ā02-16-2012 09:09 AM - edited ā03-04-2019 03:18 PM
IP multicast documentation suggest the "no ip mutlicast ttl-threshold" command to fix an issue I am experiencing
however my ios (12.1(19) )does not support that command
could find nothing in command reference
issue is allworx phone system - directly connected to 4507
the paging feature uses mutlicast - it works for 2 minutes across layer 3 vlan interfaces and then fails until voip phones are rebooted
the phone requests to send the page - the allworx controller sends out the muticast advertisments.
sho ip mroute does show T flag - which = SPT bit set
the expirey field decriments until paging fails see below
I also see incrimenting bad hop count in show ip traffic - a symptom one of the multicast troubleshooting documents described
(10.57.100.30, 239.255.10.1), 00:01:49/00:01:20, flags: T
Incoming interface: Vlan99, RPF nbr 0.0.0.0
Outgoing interface list:
Vlan6, Forward/Sparse, 00:01:49/00:01:13, H -expirey filed is 00:01:13 - paging still function across layer 3 vlan interfaces ( this has decirmented from a higher value )
(*, 239.255.10.1), 00:02:34/stopped, RP 0.0.0.0, flags: DC
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Vlan99, Forward/Sparse, 00:02:30/00:00:34, H
(10.57.100.30, 239.255.10.1), 00:02:11/00:02:55, flags: PT - mroute is pruned at this point paging fails across layer 3 vlan interfaces on core
Incoming interface: Vlan99, RPF nbr 0.0.0.0
Outgoing interface list: Null
we tried setting the paging hop count to 5 in allworx ( I asume this reflects TTL)
allworks support wasn't much help.
ā12-04-2012 12:48 PM
Found the issue
we first upgraded the 4507 to 150-2.SG4
but that initself did not change any behavior
after closer inspection of traffic captures between IP phones and Allworx ( the multicast server)
I found that Allworx isn't always using multicast but sends broadcasts ( the allworx ip is x.x.130.1 so boradcast is x.x.130.255)
the ip multicast-helper on the layer 3 interface did the trick
I had to convert broadcast to multicast on the layer3 interface of the server
first use and acl to define the traffic
access-list 139 permit UDP host x.x.130.1 host x.x.130.255 eq 2088
then convert broadcast to multicast
ip multicast helper-map broadcast 239.255.10.0 139
and then do the reverse ( multicast to broadcast) at the far end
I used the same acl number but defined it differently
access-list 139 permit udp host x.x.130.1 any eq 2088
ip multicast helper-map 239.255.10.0 x.x.152.255 139
my challenge is now how to handle different multicast groups as the traffic x.x.130.1 UDP 2088 does not change
only the mutlicast group
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