perfsonar development work

[Stig Venaas <>]

Nicolas Simar wrote:
> Hi,
>
> could you please provide a use case describing in which case we would 
> use it?
>
> Thanks a lot :)

OK, let me try to give you one example. Let us say that we want to
trace the multicast path from a receiver to the source (or it may stop
before reaching the source). For each router we use the command
"show ip mroute" on Cisco.

Assume that I have joined a multicast group 232.43.211.234 and that
we want to trace the Shortest Path Tree towards the known sources.

On lasthop router (the one I as a receiver am connected to)

show ip mroute 232.43.211.234

the interesting output is:

(158.38.0.230, 232.43.211.234), 00:01:43/00:02:55, flags: sTI
  Incoming interface: Vlan2, RPF nbr 128.39.47.89, RPF-MFD
  Outgoing interface list:
    Vlan20, Forward/Sparse, 00:01:43/00:02:55, H

Here I pick up the source address 158.38.0.230 and we want to
trace this. We also see RPF nbr 128.39.47.89. This is the next
hop up the tree.

On 128.39.47.89:

show ip mroute 232.43.211.234 158.38.0.230

Output:
(158.38.0.230, 232.43.211.234), 00:03:39/00:03:23, flags: sT
  Incoming interface: GigabitEthernet0/3, RPF nbr 128.39.46.173
  Outgoing interface list:
    GigabitEthernet0/1.18, Forward/Sparse, 00:03:39/00:02:47

We found 128.39.46.173. On that one we get:

show ip mroute 232.43.211.234 158.38.0.230

Output:
(158.38.0.230, 232.43.211.234), 00:00:37/00:02:52, flags: sT
  Incoming interface: Vlan20, RPF nbr 0.0.0.0, RPF-MFD
  Outgoing interface list:
    Vlan2, Forward/Sparse, 00:00:37/00:02:52, H

Here we get RPF 0.0.0.0 and we stop. Some further analysis is
needed to see if we really reached the source or not. On Cisco
you can check if you reached the source with "show ip rpf".
It should say:
RPF neighbor: ? (158.38.0.230) - directly connected
if you reached the source.

This should give you some idea what can be done.

Note that on Juniper you probably would do
show pim join 232.43.211.234
and get:

Group: 232.43.211.234
    Source: 158.38.0.230
    Flags: sparse,spt
    Upstream interface: ge-1/0/1.0

This shows we have state for the source. and that we have found
an upstream interface. It does however not say what it is, like
Cisco did. One option here is:

show multicast rpf 158.38.0.230

It may show

158.38.0.224/28
    Protocol: Direct
    Interface: ge-1/0/1.0

if directly conected (which means we've found the source). Or
if not, e.g.:
158.38.0.224/28
    Protocol: IS-IS
    Interface: ge-6/3/0.0
    Neighbor: 128.39.65.74

which means we should continue tracing at 128.39.65.74.

Stig
> Cheers,
> Nicolas
>
> Nina Jeliazkova wrote:
> > Jeff,
> >
> > I guess nobody had suggested this so far - otherwise I think it is 
> > very good option.
> >
> > Regards,
> > Nina
> >
> > Jeff W. Boote wrote:
> > > Hi Nina, Candido,
> > >
> > > Is there any reason we could not publish the metadata service URL in 
> > > the LS, and then fetch it from there? Hopefully there will be more 
> > > than one authentication federation in use soon and I suspect it will 
> > > be easier for users if they can be presented with choices instead of 
> > > making them specify things like this.
> > >
> > > Thanks,
> > > jeff
> > >
> > > On May 31, 2008, at 6:19 AM, 
> > >
> > >  wrote:
> > >
> > > > Author: nina
> > > > Date: 2008-05-31 08:19:14 -0400 (Sat, 31 May 2008)
> > > > New Revision: 3932
> > > >
> > > > Modified:
> > > >   
> > > > branches/perfsonarui/src/org/perfsonar/perfsonarui/aa/AAPerfsonarRequest.java 
> > > >
> > > >   
> > > > branches/perfsonarui/src/org/perfsonar/perfsonarui/test/ls/LSTest.java
> > > >   
> > > > branches/perfsonarui/src/org/perfsonar/perfsonarui/ui/PerfsonarModel.java 
> > > >
> > > > Log:
> > > > Introduced a new command line option
> > > >
> > > > -m,--mds <URL>                        URL of Metadata Service, used to
> > > >                                       retrieve the list of Identity 
> > > > Providers, default http://mds.rediris.es:8080
> > > > in relation to Bug 461
> > > > https://bugzilla.perfsonar.net/show_bug.cgi?id=461