From: Roman Rodichev (roman@iementor.com)
Date: Wed Nov 26 2008 - 11:58:17 ARST
Ok smarty pants :) I should note I didn't say that command was MDT specific.
I was providing a basic explanation of TE breaking multicast. MDT falls
under that.
Roman Rodichev
5xCCIE #7927 (R&S, Security, Voice, Storage, Service Provider)
Instructor, Content Developer
ieMentor Corporation http://www.iementor.com
Y!M: roman7927
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Jian
Gu
Sent: Wednesday, November 26, 2008 1:21 AM
To: Roman Rodichev
Cc: Vin Mendoza (vinm); mreiks; Cisco certification; Cisco certification
Subject: Re: MPLS TE + RSVP+LDP
Roman,
The command "mpls traffic-eng multicast intact" was introduced* *to enable
interoperability between* *Protocol-Independent Multicast (PIM) and
Multiprotocol Label Switching (MPLS) traffic engineering, it has nothing to
do with MDT RPF check, it is introduced before mVPN is available.
There are 3 RPF check happens in mVPN, 1) C-packets received from a PE
router customer interface in mVRF; 2) P-ackets received from a PE router or
P router interface in the global routing table; and 3)C-Packets received
from MTI (multicast tunnel interface) in mVRF
RPF check 1) is straightforwad.
For RPF check 2), if MPLS TE tunnel is next hop between PEs, yes, you will
need this command to make RPF check pass, but note that it is not a
necessity to have MPLS TE tunnel as IGP next hop between PEs, in fact, the
whole mVPN does not depend on MPLS at all (only PIM SM register/register
stop messages will ride on existing MPLS transport)
For 3) IOS has internally changed the RPF check requirements such that if
MBGP has learned a prefix that contains C-source address, the RPF inteface
is set to MTI that is associated with that mVRF and RPF neighbor is also
modified to be the remote PE router,
So you see, MDT has nothing to do with "mpls traffic-eng multicast intact".
Jian
P.S. I highly doubt that OP is doing MDT though.
On Tue, Nov 25, 2008 at 7:41 PM, Roman Rodichev <roman@iementor.com> wrote:
> When a multicast IP packet is received, IOS will perform RPF check on the
> source of the multicast packet to make sure it arrived on the correct
> interface. MDT tunnels are sourced from loopback interfaces, same
loopbacks
> that are reachable via the TE tunnels. MDT tunnel packets destination is
> multicast. So when a PE receives an MDT packet on a physical interface, it
> does an RPF check and says "Oh, this source is supposed to arrive on this
> TE
> tunnel interface" and multicast breaks. That command fixes the problem
>
>
> Roman Rodichev
> 5xCCIE #7927 (R&S, Security, Voice, Storage, Service Provider)
> Instructor, Content Developer
> ieMentor Corporation http://www.iementor.com
> Y!M: roman7927
>
>
> -----Original Message-----
> From: Vin Mendoza (vinm) [mailto:vinm@cisco.com]
> Sent: Tuesday, November 25, 2008 9:37 PM
> To: Roman Rodichev; mreiks
> Cc: Cisco certification; Cisco certification
> Subject: RE: MPLS TE + RSVP+LDP
>
> What does multicast-intact do?
>
> Vin
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Roman Rodichev
> Sent: Tuesday, November 25, 2008 10:20 PM
> To: 'mreiks'
> Cc: 'Cisco certification'; 'Cisco certification'
> Subject: RE: MPLS TE + RSVP+LDP
>
> You are doing MDT?
>
>
>
> under router ospf or router isis in the core put:
>
>
>
> mpls traffic-eng multicast-intact
>
>
>
>
>
>
>
>
>
> Roman Rodichev
>
> 5xCCIE #7927 (R&S, Security, Voice, Storage, Service Provider)
>
> Instructor, Content Developer
>
> ieMentor Corporation http://www.iementor.com
>
> Y!M: roman7927
>
>
>
> From: mreiks [mailto:marakalas.molefe@gmail.com]
> Sent: Tuesday, November 25, 2008 9:15 PM
> To: Roman Rodichev
> Cc: Cisco certification; Cisco certification
> Subject: Re: MPLS TE + RSVP+LDP
>
>
>
> Hmm, my excitement was short-lived there. Now my multicast tunnel
> between the two PE routers is broken after disabling "mpls ip" on the
> interfaces.
> Any idea?
>
> On Wed, Nov 26, 2008 at 5:12 AM, mreiks <marakalas.molefe@gmail.com>
> wrote:
>
> Wow, tx a lot Roman, it's working now without "mpls ip" on the SP
> interfaces. I only had the TE tunnel configured only on the one PE. Much
> appreciated.
>
>
>
> On Wed, Nov 26, 2008 at 4:38 AM, Roman Rodichev <roman@iementor.com>
> wrote:
>
> Hello,
>
> You don't need LDP in order to run MPLS VPN over TE tunnels. When you
> say you "disable LDP on the interfaces", I assume you are disabling
> "mpls ip" on the physical interfaces. In a simple CE1 - PE1 - P - PE2 -
> CE2 network, make sure you have a TE tunnel from PE1 to PE2 and from PE2
> to PE1. Make sure you are using "tunnel mpls traff autoroute announce"
> so that PE1 and PE2 loopbacks are reachable via TE tunnels instead of
> the IGP path. You can remove LDP between PE1, P and PE2 router, and your
> MPLS L3VPN will work.
>
> By the way, you don't need "mpls ip" on the TE tunnel interfaces if
> their headends and tailends are on PE routers (not on P routers).
>
> If you have a specific scenario, please present.
>
> Roman Rodichev
> 5xCCIE #7927 (R&S, Security, Voice, Storage, Service Provider)
> Instructor, Content Developer ieMentor Corporation
> http://www.iementor.com
> Y!M: roman7927
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> mreiks
> Sent: Tuesday, November 25, 2008 2:37 PM
> To: Cisco certification; Cisco certification
> Subject: MPLS TE + RSVP+LDP
>
> Hi
>
> I am finding it diffucult to understand whether RSVP TE can be run
> instead of LDP/TDP. I am able to establish the tunnel with TE but when I
> disable LDP on the interfaces, my VPN sites cannot ping each other,
> until such time I enable LDP. Is this normal? With MPLS VPNs do we
> always have to run either LDP/TDP and have RSVP also if we want TE?
>
> Tx.
>
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _____________________________________________________________________
> Subscription information: http://www.groupstudy.com/list/comserv.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Mon Dec 01 2008 - 08:18:32 ARST