[Xorp-users] can not receive multicast data packet

[Pavlin Radoslavov]

李彬 <libin020989 at sohu.com> wrote:

> I'm using xorp to build a network,xorp connects to a multicast source and a multicast receiver,when I send UDP packets on the source,I can not receive the packets on the receiver,I can not find the reason,
> Here is the xorp's state

The state looks fine.
Two reasons come to mind:

* Firewall entries in the kernel that prevent the multicast data
  from being forwarded.
* TTL is too small: by default the multicast data packets are
  transmitted by TTL of 1 and such packets won't be forwarded. Make
  sure that the TTL at the sender is large enough to reach the
  receivers; if a have a single router in the middle TTL=2 should be
  sufficient.

Regards,
Pavlin

> root at netbsd> show igmp group 
> IF     Group           Source          LastReported Timeout V  S    v1T    v2T
> rtk0   224.3.3.20      0.0.0.0         192.168.111.100     145 3  E     0     0
> root at netbsd> show pim mfc 
> Group           Source          RP             
> 224.3.3.20      192.168.222.35  14.14.14.14    
>     Incoming interface :      bce0
>     Outgoing interfaces:      .O.
> root at netbsd> show pim join 
> Group           Source          RP              Flags
> 224.3.3.20      0.0.0.0         14.14.14.14     WC   
>     Upstream interface (RP):   bce0
>     Upstream MRIB next hop (RP): 192.168.55.1
>     Upstream RPF'(*,G):        192.168.55.1
>     Upstream state:            Joined 
>     Join timer:                32
>     Local receiver include WC: .O.
>     Joins RP:                  ...
>     Joins WC:                  ...
>     Join state:                ...
>     Prune state:               ...
>     Prune pending state:       ...
>     I am assert winner state:  ...
>     I am assert loser state:   ...
>     Assert winner WC:          ...
>     Assert lost WC:            ...
>     Assert tracking WC:        OO.
>     Could assert WC:           .O.
>     I am DR:                   .OO
>     Immediate olist RP:        ...
>     Immediate olist WC:        .O.
>     Inherited olist SG:        .O.
>     Inherited olist SG_RPT:    .O.
>     PIM include WC:            .O.
> root at netbsd> show igmp interface 
> Interface    State    Querier         Timeout Version Groups
> bce0         UP       192.168.55.1         98       3      0
> rtk0         UP       192.168.111.10     None       3      1
> root at netbsd> show pim interface 
> Interface    State    Mode   V PIMstate Priority DRaddr          Neighbors
> bce0         UP       Sparse 2 NotDR           1 192.168.55.1            1
> rtk0         UP       Sparse 2 DR              1 192.168.111.10          0
> register_vif UP       Sparse 2 DR              1 192.168.111.10          0
> 
> 
> 
> 
> 李彬
> 2008-05-07
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