The MPLS-OPS Archive

[Sebastien.Spas@alcatel.be]

thanks.

another alternative could be to rely on network management tools to compute
the inter-area paths (net mgt tool can get global topology view through
direct discovery or OSS database), and provision the LSPs with explicit
paths (using verbatim).


I also read some papers about "route server" approach. There, a hardware or
software box will know the whole topology, maintain the gloval TE db, and
implement routnig algorithms for LSPs (SPF, CSPF, or a specific one with
another objective like load balancing).
When provisioning a new LSP, the router will contact the route server to get
the LSP path (instead of running his internal CSPF relying on the local TE
db), using a specific protocol.
The route server should be nearly as fast as local CSPF implementations, and
should allow to use dynamic paths on the router config.

Do you know anything about the state of this approach ? Is there any RFC,
protoype, or even commercial products implementing it ?

kr,
seb.

-----Original Message-----
From: Eric Osborne [mailto:eosborne@cisco.com]
Sent: mercredi 12 novembre 2003 15:21
To: Sebastien.Spas@alcatel.be
Cc: Eric Osborne; Christopher Young; Kurien Joseph; mpls-ops@mplsrc.com
Subject: Re: [MPLS-OPS]: Tunnels in multiple OSPF areas


On Wed, Nov 12, 2003 at 01:00:36PM +0100, Sebastien.Spas@alcatel.be wrote:
> Hi,
>
> can't you easily setup such tunnels across several areas using an explicit
> path ?

Yes.  It makes more sense to do so using loose ERO subobject, but as
of 12.0(26)S you can also use the 'verbatim' command to force the
headend not to check the TE DB for the existence of the hops in your
path prior to signalling.

Inter-area TE really needed two things:
	   1) loose ERO (for which verbatim is a poor, but workable,
	   substitute)

	   2) ability on the ABR to have more than one TE DB (one for
              area 0 and one for each of the other areas)

The feature I pointed to has both of those in it.



eric

>
> kr,
> seb.
>
> -----Original Message-----
> From: Eric Osborne [mailto:eosborne@cisco.com]
> Sent: mercredi 12 novembre 2003 0:07
> To: Christopher Young
> Cc: Kurien Joseph; mpls-ops@mplsrc.com
> Subject: Re: [MPLS-OPS]: Tunnels in multiple OSPF areas
>
>
> On Tue, Nov 11, 2003 at 03:49:16PM -0500, Christopher Young wrote:
> > Kurien,
> >
> > I don't believe that Traffic Engineering works across multiple OSPF
> > areas yet.
>
> it does, but it depends on code versions.
> I'm not sure offhand what's in 12.3 (from the error message, it looks
> like inter-area support isn't there), but it certainly works in 12.0S
> code.
>
>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1612/products_feature_guid
> e09186a0080080ce5.html
>
> Introduced in 12.0(19)ST1, which I think came out around November,
> 2001.  So update your competitive spreadsheet...:)
>
>
>
> eric
>
> > Thanks,
> >
> >
> > Chris Young
> > Juniper Networks
> > -----Original Message-----
> > From: Kurien Joseph [mailto:kurienjoseph@yahoo.com]
> > Sent: Tuesday, November 11, 2003 2:31 PM
> > To: mpls-ops@mplsrc.com
> > Subject: [MPLS-OPS]: Tunnels in multiple OSPF areas
> >
> >
> >
> > I have been trying to configure a tunnel across multiple OSPF area on a
> > cisco network. I have been refering to the cisco docs that talk about
> > configuration of tunnels on multiple OSPF areas.
> >
> > There was a section about configuring an Area Border router(ABR). My
> > question is if  ABR a specialized piece of hardware or software patch
> > loaded ? I have an MPLS 3600 (IOS12.3) router in the border between ospf
> > areas. Its configured as follows
> >
> > router ospf 1
> >  mpls traffic-eng router-id Loopback0
> >  mpls traffic-eng area 0
> >  log-adjacency-changes
> >  network 10.225.48.0 0.0.0.255 area 0
> >  network 10.225.50.0 0.0.0.255 area 0
> >  network 10.226.0.0 0.0.0.255 area 6
> >  network 10.226.1.0 0.0.0.255 area 6
> >  network 10.226.127.33 0.0.0.0 area 6
> >  network 10.224.0.0 0.31.255.255 area 0
> > !
> >
> >
> > Since this router is in between area 0 and 6 should I have another entry
> > as
> >
> >  mpls traffic-eng area 6
> >
> > when I do try to issue this above command, I get
> >
> > %MPLS TE already enabled, on ospf area 0
> >
> > Does that mean this router that I am using is not capable of being a ABR
> > ?
> >
> > (Cisco Docs Step 4 says I should issue the following commands.
> >
> > Router(config-router)# mpls traffic-eng area 0
> >
> > Router(config-router)# mpls traffic-eng area m
> >
> > )
> >
> > Thanks for your time.
> >
> > Kurien
> >
> >
> >
> >   _____
> >
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>
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