The MPLS WG Archive

[Spice Sylvia <falsesylvia@yahoo.co.uk>]

May I be bold enough to ask the reason MPLS was ever
deployed?

some more queries inline.>

--- Marc Binderberger <marc@sniff.de> wrote:

> Hello,
> 
> > With MPLS I can create MPLS VPNs, QoS can
> (really?) be
> > granted to packet flows, and routing is more
> faster.
> 
> Forget about the "faster". Today the forwarding
> happens either in 
> hardware and is wire-speed for IPv4/IPv6 as well. Or
> it's the same 
> underlying mechanism in software, e.g. the "CEF"
> table in Cisco 
> routers.
> 

And how many such end addresses are there? Do we need
to throw out the existing gear to move to IPv6?

> QoS for MPLS is in first place the same as for
> IPv4/IPv6. You have 3 
> bits, like the (old) IPv4 Precedence. In theory more
> QoS information 
> could be coded in the label, of course.
> 
> > IPv6 has the "Flow label" field wich makes routing
> faster
> 
> again, the "faster" doesn't matter with today's
> ASICs in place.
> 

But then tomorrow's ASICs will be faster than today's
so why not wait for tomorrow :)) till they are built
??


> > and has less header overhead than ipv4 (or
> mpls+ipv4)
> 
> n*4+20 vs. 40 - less overhead?
> 
> > And i think flow label could have the same use as
> > the mpls label value...
> >
> > How is MPLS to IPv6 related?
> 
> as already answered: the same as MPLS to IPv4.
> Well, there is always a difference between theory
> and implementation. 
> MPLS needs LDP (and RSVP depending on what you do),
> LDP uses IP UDP and 
> TCP. Although informations within are "TLV" coded
> and thus expandable I 
> haven't seen any IPv6-based LDP on my Cisco so far.
> Read: you may have 
> IPv4 to run protocols like LDP to finally run MPLS
> carrying IPv6 
> packets.
> 
> > Are they technologies that have nothing to do with
> each other?
> 
>  From a generic point of view: correct.
> 
> > Or MPLS can bring new functionalities to IPv6
> networks (like to IPv4), 
> > and
> > so mpls+ipv6 would have a sense?
> 
> exactly. Hope I don't start a religious war now but
> look upon IPv6 as 
> an IPv4 with larger addresses, a more structured
> approach to "ip 
> options", avoiding fragmentation (on transit
> routers) and such. In 
> short: more addresses ;-)
> 

> Same as for IPv4: TE capabilities, allows you to
> integrate ATM into 
> your IP packet network, [...].
> 
But why woould I need ATM then?


		
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