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Contributor
ggglabs
Posts: 20
Registered: ‎12-15-2011
0

PIM and RPF check problem with BGP route resolved through inet.3 and LSP

Why does PIM not use the BGP route resolved through inet.3 -> LSP as RPF next hop?
Error: Upstream interface: unknown (no nexthop)
BGP protocol next hop is available through IGP also (in inet.0)
If I add static route to source (1.1.1.1/32) pointing at upstream interface (lt-1/2/0.10), multicast starts working.
All interfaces are added to PIM and PIM neighbors are detected.

admin@router# run show pim join logical-system R1 extensive 239.100.100.2
Instance: PIM.master Family: INET
R = Rendezvous Point Tree, S = Sparse, W = Wildcard

Group: 239.100.100.2
    Source: *
    RP: 10.200.90.100
    Flags: sparse,rptree,wildcard
    Upstream interface: Local                 
    Upstream neighbor: Local
    Upstream state: Local RP
    Uptime: 00:33:55
    Downstream neighbors:
        Interface: fe-0/3/0.10            
            192.168.86.1 State: Join Flags: SRW Timeout: 172
            Uptime: 00:33:55 Time since last Join: 00:00:38

Group: 239.100.100.2
    Source: 1.1.1.1
    Flags: sparse
    Upstream interface: unknown (no nexthop)
    Upstream neighbor: unknown
    Upstream state: None, Local RP
    Keepalive timeout: 165
    Uptime: 00:21:31


admin@router# run show multicast rpf 1.1.1.1 logical-system R1
Multicast RPF table: inet.0 , 84 entries

1.1.0.0/16
    Protocol: BGP
    Interface: lt-1/2/0.10


admin@router# run show route 1.1.1.1 logical-system R1

inet.0: 84 destinations, 185 routes (84 active, 0 holddown, 0 hidden)
Restart Complete
+ = Active Route, - = Last Active, * = Both

1.1.0.0/16     *[BGP/170] 1d 03:50:58, localpref 100, from 10.200.90.15
                      AS path: 65530 I
                    > via lt-1/2/0.10, label-switched-path r1-r3
                    [BGP/170] 1d 03:50:50, localpref 100, from 10.200.90.14
                      AS path: 65530 I
                    > via lt-1/2/0.10, label-switched-path r1-r3
                    [BGP/170] 08:31:52, localpref 100, from 10.200.90.16
                      AS path: 65530 I
                    > via lt-1/2/0.10, label-switched-path r1-r3


admin@router# run show pim neighbors logical-system R1
Instance: PIM.master
B = Bidirectional Capable, G = Generation Identifier,
H = Hello Option Holdtime, L = Hello Option LAN Prune Delay,
P = Hello Option DR Priority

Interface           IP V Mode        Option      Uptime Neighbor addr
fe-0/3/0.10          4 2             HPLG      06:56:46 192.168.86.1   
lt-1/2/0.10          4 2             HPLG      06:58:54 192.168.86.20  
lt-1/2/0.12          4 2             HPLG      07:05:02 192.168.86.16  

 

Thank you very much for help

Juniper Employee
jstar
Posts: 22
Registered: ‎04-28-2008
0

Re: PIM and RPF check problem with BGP route resolved through inet.3 and LSP

Junos uses inet.2 for rpf check. Can you check if the route was in inet.2?

Also check if the configuration has lo0.X  added to global and instance level PIM.

Contributor
ggglabs
Posts: 20
Registered: ‎12-15-2011
0

Re: PIM and RPF check problem with BGP route resolved through inet.3 and LSP

[ Edited ]

Hi

 

Thanks for reply.

 

Junos uses inet.0 for rpf check by default. Inet.2 is empty on all routers. This can be verified from my post:

 

admin@router# run show multicast rpf 1.1.1.1 logical-system R1
Multicast RPF table: inet.0 , 84 entries

1.1.0.0/16
    Protocol: BGP
    Interface: lt-1/2/0.10

 

It seems RPF check is unable to use the LSP route. I did a little trick with BGP policy to avoid the LSP route to mcast source (1.1.1.1) and again the multicast started working. This is probably working as it is supposed to, it's just me not understanding why. Or maybe running pim over mpls core is something very stupid from the beginning :smileywink: Luckily this is in the lab...

 

I also checked loopback interface is added to pim.

 

admin@router# run show route 1.1.1.1 logical-system R1

inet.0: 85 destinations, 186 routes (85 active, 0 holddown, 0 hidden)
Restart Complete
+ = Active Route, - = Last Active, * = Both

1.1.0.0/16     *[BGP/170] 00:00:56, localpref 100, from 10.200.90.15
                      AS path: 65530 I
                    > to 192.168.86.20 via lt-1/2/0.10
                    [BGP/170] 00:00:55, localpref 100, from 10.200.90.14
                      AS path: 65530 I
                    > to 192.168.86.20 via lt-1/2/0.10
                    [BGP/170] 00:00:56, localpref 100, from 10.200.90.16
                      AS path: 65530 I
                    > to 192.168.86.20 via lt-1/2/0.10

admin@router# run show pim join logical-system R1 239.100.100.2 extensive
Instance: PIM.master Family: INET
R = Rendezvous Point Tree, S = Sparse, W = Wildcard

Group: 239.100.100.2
    Source: *
    RP: 10.200.90.100
    Flags: sparse,rptree,wildcard
    Upstream interface: Local                 
    Upstream neighbor: Local
    Upstream state: Local RP
    Uptime: 1d 23:52:02
    Downstream neighbors:
        Interface: fe-0/3/0.10            
            192.168.86.1 State: Join Flags: SRW Timeout: 166
            Uptime: 1d 23:52:02 Time since last Join: 00:00:44

Group: 239.100.100.2
    Source: 1.1.1.1
    Flags: sparse
    Upstream interface: lt-1/2/0.10           
    Upstream neighbor: 192.168.86.20
    Upstream state: None, Local RP
    Keepalive timeout: 196
    Uptime: 00:19:02
    Downstream neighbors:
        Interface: fe-0/3/0.10 (pruned)
            192.168.86.1 State: Prune Flags: SR Timeout: 166
            Uptime: 00:03:53 Time since last Prune: 00:00:44


Juniper Employee
jstar
Posts: 22
Registered: ‎04-28-2008
0

Re: PIM and RPF check problem with BGP route resolved through inet.3 and LSP

My Bad...You are correct , it uses inet.0 by default.

 

http://www.juniper.net/techpubs/en_US/junos/topics/topic-map/mcast-rpf.html

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