From: Ccie candidate (beacc1e@yahoo.com)
Date: Wed Dec 18 2002 - 13:10:43 GMT-3
Kumar,
I agree with you.
I've setup the following to test "ip multicast helper" command, but could not get the expected. (i.e host for example from R6 generated ping traffic is only getting response from the local router (R4), but could not see any traffic on the remote router R5). This is becoming really interesting.
See below.
R2(f81/0)---(e0/0)R5(s0/0.45)-----(s1.45)R4(to0)----(to0/0)R6
R2 and R6 are the hosts that does not support multicast.
R6 generates a ping traffic to 148.9.46.255.
######################
Configs of the routers
R2
..
..
interface FastEthernet8/1/0
ip address 148.9.222.1 255.255.255.0
ip directed-broadcast
no ip mroute-cache
load-interval 30
full-duplex
R5
..
..
interface Ethernet0/0
ip address 148.9.222.10 255.255.255.0
ip pim dense-mode
ip multicast helper-map broadcast 228.1.1.1 101
load-interval 30
full-duplex
interface Serial0/0.45 point-to-point
ip address 148.9.45.5 255.255.255.0
ip pim dense-mode
ip multicast helper-map 228.1.1.1 148.9.222.255 101
ip ospf message-digest-key 1 md5 cisco
frame-relay interface-dlci 504
R4
..
..
interface Serial1.45 point-to-point
ip address 148.9.45.4 255.255.255.0
ip pim dense-mode
ip multicast helper-map 228.1.1.1 148.9.46.255 101
ip ospf message-digest-key 1 md5 cisco
frame-relay interface-dlci 405
..
interface TokenRing0
ip address 148.9.46.4 255.255.255.0
ip pim dense-mode
ip multicast helper-map broadcast 228.1.1.1 101
ip ospf authentication-key cisco
ring-speed 16
R6
..
..
interface TokenRing0/0
mtu 4464
ip address 148.9.46.6 255.255.255.0
ip directed-broadcast
ip accounting access-violations
ip multicast helper-map broadcast 228.1.1.1 2001
ip ospf authentication-key cisco
ip ospf priority 2
load-interval 30
ring-speed 16
####################
R6 sends a broadcast packet in his domain.
R6#ping 148.9.46.255
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 148.9.46.255, timeout is 2 seconds:
*Mar 22 00:57:38.246: ICMP: echo reply rcvd, src 148.9.46.4, dst 148.9.46.6
But (debug ip packet / debug ip mroute ) does not show any traffic on the R5 or R2.
Anybody any idea what is missing here ?
Kafkaf
"Kumar, Senthil" <senthil.kumar@intechnology.co.uk> wrote:i am aiming for the same. but helper map doesnt seem to work..did debug ip packet to capture packets..no trace of this translation to be honest.when i have a pc with a default gateway and if i send a multicast even if the gateway is not doing a multicast routing it still receives the packet.but for it to forward it needs multicast routing (which is on), as the packet is a broadcast x.x.x.255/24 or a ff.ff.ff.ff mcast helper map can do this conversion to a multicast ip that we specify, which also means if we make a host in the multicast domain to join a group lets say 229.9.9.9and if we ask helper map to convert all broadcasts to this ip. the host should respond to the ping or atleast should receive the packet sourced from host. neither of this happens. is there a tested config with examples. not a great deal but it will be good to know..as i also thought i'd use nating but its not possible to map a /32 ip using pools a!
nd static nating is not applicable. so the solution is either tunnels or helper-map. tunnel is a bit of too much as it needs a new ip (unnumbered is not the option here)so it is upto helper map to do that job..but it doesnt seem .. the problem with cisco web site is too many repetations and its all in bits and pieces.-----Original Message-----
From: Ccie candidate [mailto:beacc1e@yahoo.com]
Sent: 18 December 2002 13:09
To: senthil.kumar@intechnology.co.uk
Cc: ccielab@groupstudy.com; SGarrett@cnitech.com; seadon@attbi.com
Subject: RE: unicast-2-multicast
Kumar,
I believe is "ip multicast helper"just to map broadcast to multicast, and vice versa via the UDP port specified by an ACL. I don't think you can use it to map a specific host address.
Does anybody has a different view of this ?
Kafkaf
-----Original Message-----
From: Kumar, Senthil [mailto:senthil.kumar@intechnology.co.uk]
Sent: Wednesday, December 18, 2002 5:08 AM
To: Don; Sean Garrett
Subject: RE: unicast-2-multicast
i did this.
three routers connected back to back. r1 is the host connected to r2
connected to r3 connected to r4.
created a tunnel between r2 and r4 and enabled pim dense mode.
the def gateway & mroute static 0.0.0.0 255.255.255.255 for r1 is r2.
r4's ethernet joined group 229.9.9.9.
r2 can reach this group via tunnel (ping 229.9.9.9 - router generates a
multicast packet in all interfaces)
r1 can't ping r4 unlesss the r2 has pim enabled on the interface connected
to r2.
did a multicast helper-map, udp forward in r2 .. no results.
wondering if the example in the cisco web explaining mulitcast helper-map
really works.
-----Original Message-----
From: Don [mailto:seadon@attbi.com]
Sent: 16 December 2002 19:54
To: Sean Garrett
Subject: Re: unicast-2-multicast
You do use a subnet on the tunnel. The problem with including the tunnel in
a routing protocol is that the protocol sees the tunnel as a route. If the
real route is also included in the same protocol, you get recursive errors
and the tunnel shuts itself down. Real life often uses static routes to get
aroung the problem, but this is usually not be allowed on the lab test. I
don't even know if static mroutes are allowed. Another method that works is
to only include one end of the tunnel in the routing protocol, but this
results in some sub-optimal routes. This is all highly dependent on what
you are trying to do with the tunnel. Having only one end included in the
routing protocol and no static routes means the tunnel is only used for
packets in that subnet only. And what use is that in an internal network?
Don
----- Original Message -----
From: "Sean Garrett" <SGarrett@cnitech.com>
To: "Don" <seadon@attbi.com>; "Kumar, Senthil"
<senthil.kumar@intechnology.co.uk>; "Abdallah Al-Suwailem"
Cc: <ccielab@groupstudy.com>
Sent: Monday, December 16, 2002 11:27 AM
Subject: RE: unicast-2-multicast
If you aren't given a subnet to use on the tunnel itself,
what should you use there? Chop up one of the /24s given
at either end to use across the tunnel?
-----Original Message-----
From: Don [mailto:seadon@attbi.com]
Sent: Monday, December 16, 2002 11:01 AM
To: Kumar, Senthil; Abdallah Al-Suwailem
Subject: Re: unicast-2-multicast
You can use a tunnel interface to get multicast across a link that only
supports unicast. Create a tunnel from one end to the other and then enable
multicast on the tunnel interfaces (and, of course, on the router interfaces
that do support multicast). This also works to load share multicast traffic
across multple links, something multicast cannot do by itself. PIM requires
all multicast interfaces to be in a unicast routing table and this can be a
problem with tunnels. If so, add a static multicast route (ip mroute
command) to fix this problem. See Doyle, Vol 2 page 596 for an example.
Don
----- Original Message -----
From: "Kumar, Senthil" <senthil.kumar@intechnology.co.uk>
To: "Abdallah Al-Suwailem" <aalsuwailem@myrealbox.com>; "Kumar, Senthil"
<senthil.kumar@intechnology.co.uk>
Cc: <ccielab@groupstudy.com>
Sent: Monday, December 16, 2002 8:21 AM
Subject: RE: unicast-2-multicast
> many thanks for your reply. but i was wondering i could could map even all
> unicasts to a host on a particular protocol and port number to convert it
> into a multicast to feed the multicast domain.. i've tried using
helper-map,
> configs look okay but couldnt figure out a method to do testing with it.
did
> permit udp any any broadcast-2-multicast-2broadcast. did forward protocol
> udp
> and enabled directed-broadcast..did a ping on the local segment x.x.x.255
> and 255.255.255.255 ..got reply from the local broadcast domain but the
> remote never replied..
>
>
>
> -----Original Message-----
> From: Abdallah Al-Suwailem [mailto:aalsuwailem@myrealbox.com]
> Sent: 16 December 2002 16:08
> To: Kumar, Senthil
> Cc: ccielab@groupstudy.com
> Subject: Re: unicast-2-multicast
>
>
>
> Hello
>
> check this command "r2(config-if)#ip multicast helper-map"
>
> r2(config-if)#ip multicast ?
> boundary Boundary for administratively scoped multicast addresses
> helper-map Broadcast to Multicast map OR Multicast to Broadcast map
> rate-limit Rate limit multicast data packets
> tagswitch Enable IP Multicast Tagswitching
> ttl-threshold TTL threshold for multicast packets
>
> Thanks
>
> Abdallah
>
> Kumar, Senthil wrote:
>
> >can nat convert all traffic on a local network, @ port xx.udp to
> mulitcast,
> >haven't got a traffic generator to test.
> >the idea is for the host on my brodcast lan to send data to multicast
> >machines hops away. my firsthop doesnt do mulitcast routing..
> >
> >any ideas, help very appreciated.
> >
> >Thanks, Senthil
> >
> >
> >
> >
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