Re: Carrier supporting carrier: Why not L2VPN?

Hi,

I think one way we can achieve this is to stitch two L2VPN domains with a
ASBR router , end to end L2vpn might not be possible without having a L3
to stitch Two l2vpn domains. What i mean by end-to-end L2vpn is a case
referring to a scenario of CSC or Inter-As

Regards
Rakesh M

On Fri, Jan 11, 2013 at 2:00 AM, Brian McGahan <bmcgahan_at_ine.com> wrote:

> It's the same case as like Frame Relay or ATM full mesh. If one of the
> pseudowires goes down, OSPF can heal around this with layer 3 routing using
> point-to-multipoint. If running network broadcast and your pseudowire to
> the
> OSPF DR goes down the election becomes inconsistent and you have partial
> connectivity. The second case can happen with IS-IS since it uses the DIS
> election over multipoint links. If the pseudowire can heal itself at
> layer 2
> then this is fine, but with layer 3 routing you can have partial
> connectivity
> with IS-IS in these failure scenarios.
>
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
>
> From: Routing Freak [mailto:routingfreak_at_gmail.com]
> Sent: Thursday, January 10, 2013 10:38 AM
> To: Brian McGahan
> Cc: Adam Booth; John Neiberger; ccielab_at_groupstudy.com
> Subject: Re: Carrier supporting carrier: Why not L2VPN?
>
> Brian
>
> I didnt get ur point that u r saying that
>
> "Another issue could be that if the SP buying
> transit is using IS-IS for their routing, there are some failure situations
> of
> VPLS pseudowires that IS-IS can't deal with because it doesn't have a
> point-to-multipoint behavior like OSPF does."
>
>
> Can u elaborate more on this point.
>
> I know that ISIS doesn't have point to multipoint network type unlike OSPF.
> Recently i was a part of massive implementation in ISIS with VPLS ad i dont
> see any corn cases where VPLS fails with ISIS
>
> What was the exact problem u r referring too ? Can u be a bit more
> specific.
>
> VPLS PE should be part of same Bridge Domain and r u provisioning Point to
> Multipoint LSPs which is not at all required in case of VPLS.
>
>
>
> On Mon, Dec 31, 2012 at 4:09 AM, Brian McGahan
> <bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com>> wrote:
> Cisco supports both VPLS BGP autodiscovery and H-VPLS. VPLS no doubt is
> worth
> looking at for certain applications, but for a service provider using it
> for
> long haul transport it might not be a good design option. As with anything
> there are always both pros and cons, where a major pro of VPLS is that
> it's a
> layer 2 extension as opposed to CSC which introduces more complexity in the
> layer 3 routing design, but a major con of VPLS is that it's Ethernet only.
>
> If an SP wants to use OC-192 or OC-768 POS as their long haul transport
> then
> this won't work with VPLS. Another issue could be that if the SP buying
> transit is using IS-IS for their routing, there are some failure situations
> of
> VPLS pseudowires that IS-IS can't deal with because it doesn't have a
> point-to-multipoint behavior like OSPF does.
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>>
>
> Internetwork Expert, Inc.
> http://www.INE.com
> From: Adam Booth [mailto:adam.booth_at_gmail.com<mailto:adam.booth_at_gmail.com
> >]
> Sent: Sunday, December 30, 2012 12:09 AM
> To: Brian McGahan
> Cc: John Neiberger; ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
> Subject: Re: Carrier supporting carrier: Why not L2VPN?
>
> Hi Brian,
>
> I would agree that vanilla VPLS has scaling problems compared to other
> options
> such as CSC but there are ways to enhance it to be worth looking at it.
> VPLS
> using BGP Auto Discovery should overcome the control plane scaling and
> provisioning headaches and using PBB with H-VPLS would overcome the
> forwarding
> plane scaling limitations. I'm not so sure about Cisco (and would be
> surprised if they didn't have the facility) but I know that Alcatel-Lucent
> and
> I think Juniper support these methods.
>
> Cheers,
> Adam
>
> On Sun, Dec 30, 2012 at 1:23 PM, Brian McGahan
> <bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com><mailto:bmcgahan_at_ine.com<mailto:
> bmc
> gahan_at_ine.com>>> wrote:
> It is a corner case design. Most SPs would buy lambdas on someone else's
> DWDM
> network or MPLS L2VPN etc. Routing at layer 3 through another SP
> overcomplicates the design.
>
> It's the same as like Inter-AS MPLS L3VPN option C. Just because you *can*
> do
> it doesn't mean you *should* do it.
>
> Personally I've never seen any SP run option C, and I've seen many many
> large
> implementations. I'm sure it's out there and maybe someone here on the list
> has seen it but the amount of politics and interoperability that's needed
> between the providers is the limiting factor.
>
> From a technology standpoint CSC and option C L3VPN are more scalable than
> dark fiber or DWDM or L2VPN AToM or VPLS, but from an operational point of
> view a lot of time they're just not practical.
>
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>>
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
> On Dec 29, 2012, at 8:00 PM, "John Neiberger"
> <jneiberger_at_gmail.com<mailto:jneiberger_at_gmail.com><mailto:
> jneiberger_at_gmail.co
> m<mailto:jneiberger_at_gmail.com>>> wrote:
>
> > I'm watching some videos for the SP track and I just started one on CSC
> > using L3VPN. It seems awfully complicated. I haven't even really gotten
> > into the configuration of it yet, so maybe I'll be able to answer my own
> > question shortly, but why not just use L2VPN for this? It seems like you
> > could accomplish basically the same thing with MPLS pseudowires or
> > something like that. Or maybe even VPLS or whatever. Not sure about that
> > since I haven't done VPLS yet. :-)
> >
> > So, what's the deal? What advantage does CSC via L3VPN bring that would
> > make it worth all the configuration hassle?
> >
> > Heck, why not just run MPLS over GRE?
> >
> > I'll keep watching the video and reading about it. There is probably some
> > huge advantage that I am completely missing. I'm a noob to some of this,
> so
> > go easy on me. :)
> >
> > John
> >
> >
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> Routing Freak CCIE#35889 (SPv3)
>
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