Multicast PIM Sparse

[dpmp]

Dear community,

I'm using Multicast PIM Sparse Mode in my network setup.

The command

Code: Select all

show ip multicast group

shows me a Life-counter, which is the countdown of the life time of the IGMP group membership.
(see attachment)

Now, my questions:

1) Who sets the Life-counter to its value: Switch or Streaming Server?
2) If the switch sets this value, can I change this starting value to a different one? Command?

Many thanks in advanced and best regards

Daniel

[silvio]

Hi Daniel,
your router (the switch with an ip interface in the vlan) is the mc-querier. The mc-client joins the group via igmp only one time at the start of the mc session. The querier regulary (125 sec.) ask the client if it is still interested in the mc stream. The client has to answer. If there is no answer than the stream will not be forwarded after elapsing of the life timer. So the timer is from your switch. At your PIM-router mc-querying will be activated in the specific vlan. You can activate querying at all your switches.

> ip multicast querying enable
> show ip multicast
Status = enabled,
Querying = enabled,

regards
Silvio

[dpmp]

Dear Silvio,

but the issu is that we are using some old streaming client boxes (TV), which are only connected with 10 Mbit/s half.
When we are zapping through the TV channels, we are requesting at every channel switch a new multicast steam.
So, that causes a lot of bandwith usage and the image of the current chosen TV channel starts to lag (artefacts).

When some streams are timed out (Life Timer expires) the picture of the current stream is getting better.

So thats the reason for my initial question?

Is there a way to change the Life Timer for a multicast group? I want to tear it down.

Or is there another way to solve my issue.

Best Regards

Daniel

[silvio]

Hi Daniel,
now this is more clear to me (with this 10Mbit-connection )

look at your Intervalls:
6850-Core> show ip multicast

Status = enabled,
Querying = enabled,
Proxying = disabled,
Spoofing = disabled,
Zapping = disabled,
Querier Forwarding = disabled,
Flood Unknown = disabled,
Buffer Packet = disabled,
Version = 2,
Robustness = 2,
Query Interval (seconds) = 125,
Query Response Interval (tenths of seconds) = 100,
Last Member Query Interval (tenths of seconds) = 10,
Unsolicited Report Interval (seconds) = 1,
Router Timeout (seconds) = 90,
Source Timeout (seconds) = 30,
Max-group = 0,
Max-group action = none,
Helper-address = 0.0.0.0,
Index Sharing = disabled

you can try to degrease the query Intervall. Maybe it is an idea to limit the max-group.

6850-Core> ip multicast q?
^
QUERYING QUERY-RESPONSE-INTERVAL QUERY-INTERVAL
QUERIER-FORWARDING

6850-Core> ip multicast max-group ?
^
<cr> ACTION <num>

regards
Silvio