Re: Just shy of OT MPLS Question

Sorry just making sure. So I suppose TE is out for our little scenario
here. L3/L2vpn? Are there any real world uses for this or does it go in
the stupid router tricks file?

From:
Rick Mur <rmur_at_ipexpert.com>
To:
<Keegan.Holley_at_sungard.com>
Cc:
ALL From_NJ <all.from.nj_at_gmail.com>, Cisco certification
<ccielab_at_groupstudy.com>, nobody_at_groupstudy.com, Scott Morris
<smorris_at_ine.com>, JR Garcia <ttuner_at_gmail.com>
Date:
12/23/2009 06:52 AM
Subject:
Re: Just shy of OT MPLS Question

I think I answered the question in my previous mail :-)

You CAN use BGP to get rid of an IGP, but you CAN'T use LDP then, LDP uses
an IGP protocol to allocate labels. If you want to allocate labels for BGP
prefixes, you should use BGP as label distribution as well (neighbor
send-label command).

On the other hand, I would never implement this. An IGP with LDP is far
more easier to setup and maintain than using BGP for this purpose.

-- 
Regards,
Rick Mur
CCIE2 #21946 (R&S / Service Provider)
Sr. Support Engineer b IPexpert, Inc.
URL: http://www.IPexpert.com 
On 23 dec 2009, at 12:43, <Keegan.Holley_at_sungard.com> wrote:
That's interesting.  I think that was my original question whether you 
could build your base routing table using bgp and have LDP/RSVP base it's 
label assignments on it.  I knew you could do it with statics (routes not 
labels sorry..)  So just so I'm sure I understand you're saying that 
there's no way to replace your IGP with bgp even if the next-hop and other 
issues are taken care of?  I was just curious since I've seen some of the 
smaller carriers where every router is a PE router so you cannot get away 
from doing BGP in the core.  I was just curious if there was a way to keep 
from doing the IGP in the core and maybe save some resources that way even 
at the expense of TE. 
From: 
Rick Mur <rmur_at_ipexpert.com> 
To: 
<Keegan.Holley_at_sungard.com> <Keegan.Holley_at_sungard.com> 
Cc: 
ALL From_NJ <all.from.nj_at_gmail.com>, Cisco certification <
ccielab_at_groupstudy.com>, nobody_at_groupstudy.com, Scott Morris <
smorris_at_ine.com>, JR Garcia <ttuner_at_gmail.com> 
Date: 
12/23/2009 03:00 AM 
Subject: 
Re: Just shy of OT MPLS Question
The IGP label is usually the 'outer' label (unless another label get's 
attached in a CsC environment). Inner label is the VPN label, Outer label 
is the IGP label. 
A flat MPLS network with statics? I would never ever build a network with 
static label assignments :-) (doesn't even work on Cisco, it does on 
Juniper) 
You can't use BGP and LDP to assign labels. If you want BGP prefixes to 
get a label allocated, you do this within BGP and then BGP advertises and 
assigns labels for those prefixes. This will definitely work. So NO LDP 
then :-) 
-- 
Regards,
Rick Mur
CCIE2 #21946 (R&S / Service Provider)
Sr. Support Engineer b IPexpert, Inc.
URL: http://www.IPexpert.com 
On 23 dec 2009, at 03:52, <Keegan.Holley_at_sungard.com> <
Keegan.Holley_at_sungard.com> wrote: 
<nobody_at_groupstudy.com> wrote on 12/22/2009 02:36:40 AM:
> I'm also a bit confused with the term MPLS Tunnels. Do you mean a 
> normal MPLS VPN or a TE Tunnel, since both require totally different 
things.
> 
Neither, I'm not that familiar with the term.  I always took tunnel to 
mean anything encapsulated in something else and thus interchangeable with 
LSP.  In other words I meant LSP's. 
> For IBGP it's not really recommended and same as Bryan said, I never
> tested this. It does is an implementation for Inter-AS 
> configurations to use the BGP send-label command to advertise 
> prefixes and labels in BGP, which works :-)
> 
Are these inner or outer labels? Inner with one outer to keep you from 
having to run LDP with a foreign router? I would assume they are the inner 
labels and then your RSVP/LDP protocol would take care of the outer labels 
used to reach the next AS's router. 
> For TE tunnels, you cannot allocate labels through BGP, but solely 
> through RSVP and a link-state protocol. This is because of he 
> dynamic behavior and the SPF protocol that TE uses to calculate 
> paths throughout the network. A distance vector protocol like BGP 
> would not work as within a link-state you have the full topology of 
> the network available to calculate your path on (within an area of 
course).
Throw TE (and usefullness with it...) out the window for a minute.  For 
example you can create a flat MPLS network using static routes. 
> 
> So for MPLS VPN's this should work, advertise the PE loopbacks in 
> IPv4 BGP and advertise VPN labels in VPNv4 BGP. You should run BGP 
> on the P of course then. Cool thing to lab it up :-)
Could you use BGP as the only protocol and just enable LDP on each 
interface to do the switching?  Assuming next hop reachability was taken 
care of (without static routes).  Don't have any SP stuff setup right now 
or I'd try it out myself. 
> 
> 
> -- 
> Regards,
> 
> Rick Mur
> CCIE2 #21946 (R&S / Service Provider)
> Sr. Support Engineer  IPexpert, Inc.
> URL: http://www.IPexpert.com
> 
> On 22 dec 2009, at 06:29, Scott Morris wrote:
> 
> > Yup, you can.
> > 
> > 
> > 
> > 
> > *Scott Morris*, CCIE/x4/ (R&S/ISP-Dial/Security/Service Provider) 
#4713,
> > 
> > JNCIE-M #153, JNCIS-ER, CISSP, et al.
> > 
> > JNCI-M, JNCI-ER
> > 
> > evil_at_ine.com
> > 
> > 
> > Internetwork Expert, Inc.
> > 
> > http://www.InternetworkExpert.com
> > 
> > Toll Free: 877-224-8987
> > 
> > Outside US: 775-826-4344
> > 
> > 
> > Knowledge is power.
> > 
> > Power corrupts.
> > 
> > Study hard and be Eeeeviiiil......
> > 
> > 
> > 
> > JR Garcia wrote:
> >> pretty sure you can exchange labels via ibgp using the "send-label"
> >> command. Eg: neighbor 1.1.1.1 send-label 
> > 
> > 
> > Blogs and organic groups at http://www.ccie.net
> > 
> >