From: Scott Morris (swm@emanon.com)
Date: Tue Nov 01 2005 - 23:39:42 GMT-3
Nbma mode has two pieces:
1. The paying attention individually to all join and leave requests. This
only has a benefit to sparse mode since there are no joins or leaves in
dense mode. If you operate in sparse-dense, you do both which means
sometimes you'll get the benefit of this feature, sometimes you won't.
2. Normally on a serial link (with two hardware queues) the IP multicast
messages are treated like "pseudobroadcasts" and placed in the broadcast
hardware queue which is a strict priority queue and process switched. This
may be great if you like your streaming stuff, but COULD mess up other
traffic and certainly cause additional strain on your router. Nbma mode
will reclassify ip multicast traffic into the normal queue. This benefit is
enjoyed whether you are using sparse or dense mode.
The code, however, in the router will bitch at you if you are running
anything other than pure sparse-only stuff. IMHO this is just a hyperactive
warning. Everything will still work as it should where it should, just the
informational message given to you by the router causes panic.
HTH,
Scott
PS. I wouldn't bother placing nbma mode on the spokes unless the direction
of traffic flow is coming OUT of one of the spokes (see #2 above).
Otherwise for incoming traffic only and not dealing with joins at all,
putting this command on the spokes would accomplish nothing. It wouldn't
hurt, it just wouldn't help anything.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Schulz, Dave
Sent: Tuesday, November 01, 2005 9:20 PM
To: Chris Lewis ; nobody@groupstudy.com; Niche
Cc: CCIEin2006 CCIEin2006 ; ccielab@groupstudy.com
Subject: RE: Does PIM dense mode or sparse-dense mode work over frame relay?
I thought that ip pim nbma-mode is suppose to solve this problem, since it
allows the multiple join messages over the frame. So, doesn't it work if
you configure ip nbma and sparse at the hub along with sparse-dense mode at
the spokes?
Dave
-----Original Message-----
From: nobody@groupstudy.com
To: Niche
Cc: CCIEin2006 CCIEin2006; ccielab@groupstudy.com
Sent: 11/1/2005 8:35 PM
Subject: Re: Does PIM dense mode or sparse-dense mode work over frame
relay?
I don't have a link offhand, some time using google will probably find one
somewhere, but I think the concept is straightforward enough to lab up and
get some experience with. Consider this.
R1---R2
|
|
R3
In this setup R1 is the hub, using a multipoint frame interface and all the
directly connected interfaces are on the same subnet.
Multicast will not normally be sent out the interface it was received on, so
that is a challenge for R2 to R3 communication. So create a tunnel between
R2 and R3 and enable ip pim dense mode on both ends. As long as you have IP
conectivity between the addresses used to create the tunnel by the IGP, you
should be able to get it to work.
Chris
Niche <jackyliu419@gmail.com> wrote:
Hi Chris,
Would you mind to provide any link to talk about this with examples?
Cheers~
Jacky
On 11/2/05, Chris Lewis <chrlewiscsco@yahoo.com> wrote:A tunnel comes to
mind
CCIEin2006 CCIEin2006 <cciein2006@yahoo.com> wrote:Great, but how do you get
dense mode (or sparse-dense mode) to work between a sender on one frame
relay spoke and a receiver on another frame relay spoke in the same subnet?
Chris Lewis <chrlewiscsco@yahoo.com> wrote: nbma-mode only makes sense for
sparse mode, there are no joins in dense.
The command reference is great at explaining things like this
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123tcr/1
23tip3r/ip3_i2gt.htm#wp1069388
Chris
cciein2006@yahoo.com wrote:
Does PIM dense mode or sparse-dense mode work over frame relay? I tried the
ip pim nbma-mode command on a multipoint frame-relay interface but it
generates an error message saying that PIM nbma-mode is not recommended for
dense mode or sparse-dense mode?
Why is this?
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