Re: [CCAMP] Overlay model framework and context
Iftekhar Hussain <IHussain@infinera.com> Tue, 25 December 2012 00:08 UTC
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From: Iftekhar Hussain <IHussain@infinera.com>
To: Lou Berger <lberger@labn.net>, Daniele Ceccarelli <daniele.ceccarelli@ericsson.com>
Thread-Topic: [CCAMP] Overlay model framework and context
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Date: Tue, 25 Dec 2012 00:08:41 +0000
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Cc: CCAMP <ccamp@ietf.org>
Subject: Re: [CCAMP] Overlay model framework and context
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Agree with the comments about reusing some of the L3VPN like terminology. Unless the existing terminology PE/CE does not suffice, reusing the existing terminology will be less confusing. BR, Iftekhar -----Original Message----- From: Lou Berger [mailto:lberger@labn.net] Sent: Wednesday, December 19, 2012 7:09 AM To: Daniele Ceccarelli Cc: CCAMP Subject: Re: [CCAMP] Overlay model framework and context Daniele, see below. On 12/19/2012 5:56 AM, Daniele Ceccarelli wrote: > Hi Lou, > > Plese find replies in line. > > BR > Daniele > >> -----Original Message----- >> From: Lou Berger [mailto:lberger@labn.net] >> Sent: lunedì 17 dicembre 2012 20.45 >> To: Daniele Ceccarelli >> Cc: CCAMP >> Subject: Re: [CCAMP] Overlay model framework and context >> >> >> Daniele, >> Thanks for getting this on-list discussion going. I have some >> comments and questions: >> >> - So what's a "client layer network" in this context? Perhaps you >> mean OC or "(overlay) customer layer"? > > Yes. The terms client layer and server layer are reminescences to be corrected. > >> >> - So what's a "server layer network" in this context? Perhaps you >> mean OE or "(overlay) provider layer"? > > Again correct > >> >> - For OC, I'd thing referring back to a CE in the VPN context, and >> likewise to a PE for an OE, is helpful context. > > In the case of the interface we generally define the ONI as an overlay > interface that in a particular case is called UNI. I have no idea what this means. I suspect it relates to comments below, so will discuss there. > I would > apply the same method: those nodes are called Overlay Customer and > Overlay Edge and in the particular case of VPNs they are the CE and PE > respectively. What about that? > How about: An OC is analogous to an L3VPN CE, and an OE is analogous to an L3VPN PE (with a provider based VPN). >> >> - As you mention in the Appendix, (from the OC perspective) there is >> no difference between a virtual and real node (and presumably link as >> well). Given this and your comment in 8, that the ONI can take the >> form of a UNI or include both signaling and routing (i.e., a >> peer/I-NNI or >> E-NNI) what value is there in introducing the ONI term? Said another >> way, there's no specific term for the interface between a CE and PE >> in L3VPNs, so why do we need to introduce one in this context? > > We gave a name to the UNI, why don't giving to the ONI? Because redundant/unnecessary terminology only obfuscates. Why not customer interface/link? This has been sufficient for L3VPNs. > >> >> I think this same comment probably holds for the O-NNI (e.g., what's >> the name of the interface between providers which support L3VPN >> handoffs?)... > > I would suggest giving a name to that interface also in order to distinguish between an "internal" and an "external" link when multiple overlay provider network domains are present. > How about inter-provider interface/link? Again, this has been sufficient for L3VPNs. Lou >> >> Much thanks, >> Lou >> >> On 12/17/2012 6:17 AM, Daniele Ceccarelli wrote: >>> Dear CCAMPers, >>> >>> In the last weeks several off-line discussions on the >> Overlay model framework and related works took place. Some >> discussions led to some sort of agreemet among a small group of >> people, some others to a set a viable options, some others to totally >> open issues. I tried to summarize the output of such discussions >> below so to progress the discussions into a single thread on the WG >> ML. >>> >>> Please note that the aim of this mail is not to present a >> well shaped and conclusive idea to the WG but rather to provide the >> basis for starting a discussion from a barely shaped idea (step 1) >> instead of starting it from scratch (step 0). >>> >>> In addition you can find attached a slide depicting a >> proposal of the overlay scenario. >>> >>> Thanks, >>> Daniele >>> >>> + Disclaimer: >>> 1. Packet opto integration is often considered but the work >> can be extented to any type of SC. Eg. TDM over LSC. >>> >>> + Terminology: >>> >>> 1. Virtual Link: A virtual link is a potential path between >> two virtual or real network elements in a client layer network that >> is maintained/controlled in and by the server domain control plane >> (and as such cannot transport any traffic/data and protected from >> being de-provisioned) and which can be instantiated in the data plane >> (and then can carry/transport/forward traffic/data) preserving >> previously advertised attributes such as fate sharing information. >>> 2. Virtual Node: Virtual node is a collection of zero or >> more server network domain nodes that are collectively represented >> to the clients as a single node that exists in the client layer >> network and is capable of terminating of access, inter-domain and >> virtual links. >>> 3.Virtual Topology: Virtual topology is a collection of one >> or more virtual or real server network domain nodes that exist in the >> client layer network and are interconnected via 0 or more virtual >> links. >>> 4. Overlay topology: is a superset of virtual topologies >> provided by each of server network domains, access and inter-domain >> links. >>> 5. Access Link: Link between OC and OE. GMPLS runs on that >> link. It can support any of the SCs supported by the GMPLS. >>> 6. Overlay Customer (OC): Something like the CN in RFC4208 >> teminology but (i) receiving virtual topology from the core network >> and requesting the set up of one of them or (ii) requesting the >> computation and establishment of a path accordingly to gien >> constraints in the core network and receiving the parameters >> characterizing such path. (ii) == UNI. >>> 7. Overlay Edge (OE): Something like the EN in RFC4208 but >> able to deal with (i) and (ii) above. >>> 8. ONI : Overlay network interface: Interface allowing for >> signaling and routing messages exchange between Overlay and Core >>network. Routing information consists on virtual topology >>advertisement. When there is no routing adjacency across the >>interface it is equivalent to the GMPLS UNI defined in 4208. >> Signaling messages are compliant with RFC4208. Information related >>to path carachteristics, e.g. TE-metrics, collected SRLG, path delay >>etc, either passed from OE to OC via signaling after the LSP >>establishment in the core network or from OC to OE to be used as path >>computation constraints, fall under the definition of signaling info >>and not routing info). >>> 9. O-NNI (name to be found,maybe reused): Interface on the >> links between different core networks in the overlay model >> environment, i.e. Between border OEs. Same features of the ONI apply >> to this interface. Could it be an E-NNI? A ONI? A new name is needed? >>> >>> + Statements >>> 1. In the context of overlay model we are aiming to build >> an overlay >>> topology for the client network domains 2. The overlay >> topology is comprised of: >>> a) access links (links connecting client NEs to the >> server network domains). They can be PSC or LSC. >>> b) inter-domain links (links interconnecting server >> network domains) >>> c) virtual topology provided by the server network >> domains. Virtual Links + Virtual Nodes (TBD) + Connectivity Matrix >> (with a set of parameters e.g. SRLG, optical impairments, delay etc >> for each entry) describing connectivity between access links and >> virtual links. >>> 3. In the context of overlay model we manage hierarchy of overlay >>> topologies with overlay/underlay relationships 4. In the context of >>> overlay model multi-layering and inter-layer relationships >> are peripheral at best, it is all about horizontal network >> integration 5. The overlay model assumes one instance for the client >> network and a separate instance for the server network and in the ONI >> case the server network also surreptitiously participates in the >> client network by injecting virtual topology information into it. >>> 6. L1VPN (and LxVPN) in general is a service provided over >> the ONI (it falls under the UNI case as no routing adjacency is in >> place between OC and OE). >>> >>> + Open issues/questions >>> >>> 1. PCE-PCEP - do we need to include considerations about >> PCE and PCEP into the overlay framework context? >>> 2. BGP-LS needs to be considered >>> 3. Should potentials be included? E.g. I2RS? >>> >>> + Appendix: >>> Some notes on the Virtual Node: >>> 1. Virtual Link Model along, sadly, does not scale >> because of N**2 problem. IP over ATM and single-segment PWs have the >> same issue, that's why people invented multi-segment PWs >>> 2. The only way to avoid full-mesh of Virtual Links is >> by having intermediate nodes interconnecting Virtual Links in the >> middle of the virtual topology >>> 3. These intermediate nodes cannot be real server >> domain switches, because, generally speaking: >>> a)Real switches belong to different layer network; >>> b)Real switches are named from different naming space >>> c)real switches individually may not have sufficient >> resources to terminate virtual links (while a group of real switches >> collectively will have) >>> d)Presenting a group of real switches as a single virtual >> node have better scalability qualities >>> 4. Even if you map a virtual node on a single real >> node, you need to keep in mind that real server domain switches are, >> generally speaking, blocking switches and as such must expose their >> connectivity matrices >>> 5. If you want to compute SRLG-disjoint paths that >> could potentially go through a real server domain switch, the >> latter's connectivity matrix must expose "internal" SRLGs, so that >> the two services traversing the switch will not simultaneously fail >> if a single internal element shared by the services fails >>> 6. If you walk through all cases that need to be >> addressed when you are traffic engineering topologies with blocking >> switches, you will understand that there is absolutely no difference >> between a virtual node and real blocking real node. >>> 7. Even in case of pure VL model, client NEs connected >> to server network domain must be upgraded so that they could >> understand the connectivity matrices advertised by the border nodes >> describing connectivity constraints between access links and virtual >> links they terminate. >>> >>> >>> >>> =================================== >>> DANIELE CECCARELLI >>> System & Technology - PDU Optical & Metro >>> >>> Via E.Melen, 77 >>> Genova, Italy >>> Phone +390106002512 >>> Mobile +393346725750 >>> daniele.ceccarelli@ericsson.com >>> www.ericsson.com >>> >>> This Communication is Confidential. We only send and receive >> email on >>> the basis of the term set out at www.ericsson.com/email_disclaimer >>> >>> >>> >>> _______________________________________________ >>> CCAMP mailing list >>> CCAMP@ietf.org >>> https://www.ietf.org/mailman/listinfo/ccamp >>> >> > > >
- Re: [CCAMP] Overlay model framework and context Gert Grammel
- [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Gert Grammel
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Gert Grammel
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- [CCAMP] R: Overlay model framework and context BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] R: Overlay model framework and context Lou Berger
- [CCAMP] R: R: Overlay model framework and context BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] R: Overlay model framework and context Daniele Ceccarelli
- [CCAMP] R: R: Overlay model framework and context BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Lou Berger
- [CCAMP] 答复: Overlay model framework and context Fatai Zhang
- [CCAMP] 答复: R: R: Overlay model framework and con… Fatai Zhang
- [CCAMP] R: Overlay model framework and context BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] R: R: Overlay model framework and con… Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli
- Re: [CCAMP] Overlay model framework and context Lou Berger
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- [CCAMP] R: R: R: Overlay model framework and cont… BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] R: R: Overlay model framework and con… Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] R: R: Overlay model framework and con… John E Drake
- Re: [CCAMP] R: R: Overlay model framework and con… Igor Bryskin
- Re: [CCAMP] R: R: Overlay model framework and con… John E Drake
- Re: [CCAMP] R: R: Overlay model framework and con… Igor Bryskin
- Re: [CCAMP] R: R: Overlay model framework and con… John E Drake
- Re: [CCAMP] R: R: Overlay model framework and con… Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context John E Drake
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- [CCAMP] R: R: R: Overlay model framework and cont… BELOTTI, SERGIO (SERGIO)
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Iftekhar Hussain
- Re: [CCAMP] Overlay model framework and context Iftekhar Hussain
- Re: [CCAMP] Overlay model framework and context Iftekhar Hussain
- Re: [CCAMP] Overlay model framework and context Gert Grammel
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Igor Bryskin
- Re: [CCAMP] Overlay model framework and context Snigdho Bardalai
- Re: [CCAMP] Overlay model framework and context Gert Grammel
- Re: [CCAMP] Overlay model framework and context Daniele Ceccarelli