Hi Darren,
the encapsulation used by "remote interface switching" CCC is (as far as
I can tell) just layer 2 in MPLS. No label stack, and nothing between
the layer 2 frame and the MPLS header. I believe the FCS is stripped
off. There's no plan AFAIK for this to be on the sandards track.
Neither is it an implementation of Juniper's Layer 2 VPN draft.
The problem with CCC is that it doesn't scale. Each CCC connection
requires 2 RSVP-signalled LSPs. This leads to an "n-squared" label
problem in the core. So while CCC is useful for tunneling
infrastructural services (e.g. Multicast, internal networks, etc.) over
an MPLS core it isn't much use, in my opinion, if you want to provide
services to customers :(
A proposed "standard" for layer 2 over MPLS encapsulation is
draft-martini-l2circuit-encap-mpls-00.txt (we are just putting 01.txt
together now.) I would expect Juniper to implement this draft.
Giles
Darren Bolding wrote:
>
> Nikolas,
>
> Thanks for your reply! I think I understand what you are saying, especially
> as regards using CCC for layer 2 switching cross-connects, or even for LSP
> stitching.
>
> However, I use the word encapsulation for a couple of reasons:
>
> (1) Its the way Juniper describes it in the only reference I can find about
> Ethernet VLAN-CCC
> (http://www.juniper.net/techpubs/software/junos42/swconfig-interfaces42/html
> /interfaces-ethernet-config8.html) which I can only find in 4.2 docs (by
> searching)
>
> (2) I'm particularly interested in MPLS LSP Tunnel Cross-Connects
> (http://www.juniper.net/techpubs/software/junos43/swconfig43-mpls-apps/html/
> ccc-config7.html#1013872). In this case, I would use encapsulation to
> describe what's happening- ingress traffic on the interface is encapsulated
> and put in an LSP, which travels across one or more LSR's to an egress point
> where it is deencapsulated (with CCC, this is largely just stuffing frames,
> but some layer-2 munging may occur).
>
> Am I missing something? I'd like to know if I misunderstand something.
>
> It seems odd that the 4.3 docs don't mention VLAN-CCC at all (that I can
> find), I presume the functionality has not been deprecated.
>
> I'm interested in finding out if the method by which layer-2 data is
> encapsulated and placed into an LSP is publicly documented, and if it is
> standards track.
>
> Greg Ketell's e-mail implies that CCC is an implementation of the MPLS
> Layer-2 VPN I-D. Which makes sense given the number of Juniper names on the
> I-D. (Thanks Greg!)
>
> --D
>
> -- Darren Bolding darren@bolding.org --
> -- http://www.bolding.org/~darren --
>
> > -----Original Message-----
> > From: Nikolas Weidenbacher [mailto:nikw@sgns.net]
> > Sent: Tuesday, January 30, 2001 4:07 PM
> > To: Darren Bolding
> > Cc: juniper-nsp@puck.nether.net
> > Subject: Re: [j-nsp] CCC encapsulation standard?
> >
> >
> >
> > Encapsulation? CCC happens within a single router, so there is no such
> > thing as a CCC packet. CCC is a configuration within the router that maps
> > two logical interfaces together, or maps a logical interface to an MPLS
> > tunnel.
> >
> > Are you sure you're not wondering about MPLS?
> >
> > Nik Weidenbacher nikw@sgns.net
> > Network Engineer 215-351-1067
> > Sungard Network Solutions
> >
> > On Tue, 30 Jan 2001, Darren Bolding wrote:
> >
> > >
> > > Hello,
> > >
> > > I'm wondering if anyone can point me to any published standards for CCC
> > > (Circuit Cross-Connect) encapsulation?
> > >
> > > I'm pretty sure its not in the ietf, but perhaps I missed it.
> > I'm wondering
> > > if Juniper has ever released the spec for interoperability purposes.
> > >
> > > Curious, and thanks,
> > >
> > > --D
> > >
> > > -- Darren Bolding darren@bolding.org --
> > > -- http://www.bolding.org/~darren --
> > >
> >
> >
> >
-- =================================================== Giles Heron - IP Architect - Level 3 Communications phone: +44 20 7864 0719 mobile: +44 7880 506185 ===================================================
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