From: cebuano (cebu2ccie@cox.net)
Date: Mon Mar 17 2003 - 13:04:24 GMT-3
Jim,
I just saw this summation on MVR from the CNAP book Multilayer Switching
Companion Guide page 469...
Some of the advantages of MVR are as follows:
1. MVR reduces each multicast group to a single data stream on the
backbone regardless of the number of users or VLANs.
2. MVR scales with the number of multicast groups, not with the number
of subscribers.
3. MVR speeds up joins and leaves, because they are done locally.
4. MVR can limit the number of multicast sessions per port.
5. MVR relies on a single multicast VLAN to be shared in the network
while subscribers remain in separate VLANs.
6. MVR provides the ability to continuously send multicast streams in
the multicast VLAN but to isolate the streams from the subscriber VLANs
for bandwidth and security reasons.
What I am understanding from this is that without MVR, the
switches/routers would have to create separate streams for hosts that
want to join a multicast group if the hosts are in separate VLANs. MVR
thus minimizes overhead by having only ONE multicast stream regardless
of which VLANs the join messages are originating.
Again, you likely have studied multicast in more detail than me so I
hope this summary answers some of your own questions. If you can
summarize your understanding of this topic after reading this, please
share your thoughts.
Elmer
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Sunday, March 16, 2003 10:31 PM
To: Group Study; David Porta
Subject: Re: Normal multicast switching behavior versus MVR
Hey David,
I did indeed read through the free IPExpert tutorial on the 3550 and as
incredible as this may sound, the write up on MVR was taken word for
word
from the 3550 config guide. Hard to believe isn't it?
In any case, what I've been trying to understand is how MVR alters the
normal switch behavior for multicast traffic. Earlier today I posted a
note
where I described normal multicast switching behavior that I got from
Beau
Williamson book, Developing IP Multicast Networks. BTW, it's an
excellent
book if you really want to understand multicast.
What's bothering me, is that I can't understand how MVR is different or
better than the way multicast traffic is normally handled. The way I
understand it, normally when mcast traffic comes into a switch from a
router
on it's way to a recipient host, the switch either using igmp snooping
or
cgmp adds the port of the host that wants mcast traffic to an entry in
the
cam table for that mcast group. It does this so that mcast traffic
isn't
flooded to any other ports in the vlan that don't want to receive it.
The only difference I can discern is that with MVR, the mcast traffic
comes
into switch on a separate vlan from that of the receiving host. But, so
what?
I'm started to wonder if the real function of this feature is just
marketing
hype. What do you think?
Jim
----- Original Message -----
From: "David Porta" <David.Porta003@msd.govt.nz>
To: "Erling Bjontegard" <erli-b@online.no>
Cc: "ccie2be" <ccie2be@nyc.rr.com>; <ccielab@groupstudy.com>
Sent: Sunday, March 16, 2003 7:09 PM
Subject: Re: MVR
> Hi Jim,
>
> Also, I believe you said you were going to purchase the latest
IPExpert
> workbook. If you did, in the first page of Chapter 2, you will find
the
> URL for the free 3550 tutorial. This tutorial has a section for MVR.
>
> Cheers,
>
> David
>
> >
> > Hi Jim,
> > there is some info about MVR in the doc. for the Catalyst 3550.
> >
http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12113ea1/3550s
cg/s
wigmp.htm#wp1061365
> >
> > Best Regards
> > Erling Bjontegard
> >
> > ----- Original Message -----
> > From: "ccie2be" <ccie2be@nyc.rr.com>
> > To: "Group Study" <ccielab@groupstudy.com>
> > Sent: Sunday, March 16, 2003 6:54 PM
> > Subject: MVR
> >
> > > Hi,
> > >
> > > Is there any white paper or good source of info on MVR, Multicast
Vlan
> > > Registration?
> > >
> > > I can't find anything.
> > >
> > > Jim
>
> -------------------------------
> This email message and any attachment(s) is intended only for the
> person(s) or entity(entities) to whom it is addressed. The
> information it contains may be classified as IN CONFIDENCE and may be
> legally privileged. If you are not the intended recipient any use,
> disclosure or copying of the message or attachment(s) is strictly
> prohibited. If you have received this message in error please
> notify us immediately and destroy it and any attachment(s).
> Thank you. The Ministry of Social Development accepts no
> responsibility for changes made to this message or to any
> attachment(s) after transmission from the Ministry.
> -------------------------------
This archive was generated by hypermail 2.1.4 : Sat Apr 05 2003 - 08:51:41 GMT-3