All things related to multicast

[Marshall Eubanks <>]

"Michael H. Lambert" wrote:
> 
> All,
> 
> I'm probably just demonstrating my cluelessness, but a session we are trying
> to announce isn't making it to Abilene and I can't figure out why.
> 
> Topology (PIM SM [or Sparse/Dense] on all interfaces):
> 
>    +-------+                 +-------+                  +--------+
>    |Abilene|  BGP UC+MC NLRI |GigaPoP|  Static mroutes  |Internal|
>    | Core  |<--------------->|Border |<---------------->| Campus |
>    |Router |      MSDP       |Router |       MSDP       | Router |
>    +-------+                 +-------+                  +--------+
> 
> Note:  The "Internal Campus Router" is not our campus unicast border routers
> (which are a pair of UNIX boxes running GateD and screend).
> 
> The multicast boundary and SA filter access lists are at least close to the
> BCP.
> 
> A host inside our campus is announcing a session.  On our internal router, I
> see (from "show ip mroute 224.2.127.254"):
> 
> (128.182.61.51, 224.2.127.254), 00:04:04/00:00:01, flags: CLTA
>   Incoming interface: GigabitEthernet5/0/0.1, RPF nbr 0.0.0.0
>   Outgoing interface list:
>     ATM0/0.2, Forward/Sparse-Dense, 00:04:04/00:03:25
>     GigabitEthernet5/0/0.7, Forward/Sparse-Dense, 00:04:04/00:02:54
> 
> My understanding of the flags is that "A" means that this (S,G) (and any
> session announcements in it) is being announced via MSDP.
> 
> Now, on our GigaPoP border router:
> 
> (128.182.61.51, 224.2.127.254), 00:31:58/00:02:19, flags: CLMT
>   Incoming interface: ATM5/0/0.2, RPF nbr 192.88.115.130, Mroute
>   Outgoing interface list:
>     ATM5/0/0.4, Forward/Sparse-Dense, 00:31:10/00:02:35
>     ATM5/0/0.6, Forward/Sparse-Dense, 00:31:11/00:03:04
>     Loopback0, Forward/Sparse-Dense, 00:31:58/00:02:51
>     ATM5/0/0.3, Forward/Sparse-Dense, 00:31:58/00:02:55
> 
> The "M" flag suggests that this router is hearing the (S,G) via MSDP, but I
> take it that the lack of an "A" flag means it is not being announced.  The
> RPF neighbor is correct.  In fact, if I do a "show ip rpf 128.182.61.51" on
> the Abilene core router (CLEV), I get the expected result.  (None of the
> outgoing interfaces is the Abilene interface.)
> 
> My understanding is that nobody in the outside world can see our session
> announcement unless (128.182.61.51, 224.2.127.254) is announced to Abilene
> by our border router.
> 
> I'm at a loss as to how to track this one down.  Can anyone offer any
> suggestions?
> 
> Michael
> 
> +-------------------------------------------------------------------------+
> | Michael H. Lambert, Network Engineer             Phone: +1 412 268-4960 |
> | Pittsburgh Supercomputing Center                 FAX:   +1 412 268-8200 |
> | 4400 Fifth Avenue, Pittsburgh, PA  15213         
> 
>         |
> +-------------------------------------------------------------------------+

Well, you are in our MBGP tables, but we can't see your MSDP, and, of
course, that means we can't get you.

Do you have your MSDP peer at Abilene configured ? What does

show ip msdp peer

reveal ?

The rest of this is results from various probes done from here, which
might be of some use :

multicasttech-2>show ip msdp sa | include 128.182
multicasttech-2>
multicasttech-2>show ip mbgp 128.182.61.51
BGP routing table entry for 128.182.0.0/16, version 733136
Paths: (2 available, best #2, table NULL)
Flag: 0x208
  Not advertised to any peer
  3300 704 10888 11537 5050
    195.90.65.9 from 195.90.65.9 (195.206.65.6)
      Origin IGP, localpref 100, valid, external
  1239 11537 5050
    160.81.38.225 from 160.81.38.225 (144.228.242.54)
      Origin IGP, metric 76, localpref 100, valid, external, best
multicasttech-2>show ip rpf 128.182.61.51 
RPF information for sandoz.psc.edu (128.182.61.51)
  RPF interface: Serial3/1:0
  RPF neighbor: sl-gw5-rly-9-0-0-TS19.sprintlink.net (160.81.38.225)
  RPF route/mask: 128.182.0.0/16
  RPF type: mbgp
  RPF recursion count: 0
  Doing distance-preferred lookups across tables
multicasttech-2>

Can you get our multicasts (such as 
Group: 233.64.133.20, On-The-I.com Channel-2 160kbs MP3 Audio
   Source: 63.105.122.14 (hendrix.multicasttech.com) ) ?


                                   Regards
                                   Marshall Eubanks

P.S. I would urge you to put up a multicast beacon and contribute to the
NLANR monitoring effort.(For the record, this is described at

http://dast.nlanr.net/Projects/Beacon/

General beacon site :
http://beaconserver.accessgrid.org:9999/
Abilene beacon site :
http://palpatine.ucs.indiana.edu:9999/  )


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