Re: [mpls-linux-general] Re: MPLS-Linux
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Re: [mpls-linux-general] Re: MPLS-Linux
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From: James R. L. <jl...@mi...> - 2001-06-19 02:57:26
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On Tue, Jun 19, 2001 at 01:51:12AM -0000, Sunil Kumar wrote:
> Hi,
>
> I figured-out my previous problem by myself i.e Static Tunnel creation.
>
> Can you tell me that for forwarding un-labeled packets do we need to
> configure something on Linux box ? like instead of gen:16:0 gen:0:0 or
> anything like that which forwards the un-labeled packets ?
If you create just an incoming label (ie do not bind it to an outgoing label)
it will by default send the unlabeled packet to the IP stack for a route
lookup.
Example:
10.0.1.0/24 10.0.2.0/24
------- .1 .2 ----- .2 .3 -------
| LER A |-------------| LSR |----------------| LER B |
------- eth1 eth1 ----- eth2 eth1 -------
lo0 lo0 lo0
1.1.1.1/32 2.2.2.2/32 3.3.3.3/32
-------------- flow of packets ------------->
If you were setting up LER A to be an LER for packets destined to 3.3.3.3/32
You would set it up this way:
Using FEC bindings
------------------
route add -host 3.3.3.3 gw 10.0.1.2
mplsadm -A -B -O gen:3333:eth1:ipv4:10.0.1.2 -f 3.3.3.3/32
Using MPLS tunnel
-----------------
mplsadm -A -B -O gen:3333:eth1:ipv4:10.0.1.2 -T mpls0
ifconfig mpls0 1.1.1.1 pointopoint 3.3.3.3
(remember MPLS tunnel intefaces are unidirectional ... they only do TX no
RX, so you do not have to create one at the egress)
The LSR would be setup as:
mplsadm -L eth1:0
mplsadm -A -B -I gen:3333:0 -O gen:3334:eth2:ipv4:10.0.2.3
The egress LER would be setup as:
mplsadm -L eth1:0
mplsadm -A -I gen:3334:0
When packets arrive at LER B with label 3334 on any interface in labelspace
0 it will pop the label and forward the packet to the IP stack. The IP
stack will do a route look up, therefore LER B must know how to get to the
destination.
Looking at the info in /proc/net/mpls_* may be helpful to see what is
happening under the hood.
(Remember if you're using 'ping' to verify that it is working, LER B needs
to know how to get back to 1.1.1.1 and if you're going to 'route' the packet
back to 1.1.1.1, LSR will need to know how to get to 1.1.1.1 ;-)
If you're looking for even more info about what is happening under then hood
turn on MPLS kernel debugging 'mplsadm -d' then look at you kernel
log file or use the command 'dmesg' to look at the output.
Jim
> >From: "James R. Leu" <jl...@mi...>
> >Reply-To: jl...@mi...
> >To: Sunil Kumar <sun...@ho...>
> >Subject: Re: MPLS-Linux
> >Date: Mon, 18 Jun 2001 17:00:17 -0500
> >
> >Hello,
> >
> >I suggest joining the mpls-linux mailing list for future questions:
> >
> >http://lists.sourceforge.net/lists/listinfo/mpls-linux-general
> >
> >On Mon, Jun 18, 2001 at 09:36:42PM -0000, Sunil Kumar wrote:
> > > Hi,
> > >
> > > I want to creat a Manual/Static Tunnel with following topology;
> > >
> > >
> > > LER A--------------------LSR------------------LER B
> > > 172.16.10.2 172.16.10.1 172.17.10.1 172.17.10.2
> > > ETH1 ETH2
> >
> >Your diagram and the commands you've issued don't agree.
> >Describe to me what you're trying to do.
> >
> > > - LER A & B are simulated Routers so we can't configure any mplsadm
> > > command on those.
> > > - I have configured LSR as under ;
> > >
> > > mplsadm -A -O gen:1024:eth1:ipv4:172.16.10.2
> > >
> > > mplsadm -A -T mpls0
> > >
> > > ifconfig mpls0 172.17.10.2 netmask 255.255.0.0
> > >
> > > mplsadm -B -O gen:1024:eth1 -T mpls0
> > >
> > > route add -net 172.17.0.0/16 mpls0
> > >
> > > - Is there anything I did wrong in above configuration ? please advise
> >the
> > > correct command script, if the above is not correct.
> > >
> > > - How can I verify the Tunnel ID and the traffic going through it on
> > > MPLS Linux Router ? please clarify.
> >
> >Tunnel ID? Are you trying to do some sort of RSVP-TE testing using a
> >box like an Ixia or an Adtech? If so, it's not going to work.
> >MPLS-Linux is a forwarding plane. That means it only knows how to
> >"label switch" packets on established LSPs. There are two ways to establish
> >LSPs in the world of MPLS. Statically or dynamically. RSVP-TE LDP CR-LDP
> >are all means of doing dynamic LSP establishments (commonly call MPLS
> >signalling protocols). mplsadm is for setting up static LSPs manually.
> >
> >If you want to talk RSVP-TE or LDP join the mailing list and ask the
> >question there.
> >
> > > Thanks
> > > Sunil
> >
> >--
> >James R. Leu
>
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--
James R. Leu
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