From: Keane, James (James.Keane@agriculture.gov.ie)
Date: Tue Dec 07 2004 - 09:18:40 GMT-3
OK A Recap
==========================================================================================
From CiscoPress - OSPF Network Design Solutions SE - Thomas M Thomas II CCIE 9360
Pg 132
Cisco routers do not support LSA Type 6 Multicast OSPF (MOSPF)
They generate syslog messages if they receive such packets. If a router is receiving many MOSPF
packets, you might want to configure the router to igore the packets and thus prevent a large
number of syslog messages. To do so, use the following command in router configuration mode:
router ospf 109
ignore lsa mospf
pg 714-715
RFC 1585: MOSPF: Analysis and Experience
... the basic operation of MPSOF and how it users IGMP to monitor multicast group membership. This information is retrieved from the
LAN and then forwarded out by the router by the OSPF flooding protocol through the use of the new group-membership LSA.
offically- Cisco routers do not currently support MOSPF because of scaling issues .... they prefer PIM
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http://www.ietf.org/rfc/rfc1584.txt
http://www.ietf.org/rfc/rfc1585.txt
Now I am attempting to get me head around all this
For the purposes of the lab (i havent done it yet so I cant break NDA) - i'd imagine imagine they arent going to go into all this detail about MOSPF ..
if they (hypotecially) asked how do you prevent MOSPF packets from disrupting the network or causing disruption on the netowrk
ignore lsa mospf will do the trick
otherwise you have to prevent to routers talking OSPF altogether to prevent this LSA from propogating INTRA-AREA
INTERAREA you might be able to screw about with NSSA etc to block the propogation of this type
BUT remember we are talking about NONCISCO routers here ....
so you would have to block all of ospf with your noncisco router.
would cisco really want us to do all this research into a protocol they are attempting get rid of ? (sorry Steve Deering)
Anyway I am confident I know enough about MOSPF now ...
James Keane
-----Original Message-----
From: Roberto Adjakou [mailto:radjakou@cfao.sn]
Sent: 07 December 2004 11:35
To: Lee Donald; Howard C. Berkowitz; ccielab@groupstudy.com
Subject: RE: Block MOSPF LSA
OK.
Please confirm that the MCast adress will be 224.0.0.1.
-----Message d'origine-----
De : Lee Donald [mailto:Lee.Donald@t-systems.co.uk]
Envoyi : mardi 7 dicembre 2004 11:16
@ : Roberto Adjakou; Lee Donald; Howard C. Berkowitz; ccielab@groupstudy.com
Objet : RE: Block MOSPF LSA
Would it not be better to use a multicast access list ?
-----Original Message-----
From: Roberto Adjakou [mailto:radjakou@cfao.sn]
Sent: 07 December 2004 11:17
To: Lee Donald; Howard C. Berkowitz; ccielab@groupstudy.com
Subject: RE: Block MOSPF LSA
Change net type and neighbor.
-----Message d'origine-----
De : Lee Donald [mailto:Lee.Donald@t-systems.co.uk]
Envoyi : mardi 7 dicembre 2004 11:10
@ : Roberto Adjakou; Howard C. Berkowitz; ccielab@groupstudy.com
Objet : RE: Block MOSPF LSA
Won't that block all Multicasts? How will your neighbours form ?
-----Original Message-----
From: Roberto Adjakou [mailto:radjakou@cfao.sn]
Sent: 07 December 2004 11:10
To: Howard C. Berkowitz; ccielab@groupstudy.com
Subject: RE: Block MOSPF LSA
"Ignore lsa mospf" is not the issue. This command does not block MOSPF LSA.
U can block all lsa flooding. As Cisco routers do not accept MOSPF packets,
I think they don't generate it. So this is not the correct answer.
U can block multicast traffic from the switch's port on which is connected
the router. Think of "switchport block multicast".
I don't know if I am correct but I'll do this task that way.
-----Message d'origine-----
De : Howard C. Berkowitz [mailto:hcb@gettcomm.com]
Envoyi : samedi 4 dicembre 2004 17:17
@ : ccielab@groupstudy.com
Objet : Re: Block MOSPF LSA
At 9:47 AM +0000 12/3/04, Georg Pauwen wrote:
>Hello group,
>
>I have searched the archives extensively for a conclusive answer to
>the requirement of blocking MOSPF LSAs, but besides the command
>ignore lsa mospf, I could not find anything. Since that command.
>Since that command only suppresses sending of syslog messages when
>the router receives
>MOSPF packets, and does not filter MOSPF packets themselves, how do
>I actually block these packets ?
>
>Regards,
>
>Georg
Is this an actual problem? There are very few, if any,
implementations of MOSPF, so where are the LSA's coming from? The
last production version I knew of was at NASA with Proteon routers.
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