The MPLS-OPS Archive

[Eric Osborne <eosborne@cisco.com>]

On Wed, Nov 12, 2003 at 03:39:06PM +0100, Sebastien.Spas@alcatel.be wrote:
> 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).

Sure.  

> 
> 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.
> 

How is this fundamentally different from the first approach you
describe?  It seems to me to be the same thing, except for the speed
of reaction to changes.

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

There's been some IETF work in this area, I think - I'll leave this
answer to JP, since that's more his area than mine.  


eric


> 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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