From: sheherezada@gmail.com
Date: Wed Oct 24 2007 - 13:27:19 ART
I agree with you that BGP is preferred because of better control of
customer route control. In fact, all customer routers are carried in
BGP. However, I think that the context was MPLS VPN. I don't see the
purpose of customer route filtering in this case - the network should
be transparent to the customer.
Mihai Dumitru
CCIE #16616 (SP, R&S)
On 10/24/07, Tarun Pahuja <pahujat@gmail.com> wrote:
> The Following documents talks about the pros and cons of using OSPF and BGP
> as a Routing protocol between CE and PE in a MPLS network.
>
> http://tools.ietf.org/html/draft-rosen-vpns-ospf-bgp-mpls-06
>
> Many providers prefer BGP as it gives them better control over Customer
> route filtering, and access to other attributes BGP has to offer.
>
> HTH,
> Tarun Pahuja
> CCIE #7707(R&S,Security,SP,Voice,Storage),CCSI
>
>
> On 10/24/07, Daniel Kutchin <daniel@kutchin.com> wrote:
> >
> > The 32 OSPF processes limit has been lifted in the following IOS versions
> >
> > 12.3(4)T
> > 12.0(27)S
> > 12.2(25)S
> > 12.2(18)SXE
> >
> > See this link:
> >
> > http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cg/hirp_c
> > /ch15/hospfvf.pdf
> >
> >
> >
> >
> > Daniel
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > sheherezada@gmail.com
> > Sent: Dienstag, 23. Oktober 2007 23:26
> > To: CCIE Abreu
> > Cc: ccielab@groupstudy.com
> > Subject: Re: BGP vs OSPF
> >
> > In my opinion, BGP has the lowest overhead, because you don't run yet
> > another routing process on the PE (and you don't have to
> > redistribute).
> >
> > OSPF has or had some limitations as per number of routing processes on
> > the PE (limited at 32), with obvious implications on scalability. I
> > am sure that you will find a document explaining this somewhere.
> >
> > With the OSPF redistribution in the MP-BGP and viceversa, you cannot
> > get intra-area routes across the MPLS cloud. So if you have a direct
> > backup link between say two VPN sites, traffic will always flow
> > through the backup link, because intra area routes are preferred. The
> > sham link helps you overcome this issue when you want traffic flowing
> > across the MPLS cloud instead.
> >
> > HTH,
> >
> > Mihai
> >
> > On 10/23/07, CCIE Abreu <ccie.abreu@gmail.com> wrote:
> > > Hello guys,
> > >
> > > This may sound like a question for the CCIE SP group, but I think it
> > applies
> > > here as well, since it's about BGP and OSPF.
> > >
> > > Can anyone explain the main reason why BGP is widely used as the
> > protocol
> > to
> > > connect remote sites that are part of a MPLS network?
> > > Since we may be running OSPF in each remote site, why can't we have all
> > OSPF
> > > all the way, let's say, having all edge routers as part of area 0?
> > >
> > > And what's the deal with OSPF sham links? I don't get those either.
> > >
> > > Thanks.
> > >
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