From: Scott Morris (smorris@ipexpert.com)
Date: Tue Dec 11 2007 - 13:37:28 ART
Ok, fair enough. So let's look at it in that aspect....
Your PCs don't speak PIM. But they do speak IGMP. If your router on that
same interface is not setup to enable IGMP, then what good does it do? PC's
send messages to 224.0.0.2 (AllRouters) for IGMP, but any non-participating
routers will simply discard those packets.
Even though PIM is enabled towards the users, it uses a separate group
(224.0.0.13) to discover neighbors. if there are no other neighbors in the
PIM world, this indicates to the router that it is a stub end with hosts
only. So it provides perspective.
Also, PIM enables participation in the IIL/OIL of an mroute. No PIM, no
participation. No participation, no multicast forwarding.
For your definitions, a headend (e.g. in cable world the node of cable
company) is actually a sender. While I suppose it could receive as well
(propogation of like information within backbone of provider to replicate
among nodes), the groups would be separate and perhaps a separate multipcast
domain entirely.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
A Cisco Learning Partner - We Accept Learning Credits!
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
-----Original Message-----
From: Salau, Yemi [mailto:yemi.salau@siemens.com]
Sent: Tuesday, December 11, 2007 9:51 AM
To: Scott Morris; Sridhar Vaidyanathan; Cisco certification
Subject: RE: Multicast on interface on which hosts is connected
Hello Scott/GS,
Yes IGMP is automatically enabled when PIM is, but the question Sridhar
asked is if it's required to enable PIM on interface that connects to
multicast receivers. Maybe I'm the one not getting it straight, but if he's
talking to a normal headend like STBs, or PCs or anyother multicast client
for that matter, I would say No.
Another insight into this: the normal setup of things is to connect up a
Layer 3 Switch to the Stub Router, and then you need to enable PIM on the
Router's fastethernet interface that connects to the VLAN Domain where the
multicast receivers belongs to. But if these receivers are connected to the
Stub Router Directly, I presume the Router will act as the gateway out of
the LAN domain. So, the PC needs not speak PIM to the Router in this
scenerio, but if it's the former scenerio, ofcourse, you need to setup a PIM
Path/Mroute all the way to the nearest PIM device that connects to the
multicast receivers, I'm not sure there is any RFC recommendations to allow
multicast devices speak PIM to the receivers.
NB: My definition of Receivers are Headends which actually receives the
Multicast Traffic. Yours might be different, so please clarify.
Many Thanks
Yemi Salau
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott Morris
Sent: Tuesday, December 11, 2007 2:17 PM
To: 'Sridhar Vaidyanathan'; 'Cisco certification'
Subject: RE: Multicast on interface on which hosts is connected
Use "show ip igmp interfaces" to help you answer this.... PIM and IGMP are
enabled at the same time. (short answer = yes)
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
A Cisco Learning Partner - We Accept Learning Credits!
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Sridhar Vaidyanathan
Sent: Tuesday, December 11, 2007 3:17 AM
To: Cisco certification
Subject: Multicast on interface on which hosts is connected
Dear All,
Is it required for enabling PIM on a fastethernet interface which is
connected to Multicast receivers? Assuming that the router is a Stub Router
and has one serial connection through which the router receives multicast
feeds and PIM is enabled on the serial interface.
Regards,
Sridhar.
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