From: gladston@br.ibm.com
Date: Thu May 19 2005 - 11:02:22 GMT-3
What do you think of this situation?
R4 multicast NTP with key 10 to default group, on vlan 47.
CAT1 should receive NTP multicast on its interface vlan 47
R4 is physically connected to CAT2 fa0/4. CAT2 is trunked with CAT1.
If I do not enable ip multicast and PIM on R4 and CAT1, CAT1 does not receive group 224.0.1.1 (NTP).
I think it was supposed to receive, because they are on the same LAN. And that is true for R4----R7 on vlan 4 (other test, where R4 is connected to R7 through CAT1, just layer 2). It is not necessary to enable multicast routing in this case.
But it seems that CAT2 on the middle of the communication between R4 and CAT2 does not let multicast traffic arrive on CAT2 Vlan 47.
It must be IGMP snooping blocking the multicast. What do you think?
Rack2CAT1#sh ntp ass
address ref clock st when poll reach delay offset disp
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
Rack2CAT1(config)#ip multicast-routing
Rack2CAT1(config)#int vla 47
Rack2CAT1(config-if)#ip pim sparse-d
Rack2CAT1#sh ip igmp snooping group
Vlan Group Version Port List
---------------------------------------------------------
20 224.0.1.1 v2 Fa0/13
20 224.0.1.40 v2 Fa0/13
47 224.0.1.1 v2 Fa0/14
56 224.0.1.39 v2 Fa0/5
56 239.1.1.1 v2 Fa0/6
Rack2CAT1#
Rack2CAT1#sh ip igmp snooping mrou
Vlan ports
---- -----
14 Fa0/1(dynamic)
20 Fa0/13(dynamic)
47 Fa0/14(dynamic), Router
56 Fa0/5(dynamic)
Rack2CAT1#
Rack2CAT1#sh ip igmp snooping ?
group Show group address information
mrouter Show routers on Catalyst Vlans
querier Show IGMP querier information
vlan Snooping info in a Catalyst Vlan
| Output modifiers
<cr>
Rack2CAT1#sh ip igmp snooping que
Vlan IP Address IGMP Version Port
---------------------------------------------------
14 150.100.20.1 v2 Switch
20 142.20.28.2 v2 Fa0/13
47 142.20.47.4 v2 Fa0/14
56 142.20.56.5 v2 Fa0/5
Rack2CAT1#sh ntp ass
address ref clock st when poll reach delay offset disp
* 142.20.47.4 142.20.6.1 12 15 64 2 2.3 -0.65 15875.
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
Rack2CAT1#
Rack2CAT1#
Rack2CAT1#sh ntp ass det
142.20.47.4 dynamic, authenticated, our_master, sane, valid, stratum 12
ref ID 142.20.6.1, time C636EE4E.1A2D8492 (10:51:58.102 UTC Thu May 19 2005)
our mode bdcast client, peer mode server, our poll intvl 64, peer poll intvl 64
root delay 64.36 msec, root disp 1.01, reach 2, sync dist 15909.348
delay 2.30 msec, offset -0.6475 msec, dispersion 15875.02
precision 2**18, version 3
org time C636EE78.5E78A95C (10:52:40.369 UTC Thu May 19 2005)
rcv time C636EE78.5EEE9BB9 (10:52:40.370 UTC Thu May 19 2005)
xmt time C636EE78.5E41CF69 (10:52:40.368 UTC Thu May 19 2005)
filtdelay = 2.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00
filtoffset = -0.65 0.00 0.00 0.00 0.00 0.00 0.00 0.00
filterror = 0.02 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0
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