Re: Question about proxy implemenation in RFC 4605

Kunal Shah <[email protected]> Mon, 1 Nov 2010 14:30:55 -0400
Newsgroups	gmane.ietf.magma
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Hi Alvaro,

For a router to determine that there are no interested hosts on the LAN, it=
 does send out group specific or source-group specific queries. Does this m=
ean, that the proxy device should send out source-group specific queries on=
 other interfaces when deemed required?? How will this scale if there are a=
 large number of interfaces??

Kunal

________________________________
From: Alvaro Fernandez [mailto:[email protected]]
Sent: Saturday, October 30, 2010 10:36 AM
To: Kunal Shah
Cc: [email protected]
Subject: RE: [magma] Question about proxy implemenation in RFC 4605


Hi Kunal

I read it years ago but I think RFC 4605 explains that the downstream netwo=
rk interface should behave like a router, so the solution is in the state m=
achine explained in RFC3376 for the IGMPv3 router

=C1lvaro


-----Mensaje original-----
De: [email protected] en nombre de Kunal Shah
Enviado el: s=E1b 30/10/2010 2:46
Para: [email protected]
Asunto: [magma] Question about proxy implemenation in RFC 4605

Hi all,

According to RFC 4605, a router creates a membership database after merging=
 the subscriptions on individual interfaces. Lets say that 3 IGMPv3 capable=
 interfaces are as follows:

Interface 1 has host reporting Include S1 -> I(S1)
Interface 2 has host reporting Exclude S2 -> E(0,S2)
Interface 3 has host reporting Exclude nothing -> E(0,0)

For a device doing IGMPv3 proxy, the final membership record for group G is=
 (G, EXCLUDE, NULL). Now lets say the host on interface 3 goes away, becaus=
e of which the subscription on interface 3 would expire and there wont be a=
ny IGMPv3 state on interface 3.  How would the new membership record for PR=
OXY be calculated?? The RFC does not suggest any way to do this. Would IGMP=
 process have to go through each interface again and then recompute the new=
 membership record?? This would be very inefficient especially if there are=
 multiple interfaces.
Is there a better way to recompute the new membership record??


Thanks
Kunal




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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>RE: [magma] Question about proxy implemenation in RFC 46=
05</TITLE>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-8859-1"=
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<BODY>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D945352418-01112010><FONT face=3DA=
rial=20
color=3D#0000ff size=3D2>Hi Alvaro,</FONT></SPAN></DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D945352418-01112010><FONT face=3DA=
rial=20
color=3D#0000ff size=3D2></FONT></SPAN>&nbsp;</DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D945352418-01112010><FONT face=3DA=
rial=20
color=3D#0000ff size=3D2>For a router to determine that there are no intere=
sted=20
hosts on the LAN, it does send out group specific or source-group specific=
=20
queries. <SPAN class=3D945352418-01112010><FONT face=3DArial color=3D#0000f=
f=20
size=3D2>Does this mean, that the proxy device should send out source-group=
=20
specific queries on other interfaces when deemed required?? How will this s=
cale=20
if there are a large number of interfaces??</FONT></SPAN></FONT></SPAN></DI=
V>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D945352418-01112010><FONT face=3DA=
rial=20
color=3D#0000ff size=3D2><SPAN=20
class=3D945352418-01112010></SPAN></FONT></SPAN>&nbsp;</DIV>
<DIV dir=3Dltr align=3Dleft><SPAN class=3D945352418-01112010><FONT face=3DA=
rial=20
color=3D#0000ff size=3D2><SPAN=20
class=3D945352418-01112010>Kunal</SPAN></FONT></SPAN></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> Alvaro Fernandez=20
[mailto:[email protected]] <BR><B>Sent:</B> Saturday, October 30, 2010 1=
0:36=20
AM<BR><B>To:</B> Kunal Shah<BR><B>Cc:</B> [email protected]<BR><B>Subject:</B>=
 RE:=20
[magma] Question about proxy implemenation in RFC 4605<BR></FONT><BR></DIV>
<DIV></DIV><!-- Converted from text/plain format -->
<P><FONT size=3D2>Hi Kunal<BR><BR>I read it years ago but I think RFC 4605=
=20
explains that the downstream network interface should behave like a router,=
 so=20
the solution is in the state machine explained in RFC3376 for the IGMPv3=20
router<BR><BR>=C1lvaro<BR><BR><BR>-----Mensaje original-----<BR>De:=20
[email protected] en nombre de Kunal Shah<BR>Enviado el: s=E1b 30/10/2=
010=20
2:46<BR>Para: [email protected]<BR>Asunto: [magma] Question about proxy=20
implemenation in RFC 4605<BR><BR>Hi all,<BR><BR>According to RFC 4605, a ro=
uter=20
creates a membership database after merging the subscriptions on individual=
=20
interfaces. Lets say that 3 IGMPv3 capable interfaces are as=20
follows:<BR><BR>Interface 1 has host reporting Include S1 -&gt;=20
I(S1)<BR>Interface 2 has host reporting Exclude S2 -&gt; E(0,S2)<BR>Interfa=
ce 3=20
has host reporting Exclude nothing -&gt; E(0,0)<BR><BR>For a device doing I=
GMPv3=20
proxy, the final membership record for group G is (G, EXCLUDE, NULL). Now l=
ets=20
say the host on interface 3 goes away, because of which the subscription on=
=20
interface 3 would expire and there wont be any IGMPv3 state on interface=20
3.&nbsp; How would the new membership record for PROXY be calculated?? The =
RFC=20
does not suggest any way to do this. Would IGMP process have to go through =
each=20
interface again and then recompute the new membership record?? This would b=
e=20
very inefficient especially if there are multiple interfaces.<BR>Is there a=
=20
better way to recompute the new membership=20
record??<BR><BR><BR>Thanks<BR>Kunal<BR><BR><BR><BR></FONT></P></BODY></HTML=
>

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