All things related to multicast

[Marshall Eubanks <>]

Hello;

We have noticed an odd pattern of packet loss to nysernet (AS 3754) from 
MulticastTech
(AS 16517). Although the packet loss is not high over all (~ 2.5%), there is 
a period
of about 1.5 seconds every 65 seconds where the packet loss is near total.

http://www.multicasttech.com/rr/nysernet.wednesday.ps

shows this with 2 second averages. The repeat period is 65 seconds to pretty 
high accuracy
(65.0056 seconds averaged over a day), so
this must be some sort of periodic router reset/refresh/etc. This has 
apparently repeated this
way since last Friday (when our data begin).

Now, we also have traces to U Oregon during the same period, and these do NOT 
show the same
loss pattern, so the problem is not at our end. However, as the Oregon path 
goes from
us to Sprint and the Nysernet path goes through vBNS, this does not narrow 
things down
much.

Here are traces from Nysernet to us :

   Mtrace from 63.105.122.14 to 199.109.32.33 via group 233.64.133.20
   Querying full reverse path...
     0 adelie.nysernet.org (199.109.32.33)
    -1 c7206-1.nysernet.org (199.109.32.254) PIM/BGP4+ thresh^ 0 Reached 
RP/Core
    -2 ? (199.109.2.18) PIM thresh^ 1
    -3 clev-ipls.abilene.ucaid.edu (199.109.2.2) PIM/BGP4+ thresh^ 0 Reached 
RP/Core
    -4 ipls-clev.abilene.ucaid.edu (198.32.8.25) PIM/BGP4+ thresh^ 0 Reached 
RP/Core
    -5 jn1-at1-1-0-2008.dng.vbns.net (204.147.128.13) PIM thresh^ 1
    -6 jn1-so7-0-0-0.nor.vbns.net (204.147.136.147) PIM thresh^ 1
    -7 jn1-so7-0-0-0.wor.vbns.net (204.147.136.133) PIM thresh^ 1
    -8 jn1-so7-0-0-0.wae.vbns.net (204.147.136.136) PIM thresh^ 1
    -9 Multicast-inc.wae.vbns.net (204.147.129.90) PIM thresh^ 0 Reached 
RP/Core
   -10 hendrix.multicasttech.com (63.105.122.14)
   Round trip time 293 ms; total ttl of 9 required.

   traceroute to 63.105.122.14 (63.105.122.14), 30 hops max, 40 byte packets
    1 c7206-1.nysernet.org (199.109.32.254) 1 ms 54 ms 1 ms
    2 199.109.2.18 (199.109.2.18) 52 ms 5 ms 5 ms
    3 199.109.5.54 (199.109.5.54) 58 ms 14 ms 14 ms
    4 199.109.5.2 (199.109.5.2) 32 ms 15 ms 14 ms
    5 wash-nycm.abilene.ucaid.edu (198.32.8.45) 19 ms 19 ms 19 ms
    6 vbns-abilene.abilene.ucaid.edu (198.32.11.10) 24 ms 23 ms 24 ms
    7 Multicast-inc.wae.vbns.net (204.147.129.90) 35 ms 35 ms 40 ms
    8 hendrix.multicasttech.com (63.105.122.14) 34 ms 36 ms 37 ms


Anyone out there know why 65 seconds is a magic number ? Anyone have any 
ideas ?

                                   
                                   Marshall Eubanks (with Hans Kuhn and Bill 
Owens)


    Multicast Technologies, Inc.
   10301 Democracy Lane, Suite 410
   Fairfax, Virginia 22030
   Phone : 703-293-9624          Fax     : 703-293-9609     
   e-mail : 

     http://www.on-the-i.com