[Xorp-users] two BSRs

[Pavlin Radoslavov]

Pavlin Radoslavov <pavlin at ICSI.Berkeley.EDU> wrote:

> Mikael Johansson <johansson500 at gmail.com> wrote:
> 
> > I am trying to configure two BSRs so that one router is BSR for some
> > multicast groups and another router is BSR for different multicast
> > groups.
> > 
> > Routers are connected like this:
> > 
> > A --- B --- C
> > 
> > Both Router B and Router C are defined as BSR candidates, Router B for
> > 225.13.0.0/24 (eth1, 10.0.0.1) and Router C for 225.12.0.0/24 (eth1,
> > 10.0.0.2).
> > 
> > I would expect to see both 10.0.0.1 and 10.0.0.2 as BSRs on Router A,
> > but command "show pim bootstrap" on Router A shows only one BSR:
> 
> You need to check the following:
> 
> * Are the Bootstrap messages from C forwarded by B on the
>   A-B subnet.
>   For that purpose you need to use a tool like tcpdump or
>   wireshark that understands the Bootstrap messages format so you
>   could match the content. Note that the Bootstrap messages are
>   processed hop-by-hop such that only the payload of the message is
>   preserved, but the IP header is replaced (i.e., the src IP address
>   won't match the BSR IP address).
> 
> * Check that the (unicast) reverse-path forwarding information in A
>   points to B as the next-hop toward C.
> 
> * Check for any suspicious warning or error messages in the XORP log
>   output.

Ignore the above.
On second thought, I think the problem is that inside your
"scope-zone {}" nodes you must set "is-scope-zone: true",
because it is false by default.

For reason for that is according to the PIM BSR spec there is one
BSR state machine per scope zone.
If a configured zone's "is-scope-zone" flag is false, then it
automatically belongs to the global 224.0.0.0/4 non-scoped zone.
I.e., in your configuration both configured entries for
225.13.0.0/24 and 225.12.0.0/24 will be controlled by the same state
machine.

Setting the "is-scope-zone" flag to true for at least one of them
will put them on separate state machines, but a good practice would
be to enable the "is-scope-zone" flag for both of them.

Please let me know whether this fixes the problem.

Pavlin



> Pavlin
> 
> > > show pim bootstrap
> > Active zones:
> > BSR             Pri LocalAddress    Pri State           Timeout SZTimeout
> > 10.0.0.2          1 0.0.0.0           0 AcceptPreferred      73      1243
> > Expiring zones:
> > BSR             Pri LocalAddress    Pri State           Timeout SZTimeout
> > Configured zones:
> > BSR             Pri LocalAddress    Pri State           Timeout SZTimeout
> > 
> > 
> > 
> > ---Router A---
> > 
> > interfaces {
> >     interface eth1 {
> >         default-system-config
> >     }
> > }
> > 
> > protocols {
> >   static {
> >     route 10.0.0.0/24 {
> >       next-hop: 11.0.0.1
> >     }
> >   }
> > }
> > 
> > protocols {
> >   pimsm4 {
> >     interface eth1 {
> >       vif eth1 {
> >       }
> >     }
> > 
> >     interface register_vif {
> >       vif register_vif {
> >       }
> >      }
> > 
> >     bootstrap {
> >     }
> >   }
> > }
> > 
> > protocols {
> >   fib2mrib {
> >   }
> > }
> > 
> > plumbing {
> >   mfea4 {
> >     interface eth1 {
> >       vif eth1 {
> >       }
> >     }
> >     interface register_vif {
> >       vif register_vif {
> >       }
> >     }
> >   }
> > }
> > 
> > 
> > ---Router B---
> > 
> > interfaces {
> >     interface eth1 {
> >         default-system-config
> >     }
> >     interface eth2 {
> >         default-system-config
> >     }
> > }
> > 
> > protocols {
> >   pimsm4 {
> >     interface eth1 {
> >       vif eth1 {
> >       }
> >     }
> > 
> >     interface eth2 {
> >       vif eth2 {
> >       }
> >     }
> > 
> >     interface register_vif {
> >       vif register_vif {
> >       }
> >     }
> > 
> >     bootstrap {
> >       cand-bsr {
> >         scope-zone 225.13.0.0/24 {
> >           cand-bsr-by-vif-name: "eth1"
> >          }
> >       }
> >     }
> >   }
> > }
> > 
> > protocols {
> >   fib2mrib {
> >   }
> > }
> > 
> > plumbing {
> >     mfea4 {
> >         interface eth1 {
> >             vif eth1 {
> >             }
> >         }
> >         interface eth2 {
> >             vif eth2 {
> >             }
> >         }
> >         interface register_vif {
> >             vif register_vif {
> >             }
> >         }
> >     }
> > }
> > 
> > 
> > ---Router C---
> > 
> > interfaces {
> >     interface eth1 {
> >         default-system-config
> >     }
> > }
> > 
> > protocols {
> >   static {
> >     route 11.0.0.0/24 {
> >       next-hop: 10.0.0.1
> >     }
> >   }
> > }
> > 
> > protocols {
> >   pimsm4 {
> >     interface eth1 {
> >       vif eth1 {
> >       }
> >     }
> > 
> >     interface register_vif {
> >       vif register_vif {
> >       }
> >     }
> > 
> >     bootstrap {
> >       cand-bsr {
> >         scope-zone 225.12.0.0/24 {
> >           cand-bsr-by-vif-name: "eth1"
> >         }
> >       }
> >     }
> >   }
> > }
> > 
> > protocols {
> >   fib2mrib {
> >   }
> > }
> > 
> > plumbing {
> >     mfea4 {
> >         interface eth1 {
> >             vif eth1 {
> >             }
> >         }
> >         interface register_vif {
> >             vif register_vif {
> >             }
> >         }
> > 
> >     }
> > }
> > 
> > _______________________________________________
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> > Xorp-users at xorp.org
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> 
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