From: Darby Weaver (darbyweaver@yahoo.com)
Date: Thu Oct 18 2007 - 01:14:22 ART
Joe,
You are starting to scare me with those RIPv2
dreams...
But you are describing some nice little tidbits too...
Kewlicious! (my word - probably can't be used in
scrabble unless you very desperate and your friends
are illiterate anyway).
--- Joseph Brunner <joe@affirmedsystems.com> wrote:
> ip routing
>
> and learn all the sdm prefer X variables really
> really well.
>
> -Joe
>
> -----Original Message-----
> From: Alex Steer [mailto:alex.steer@eison.co.uk]
> Sent: Tuesday, October 16, 2007 3:24 PM
> To: Joseph Brunner; ccielab@groupstudy.com
> Subject: RE: ip multicast helper-map
>
> Thanks for that. I noticed the error of my ways
> just 2 minutes too
> late.
>
> Next task, learn how to turn on routing on the
> 3560... :}
>
> -----Original Message-----
> From: Joseph Brunner
> [mailto:joe@affirmedsystems.com]
> Sent: 16 October 2007 00:47
> To: Alex Steer; ccielab@groupstudy.com
> Subject: RE: ip multicast helper-map
>
> Whoa, Nellie... this close to the lab... and
> thinking of running tcp
> with
> multicast... slow down...
>
> Lets take this one together.
>
> Multicast traffic requires UDP, it's just impossible
> to syn/ack
> potentially
> thousands of sessions from the GDA (group
> destination address) initial
> syn...
>
> Imagine that you send a SYN, and say, 3,900 people
> send back a SYN/ACK.
> Holy
>
> Drunk hipster chick on your couch while your wife's
> a on a business trip
> batman!
>
> Now, that we agree that its going to be UDP, so no
> one has to send back
> anything, good, lets continue.
>
> Multicast is mostly one way traffic. The sources
> register with the RP,
> and
> then they start down the source tree after spt
> switchover. Many many
> packets
> flow from the source towards the destination GDA
> with only a few PIM
> packets
> back. So as long as PIM keeps telling the source it
> wants traffic the
> S,G
> tree will keep flowing... I am at an office where
> the feed has been
> going
> for 13 Months, non-stop! Cool huh...
>
> So lets talk about this command. In the days of wall
> street (I mean 1987
> like the movie) these bad boy tandem computers like
> to send out stock
> quotes
> on a 255.255.255.255 udp broadcast to a developer
> determined port #. Now
> a
> few years later Cisco and their engineers came along
> and have to route
> this
> local broadcast traffic towards other parts of the
> network over t-1
> lines
> and such, where udp broadcast is not allowed. So the
> command does two
> things-
>
> Convert a broadcast to a multicast (usually facing
> the lan where the
> broadcast is going on)
>
> Then... at the end...
>
> Convert a multicast to a broadcast (usually facing
> the lan where we want
> to
> send the broadcast back as a directed broadcast)
>
> VPN_1(config-if)#ip multicast helper-map ?
> A.B.C.D IP multicast address
> broadcast Broadcast address
>
> I have seen this used to convert a multicast to a
> directed broadcast and
> then back to a multicast...
>
> Its used with UDP traffic and the "ip
> forward-protocol udp XXXX" is used
> to
> make sure the traffic is processed switched, a
> requirement for
> conversion...
>
> Another cool trick is to convert unicast to a
> multicast... for this I
> run
> "Ip nat outside", where we nat destination udp
> unicast address to a
> multicast GDA, and dump it on the lan... cool huh?
>
> Check out the doc cd very very carefully on how to
> implement this bad
> boy...
>
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hi
> mc_r
> /mlt_i1h.htm#wp1134745
>
> If you get this on a lab, you should know all
> intricacies of this,
> including
> remembering that you MUST configure ip
> directed-broadcast to allow the
> conversion to finish back to broadcast at the
> receiving end.
>
> So print it out, love it, learn it, take it with you
> in your dreams...
> (I
> had a rip v2 dream the other night... scary huh?)
>
> -Joe
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> Alex
> Steer
> Sent: Monday, October 15, 2007 3:13 PM
> To: ccielab@groupstudy.com
> Subject: ip multicast helper-map
>
> Hi,
>
>
>
> I'm having trouble with this, can anyone help me
> please.
>
>
>
> I have 2 routers separated by a ppp link, I'm not
> saying it definitely
> doesn't work but to be honest I just don't know.
> Can any suggest a good
> way to troubleshoot this? Is it worth adding TCP to
> the access-lists
> and telnetting to port 5575?
>
>
>
> Here are the configs...
>
> I've added show ip mroute output at the bottom
> though again is this even
> any use in this scenario (Incoming interface: Null)?
>
>
>
> As always, thank you in advance
>
>
>
> Alex
>
>
>
> ================First hop router====================
>
> ip multicast-routing
>
> ip forward-protocol udp 5575
>
> ip access-list extended helper-map
>
> permit udp any host 255.255.255.255 eq 5575
>
>
>
>
>
> interface Ethernet1/0
>
> ip address 129.1.3.133 255.255.255.128
>
> ip pim dense-mode
>
> ip multicast helper-map broadcast 233.33.33.33
> helper-map
>
>
>
> interface Serial1/1
>
> ip address 129.1.23.3 255.255.255.0
>
> ip pim neighbor-filter pimfilter
>
> ip pim dense-mode
>
>
>
> Outgoing interface flags: H - Hardware switched, A -
> Assert winner
>
> Timers: Uptime/Expires
>
> Interface state: Interface, Next-Hop or VCD,
> State/Mode
>
>
>
> (*, 239.1.0.1), 00:37:52/00:02:02, RP 0.0.0.0,
> flags: DC
>
> Incoming interface: Null, RPF nbr 0.0.0.0
>
> Outgoing interface list:
>
> Serial1/1, Forward/Dense, 00:37:52/00:00:00
>
> Serial1/0, Forward/Dense, 00:37:52/00:00:00
>
>
>
> (*, 224.0.1.40), 01:54:10/00:02:44, RP 0.0.0.0,
> flags: DCL
>
> Incoming interface: Null, RPF nbr 0.0.0.0
>
> Outgoing interface list:
>
> Serial1/1, Forward/Dense, 00:39:53/00:00:00
>
> Ethernet0/0, Forward/Dense, 01:54:11/00:00:00
>
> Serial1/0, Forward/Dense, 01:53:39/00:00:00
>
>
>
>
>
> Last hop router.
>
> ip multicast-routing
>
> ip forward-protocol udp 5575
>
>
>
> ip access-list extended source
>
> permit udp 129.1.3.128 0.0.0.127 any eq 5575
>
>
>
> interface FastEthernet0
>
> ip address 129.1.17.1 255.255.255.0
>
> ip directed-broadcast
>
> ip pim dense-mode
>
>
>
> interface Serial1
>
> ip address 129.1.13.1 255.255.255.0
>
> ip pim dense-mode
>
> ip multicast helper-map 233.33.33.33 129.1.17.255
> source
>
> encapsulation ppp
>
>
>
> (*, 233.33.33.33), 00:30:05/stopped, RP 0.0.0.0,
> flags: DCL
>
> Incoming interface: Null, RPF nbr 0.0.0.0
>
> Outgoing interface list:
>
> Serial1, Forward/Dense, 00:30:05/00:00:00
>
>
>
> (*, 224.0.1.40), 01:54:17/00:02:32, RP 0.0.0.0,
> flags: DCL
>
> Incoming interface: Null, RPF nbr 0.0.0.0
>
> Outgoing interface list:
>
> FastEthernet0, Forward/Dense, 01:54:17/00:00:00
>
> Serial1, Forward/Dense, 01:54:12/00:00:00
>
>
>
>
>
>
>
>
>
>
>
This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:15 ART