The MPLS WG Archive

[Robert Raszuk <raszuk@cisco.com>]

Sam,

Manual ibgp peering is fine when you have no more then 5 PEs. For more
then that just use bgp route reflectors and the problem is solved. One
session per PE (maybe two for redundancy).

Rgs,
R.

> Sam Ford wrote:
> 
> Hello,
> 
> Thanks for clarification.
> 
> Another slightly different question. The way I
> understood based on some vendor's
> manuals, IBGP peering between PEs are manually
> provisioned, using bgp neighbor command, for VPN
> routes
> distribution among PEs. It may require lot of
> effort to do it when setting up a pretty big VPN
> with many sites without route reflector.
> 
> Are there implementations using automatic discovery
> of PEs for VPNs? if so, what kinds of method do
> they use for discovery (not for data transfer),
> e.g. emulated LAN, IGP extension, etc?
> 
> Regards,
> -SF
> 
> --- Ajay Simha <asimha@cisco.com> wrote:
> > On Wed, 26 Sep 2001, Sam Ford wrote:
> >
> > > Hello,
> > >
> > > I have the following questions on MPLS based VPN:
> > > - One of the advantage over traditional VPN
> > >   is cited as elimination of full mesh overlay
> > >   when connecting multiple sites.
> > >   Then, when does LSP setup in MPLS domain
> > >   supporting a particular VPN?
> > >   If it needs to be set up statically when
> > configuring
> > >   VPN, it doesn't seem to be different from
> > > traditional
> > >   mesh overlay.
> > >   Is it set up when traffic is generated?
> >
> > You have to remember MPLS is a control driven
> > mechanism.  Nothing gets setup
> > *when* there is traffic.  It is setup ahead of time.
> >
> > Does the LSP need to be setup statically when
> > configuring VPNs?
> >
> > Depends on the implementation.  I have seen several
> > implementations where LSPs
> > are setup automatically for all the IGP derived
> > routes - this would include
> > the PEs and thus nothing special has to be done when
> > you configure a VPN.
> >
> >  > -
> > >Does MPLS based
> > >VPN require the same level
> > >   of encryption as with traditional IP VPN?
> > >   If not, how is it protected from unathorized
> > >   access to data or tapping?
> >
> > Now you are asking religious question :-)
> > Of course the answer is always depends :-)
> >
> > When you say IP VPNs do you mean IPSEC based VPNs?
> > If yes, IPSEC based VPNs
> > have a different purpose in life.  Right now as I
> > type this email, I'm using
> > an IPSEC based VPN model and that is because I'm
> > going over the public
> > Internet.
> >
> > If I got a dedicated ISDN/DSL or any other type of
> > access into my company's
> > network without going over the public Internet I may
> > not need encryption.
> >
> > If I still feel I need encryption, just as folks did
> > in frame relay and atm
> > networks they can encrypt their data.
> >
> > -ajay
> >  > > Thanks in advance,
> > > -SF
> 
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