Re: OT: GS Archives Search

Here is a fundamental understanding on RD and RT

MPLS VPN routing information flow

* The PE receives IPv4 routing update from the CE router and then installs
them in the configured VRF table

* The PE router "Exports" VPN routes from the VRF table into MPBGP session
and propagates them to the other end of the PE route as a 96-bit VPNv4
prefix -- the VPNv4 addresses are 64-bit Route Distinguisher (RD) that is
prepended to an IPv4 address to make them globally unique.

* The receiving PE router "Imports" the incoming VPNv4 routers and places
them in the appropriate VRF table. This is based on the route target (RT)
that comes with the MP BGP update. Route targets are attributes used to
support complex MPLS VPN Architecture in order to indicate VPN membership
in situations where a single site participate in more than one VPN

*The routes installed in the VRF table on the PE router is sent to the CE
router as an IPv4 prefix

You can read more @

source: http://uyota.blogspot.ca/2011/12/mpls-vpn-fundamentals.html

cheers

On Tue, Mar 27, 2012 at 1:04 PM, John Neiberger <jneiberger_at_gmail.com>wrote:

> I know virtually nothing about RDs and RTs, but when I'm teaching
> stuff that I am familiar with, I like to start out with the problem.
> My mentor Howard Berkowitz is always fond of asking, "What problem are
> you trying to solve?" Everything in networking is a solution to some
> problem; understand the problem and you understand the solution.
>
> If I'm understanding this correctly, RDs might be all that's necessary
> for a basic VPN where customer A never needs to reach Customer B and
> vice versa. RDs solve the problem of needing to create unique routes
> in BGP for VPNs. But if your requirements change, you might run into
> new problems. What if your basic VPNs are working but you suddenly
> develop the need for some customers to see certain routes from other
> customers? As I understand it, that's where Route Targets come in.
> They solve a new and slightly different problem, right?
>
> John
>
> On Tue, Mar 27, 2012 at 10:03 AM, Marko Milivojevic <markom_at_ipexpert.com>
> wrote:
> > I simply cannot add anything to the fantastically simple explanation
> Carlos provided. If you haven't, read his response. Then go back and read
> the one I sent last night.
> >
> > Always question WHY and you will learn. I like your learning approach -
> it's the right way to do it.
> >
> > --
> > Marko Milivojevic - CCIE #18427
> >
> > :: This message was sent from a mobile device. I apologize for errors
> and brevity. ::
> >
> > On Mar 27, 2012, at 5:40, Olayemi Salau <salauolayemi_at_googlemail.com>
> wrote:
> >
> >> Marc...thanks, this is the search page I was looking for.
> >>
> >> I wanted to search the archives to see if someone has asked why MP-BGP
> couldn't stick with RTs to "distinguish" customer routes, by extending
> normal 4 octect addresses with RT and not RDs, this will still achieve a 96
> bit addr that can be used for MPBGP. I understand why RD cant do the job of
> RTs(flexibilty, complexities and load sharing traffic MPLS VPN traffic
> etc.), but I don't get why RTs can't do the job of RDs. I think the simple
> answer to this lies in the design/conceptual decisions. Perhaps RD was
> designed before RTs came into being. Nothing in the RFC 4364 to say this as
> I read.
> >>
> >> Like everyone said, we all know what they are n do. There are some
> design decisions fundamentals that cant be questioned I suppose, or maybe
> they can....like why Area 0 (not Area 1) for OSPF BB and Level2 (not
> Level0) "contiguousness" for ISIS, why does higher priorities in OSPF and
> lower BID in SPT win elections .....etc
> >>
> >> I thank everyone for their explanations of RT/RD. Very much appreciated.
> >>
> >> Yemi
> >>
> >> On Mar 27, 2012, at 6:19, marc edwards <renorider_at_gmail.com> wrote:
> >>
> >>> Answer to your original question:
> >>>
> >>> http://groupstudy.com/cgi-bin/search
> >>>
> >>> Now a great new thread in the archives from our experts as well :)
> >>>
> >>> HTH
> >>>
> >>> Marc
> >>>
> >>> On Mon, Mar 26, 2012 at 10:18 AM, Yemi Salau <salauolayemi_at_yahoo.co.uk
> >wrote:
> >>>
> >>>> Guys,
> >>>>
> >>>> I remember a time where I was able to search the GS archives for
> stuffs.
> >>>> Is this still available today? I want to search out some stuffs on RD
> vs RT.
> >>>>
> >>>> Yemi
> >>>>
> >>>>
> >>>> Blogs and organic groups at http://www.ccie.net
> >>>>
> >>>>
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Received on Tue Mar 27 2012 - 13:16:52 ART