From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Thu Aug 23 2007 - 19:59:31 ART
The P and PE terminology just relates to who is imposing/deposing
the label stack, not directly to L2/L3 VPNs. PE routers are always the
devices that take an IP packet and add an MPLS label (imposition), or take a
packet that already has a label and remove it to expose an IP packet
(disposition). In some other special cases you can have P routers that
impose/depose (as in P to P TE tunnels), or PE routers that impose/depose on
packets that are already labeled (CSC), or PE routers that impose/depose on
packets that aren't IP at all (VPLS, AToM).
Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
________________________________________
From: Gabriel Nunes [mailto:gabriel.nunes@gmail.com]
Sent: Thursday, August 23, 2007 3:52 PM
To: Mohamed M Moustafa
Cc: C SAMARTH; Gregory Gombas; Cisco certification; Brian McGahan
Subject: Re: Question for you ISP guys
Hi Mohamed,
P and PE belongs to VPN MPLS terminology. If you have an ISP backbone where
you don't have MP-BGP running, you don't have P and PE routers. In this case
you would have an MPLS core backbone only with probaly a Traffic
Engineering...
Gabriel Nunes
CCIE#17737
On 8/23/07, Mohamed M Moustafa <mmma@gawab.com> wrote:
Hi,
As Brian has stated, only the core routers (P routers) are not running BGP
as they only do label switching but the edge routers (PE routers) still
need to run BGP, this is always the case of an MPLS backbone providers, but
all the routers needs to run IGP (most commonly ISIS or OSPF), before even
MPLS can operate, and the first benefit of MPLS is that the core routers
needs not a full internet routing table as they just do label switching,
and then comes all the advanced features of MPLS.
HTH,
Mohammed Mahmoud.
C SAMARTH < samarth_04@hotmail.com> wrote on 23 Aug 2007, 08:08 PM:
Subject: RE: Question for you ISP guys
>Has any of the ISP's completely stopped running any BGP in their core and
>running only MPLS + IGP there?
>
>Best Wishes,
>SAMARTH
>CCIE #18535
>
>> From: bmcgahan@internetworkexpert.com> To: ggombas@gmail.com ;
>ccielab@groupstudy.com> Subject: RE: Question for you ISP guys> Date: Thu,
>23
>Aug 2007 11:34:39 -0500> > A lot of large providers run IS-IS as their IGP,
>BGP at the edge,> and then MPLS in the core. Running MPLS not only enables
>advanced services> like traffic engineering and L2/L3 VPNs, it also removes
>the requirement of> transit devices having to carry the full public BGP
>table.
>It works this> way because the MPLS enabled routers don't need to know what
>the final> destination of a packet is, only what the exit point is.> >
>HTH,> >
>Brian McGahan, CCIE #8593 (R&S/SP/Security)>
>bmcgahan@internetworkexpert.com >
>> Internetwork Expert, Inc.> http://www.InternetworkExpert.com > Toll Free:
>877-224-8987 x 705> Outside US: 775-826-4344 x 705> 24/7 Support:
>http://forum.internetworkexpert.com> Live Chat:
> http://www.internetworkexpert.com/chat/> > > > -----Original Message----->
>>
>From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On Behalf Of> >
>Gregory Gombas> > Sent: Thursday, August 23, 2007 10:37 AM> > To: Cisco
>certification> > Subject: Question for you ISP guys> > > > For those of you
>with ISP experience, can you tell me what routing> > protocols do service
>providers typicall run within their AS?> > > > Do you have every single
>router
>running BGP? I can't imagine> > redistributing 225k+> > routes into an IGP,
>so
>how do you pass these routes withing your AS?> > > > If you are using iBGP
>what are you using to transmit next hop> > information (as iBGP does not
>normally update the next hop of the> > external AS)?> > > > Can someone
>point
>me to some documentation showing typical ISP routing> > design?> > > >
>Thanks,> > Greg> > > >
>_______________________________________________________________________> >
>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
>
---------------------------------------------
Free POP3 Email from www.Gawab.com
Sign up NOW and get your account @gawab.com!!
This archive was generated by hypermail 2.1.4 : Sat Sep 01 2007 - 11:32:12 ART