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New Member

IGMP is disabled on interface

How can I enable IGMP on an interface?

here is a piece of the config:

ip multicast-routing

!

interface Vlan1

ip address 192.168.1.174 255.255.255.248

no ip proxy-arp

ip tcp adjust-mss 1440

ip igmp proxy-service

fair-queue

!

router#sho ip multicast

Multicast Routing: enabled

Multicast Multipath: disabled

Multicast Route limit: No limit

Multicast Triggered RPF check: disabled

Multicast Fallback group mode: Sparse

Multicast DVMRP Interoperability: disabled

router#sho ip multicast int vlan 1

Vlan1 is up, line protocol is up

Internet address is 192.168.1.174/29

Multicast routing: disabled

Multicast packets in/out: 32/0

Multicast TTL threshold: 0

Multicast Tagswitching: disabled

6 REPLIES

Re: IGMP is disabled on interface

Issue the command ip pim spare-dense-mode under the vlan interafces

int vlan 1

ip pim spare-dense-mode

By default igmp snooping is enabled on all interfaces. you can check this using sh ip igmp snooping

Ypu would also need to have the global ip multicast-routing command on the devcie

HTH

Narayan

New Member

Re: IGMP is disabled on interface

I'm affraid that c850-advsecurityk9-mz.124-15.T1 doesn't have ip pim at all.

How does ip igmp snooping help with multicast routing? Of course, ip multicast-routing is enabled in global config.

Re: IGMP is disabled on interface

Well you nevert mentioned you have a 85X router.

I am not sure whether these routers support multicast but the IOS image mentioned does not show this as a feature in the feature navigator

www.cisco.com/go/fn

HTH

Narayan

New Member

Re: IGMP is disabled on interface

I don't know either. It has a complete set of igmp commands as well as ip multicast and mroute for static routes.

and look at it again:

router#sho ip multicast

Multicast Routing: enabled

Multicast Multipath: disabled

Multicast Route limit: No limit

Multicast Triggered RPF check: disabled

Multicast Fallback group mode: Sparse

Multicast DVMRP Interoperability: enabled

It seems that it's already in sparse mode.

I do not understand it :(

Cisco Employee

Re: IGMP is disabled on interface

Victor,

IGMP is automatically enabled when you configure PIM on the interface.

ip pim sparse-mode

Regards,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: IGMP is disabled on interface

I don't have ip pim.

Is it possible / sensible to build the distribution tree by hands. I'm only interested in one multicast group distributed over 16 cisco851. The router can join it manually by means of ip igmp join-group 234.0.0.1 on the interface I need. Can I possible let others know about this group without pim?

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