The MPLS-OPS Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] RE: Tunnels in multiple OSPF areas
Hi, At 05:10 PM 11/12/2003 +0100, Sebastien.Spas@alcatel.be wrote: >main difference is : > >-first approach I mentionned is available today in commercial tools, and can >even by developped through scripting layer, or by operators themselves. It's >basically building the path off-line (no time constraint), and translating >it into CLI command sent to the router afterwards. Like provisioning tools >available today. Result will be rather static routers, and route changes >always trigerred by the operator. >Implementation can be dedicated software tool, or extension to existing ones >or OSS. > >-second approach is more dynamic. it's transparent to the operator, requires >extention on the routers, and would allow dynamic path recomputing trigered >on the router by timer or autobandwidth like behaviors. This can't be made >easily available today. >Implementation will be new software or hardware box. > This is a bit simplistic summary ... If you are interested, you can read draft-vasseur-inter-AS-TE-010.txt. Note that a new draft will be posted for ITEF-59 covering both the inter-area and inter-AS cases but in the two cases a method making use of distributed Path Computation Element can be used to compute the shortest path end to end of TE LSPs spanning multiple areas/ASes (while being able to compute diversely routed paths, getting equivalent call set up failure as with a single area, ...). JP. >-----Original Message----- >From: Eric Osborne [mailto:eosborne@cisco.com] >Sent: mercredi 12 novembre 2003 16:41 >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 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 > > > > > > > > > > > > > > > > _____ > > > > > > > > Do you Yahoo!? > > > > Protect <http://antispam.yahoo.com/whatsnewfree> your identity with > > > > Yahoo! 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