From: Tarun Pahuja (pahujat@gmail.com)
Date: Wed Oct 24 2007 - 12:33:15 ART
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.
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Fri Nov 16 2007 - 13:11:18 ART