path count: 1
			  Forwarding nexthops: 1
				Next hop type: Interface
				Nexthop: via ge-3/1/0.0
         BGP    Preference: 170/-101
                Source: 213.248.100.105
                Next hop: 213.248.100.105 via ge-3/1/0.0, selected
                Protocol next hop: 213.248.100.105 Indirect next hop: 87a89c0 467
                State: <NotBest Ext>
                Inactive reason: Update source
                Local AS: 25346 Peer AS:  1299
                Age: 5d 12:57:06 	Metric2: 0 
                Task: BGP_1299.213.248.100.105+179
                AS path: 1299 3356 25022 I
                Communities: 25346:130
                Localpref: 100
                Router ID: 213.248.75.253
                Indirect next hops: 1
                        Protocol next hop: 213.248.100.105 Indirect next hop: 87a89c0 467
                        Indirect path forwarding next hops: 1
                                Next hop: 213.248.100.105 via ge-3/1/0.0
			213.248.100.104/30 Originating RIB: inet.0
			  Node path count: 1
			  Forwarding nexthops: 1
				Next hop type: Interface
				Nexthop: via ge-3/1/0.0
         BGP    Preference: 170/-101
                Source: 62.241.161.243
                Next hop: 62.241.161.130 via ge-1/1/0.5, selected
                Protocol next hop: 62.241.161.243 Indirect next hop: 87a8300 321
                State: <NotBest Int Ext>
                Inactive reason: Interior > Exterior > Exterior via Interior
                Local AS: 25346 Peer AS: 25346
                Age: 5d 12:57:08 	Metric2: 5 
                Task: BGP_25346.62.241.161.243+4690
                AS path: 1299 3356 25022 I
                Communities: 25346:130
                Localpref: 100
                Router ID: 62.241.161.243
                Indirect next hops: 1
                        Protocol next hop: 62.241.161.243 Metric: 5 Indirect next hop: 87a8300 321
                        Indirect path forwarding next hops: 1
                                Next hop: 62.241.161.130 via ge-1/1/0.5
			62.241.161.243/32 Originating RIB: inet.0
			  Metric: 5			  Node path count: 1
			  Forwarding nexthops: 1
				Nexthop: 62.241.161.130 via ge-1/1/0.5
         BGP    Preference: 170/-101
                Source: 146.188.68.233
                Next hop: 146.188.68.233 via ge-0/2/0.0, selected
                Protocol next hop: 146.188.68.233 Indirect next hop: 87a8600 323
                State: <Ext>
                Inactive reason: Active preferred
                Local AS: 25346 Peer AS:   702
                Age: 5d 12:56:35 	Metric2: 0 
                Task: BGP_702.146.188.68.233+21065
                AS path: 702 3356 25022 I
                Communities: 25346:120
                Localpref: 100
                Router ID: 158.43.234.11
                Indirect next hops: 1
                        Protocol next hop: 146.188.68.233 Indirect next hop: 87a8600 323
                        Indirect path forwarding next hops: 1
                                Next hop: 146.188.68.233 via ge-0/2/0.0
			146.188.68.232/30 Originating RIB: inet.0
			  Node path count: 1
			  Forwarding nexthops: 1
				Next hop type: Interface
				Nexthop: via ge-0/2/0.0
         BGP    Preference: 170/-101
                Source: 146.188.53.221
                Next hop: 146.188.53.221 via ge-3/0/0.0, selected
                Protocol next hop: 146.188.53.221 Indirect next hop: 87a8000 382
                State: <NotBest Ext>
                Inactive reason: Not Best in its group
                Local AS: 25346 Peer AS:   702
                Age: 5d 12:56:48 	Metric2: 0 
                Task: BGP_702.146.188.53.221+21366
                AS path: 702 3356 25022 I
                Communities: 25346:120
                Localpref: 100
                Router ID: 158.43.234.21
                Indirect next hops: 1
                        Protocol next hop: 146.188.53.221 Indirect next hop: 87a8000 382
                        Indirect path forwarding next hops: 1
                                Next hop: 146.188.53.221 via ge-3/0/0.0
			146.188.53.220/30 Originating RIB: inet.0
			  Node path count: 1
			  Forwarding nexthops: 1
				Next hop type: Interface
				Nexthop: via ge-3/0/0.0
         BGP    Preference: 170/-101
                Source: 62.241.161.252
                Next hop: 62.241.161.130 via ge-1/1/0.5, selected
                Next hop: 62.241.161.98 via ge-1/2/0.0
                Protocol next hop: 62.241.161.252 Indirect next hop: 87a8480 452
                State: <NotBest Int Ext>
                Inactive reason: Not Best in its group
                Local AS: 25346 Peer AS: 25346
                Age: 5d 12:56:50 	Metric: 0 	Metric2: 11 
                Task: BGP_25346.62.241.161.252+65365
                AS path: 702 3356 25022 I
                Communities: 25346:120
                Localpref: 100
                Router ID: 62.241.161.252
                Indirect next hops: 1
                        Protocol next hop: 62.241.161.252 Metric: 11 Indirect next hop: 87a8480 452
                        Indirect path forwarding next hops: 2
                                Next hop: 62.241.161.130 via ge-1/1/0.5
                                Next hop: 62.241.161.98 via ge-1/2/0.0
			62.241.161.252/32 Originating RIB: inet.0
			  Metric: 11			  Node path count: 1
			  Forwarding nexthops: 2
				Nexthop: 62.241.161.130 via ge-1/1/0.5
				Nexthop: 62.241.161.98 via ge-1/2/0.0


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