Examine BGP Routes
Purpose
You can examine the BGP path selection process to determine the single, active path when BGP receives multiple routes to the same destination. In this step, we examine the reverse LSP R6-to-R1, making R6 the ingress router for that LSP.
Action
To examine BGP routes and route selection, enter the following Junos OS CLI operational mode command:
Sample Output 1
user@R6> show route 100.100.1.1 detail inet.0: 30 destinations, 46 routes (29 active, 0 holddown, 1 hidden)
100.100.1.0/24 (1 entry, 1 announced)
*BGP Preference: 170/-101
Source: 10.1.13.1
Next hop: via so-0/0/3.0, selected
Protocol next hop: 10.1.13.1 Indirect next hop: 8671594 304
State: <Active Int Ext>
Local AS: 65432 Peer AS: 65432
Age: 4d 5:15:39 Metric2: 2
Task: BGP_65432.10.1.13.1+3048
Announcement bits (2): 0-KRT 4-Resolve inet.0
AS path: I
Localpref: 100
Router ID: 10.0.0.1
Sample Output 2
user@R6> show route 100.100.1.1 detail inet.0: 30 destinations, 46 routes (29 active, 0 holddown, 1 hidden)
100.100.1.0/24 (1 entry, 1 announced)
*BGP Preference: 170/-101
Source: 10.0.0.1
Next hop: via so-0/0/3.0 weight 1, selected
Label-switched-path R6-to-R1
Label operation: Push 100000
Protocol next hop: 10.0.0.1 Indirect next hop: 8671330 301
State: <Active Int Ext>
Local AS: 65432 Peer AS: 65432
Age: 24:35 Metric2: 2
Task: BGP_65432.10.0.0.1+179
Announcement bits (2): 0-KRT 4-Resolve inet.0
AS path: I
Localpref: 100
Router ID: 10.0.0.1
Meaning
Sample Output 1 shows that the BGP next hop (10.1.13.1) does not equal the LSP destination address (10.0.0.1) in the to statement at the [edit protocols mpls label-switched-path label-switched-path-name] hierarchy level when the BGP configuration of R6 and R1 is incorrect.
Sample Output 2, taken after the configurations on R1 and R6 are corrected, shows that the BGP next hop (10.0.0.1) and the LSP destination address (10.0.0.1) are the same, indicating that BGP can use the LSP to forward BGP traffic.
