Re: MPLS CE, PE definition

From: Scott Morris <swm_at_emanon.com>
Date: Sun, 02 May 2010 08:47:55 -0400

 Managed CE's bring a whole different picture in. It all boils down to
what the SP finds easier (e.g. what translates to less help calls by the
customers and less technician time to work on/fix/tweak/etc). It's a $$
game.

When this all started, by the way, it was (and still may be depending on
the specific equipment/IOS used on the SP edge) a routing-process #
issue. In most devices, there's a maximum of 32 routing processes that
can be used. While we'd love to see the world run OSPF, unfortunately,
each instance is a routing process for the IOS. I believe the new
S-trains (SRD/SRE) and XR versions eliminate this problem and make it
more total-memory rather than process number....

But BGP was the simple common denominator that had to be run anyway, and
offered INTRA-process separation of tables.

So, sorry to rain on things here (as it appears to be a fun contest of
pulling pants down that I'm not particularly interested in) but an SP is
concerned about "reliable" only as much as it translates to lower
operations/support cost. Only the larger customers (commanding that "do
this or I'll pull my $$ to another provider) really get to command the
tweaks and entertaining features. "Normal" MPLS VPN customers have to do
what they are told, or get handed a managed CE router with the phrase
"tough patooties".

The funny thing is that as good network engineers, we can MAKE things
work just about any way till Sunday. But when it comes to making a
replicatable process to roll out en-masse, that logic doesn't hold very
long.

Just my six cents... (I figured I've collected a couple from global SPs
over the years, so I may as well share them here!)

But in design methodology, the funny thing is that there aren't really
"right" answers. There are "what works for me in this particular
situation" answers. So you can both share in being correct (and please
(insert favorite deity here) keep your pants pulled all the way up!).

Scott

Kambiz Agahian wrote:

  Joe,
  
  It's actually less flexible and more resource intensive ;-) but it does
  offer a couple of major advantages.
  
  Different carriers use different CE-PE routing protocols and if you
  interview them you will hear a bunch of different reasons. In the US,
  you see the exact same thing. This is somehow like the famous "OSPF or
  IS-IS" question...both have their own fans.
  
  But what sort of flexibility do you ever need to have between 2 hops?
  
  If you talk to those who are big BGP fans as a CE-PE they'd mostly talk
  about the "built-in redistribution" feature (absolutely true) but at the
  cost of slower convergence. I've heard some other reasons like "we only
  need to hire BGP guys then!" etc.
  
  But what sort of convergence?
  
  As an MPLS SP the only thing that I care about is a reliable, easy to
  set up, configure and tshoot link as my PE-CE but as a customer probably
  you're seeking some more vital features like "what if my primary link
  goes down?", "what if I want to switch over to a SP2 if SP1 is down?",
  "what if the IP SLA for jitter keeps complaining and I prefer to route
  through SP2?" etc. well, BGP does do the job but not necessarily in the
  grace period of time mandated by your critical applications like Call
  managers and public servers.
  
  Does SP1 care?
  Probably they don't, especially in the markets that you see some sort of
  natural monopoly. But I know some service providers working on this now.
  
  In theory, there are heaps of different options to improve this
  experience but at the end of the day you as a customer have to deal with
  their sluggish BGP behavior.
  
  Juniper is actively working on this, and Cisco does have some
  features...but anyway our SP's are far behind; we're talking about a
  massive hardware/software upgrade especially if the feature needs to be
  configured on both ends.
  
  Cheers,
  
  --------------------------
  Kambiz Agahian
  CCIE (R&S), CCSI, WAASSE, RSSSE
  Technical Instructor
  CCBOOTCAMP - Cisco Learning Solutions Partner (CLSP)
  Email: kagahian_at_ccbootcamp.com Toll Free: 877-654-2243
  International: +1-702-968-5100
  Skype: skype:ccbootcamp?call FAX: +1-702-446-8012
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  -----Original Message-----
  From: nobody_at_groupstudy.com [ mailto:nobody_at_groupstudy.com ] On Behalf Of
  Joe Astorino
  Sent: Saturday, May 01, 2010 6:14 PM
  To: Jack Router
  Cc: Kambiz Agahian; ccielab_at_groupstudy.com Subject: Re: MPLS CE, PE definition
  
  PS -- I used to work for a large international company with a global
  MPLS environment. It was much like what you are describing -- managed
  CE routers that ran BGP to the PE routers. We had only read access on
  the managed CE routers. Unfortunately, all of our sites relied
  basically on static routing (sigh) so on the CE router they basically
  just advertised those static routes into BGP. Similarly, in your
  setup the CE router probably learns a bunch of EIGRP routes and they
  likely just advertise them into BGP with the network command....or
  maybe redistribute depending on what exactly they want to accomplish.

  On Sat, May 1, 2010 at 9:10 PM, Joe Astorino <jastorino_at_ipexpert.com> wrote:

    BGP makes it easier and more flexible for your provider. Many
    providers are not going to run an IGP with you at all, and that is
    what you are seeing. Not having at least read only access to their
    managed router is kind of ridiculous though...but that is a business
    decision that likely needs negotiated (AKA Layer 8 problem) : )
    
    On Sat, May 1, 2010 at 8:45 PM, Jack Router <pan.router_at_gmail.com>

  wrote:

      Thanks to all for explanations.
      
      What is the benefit of running separate CE-PE protocol, instead of

  running

      my EIGRP up to the PE ?

      -----Original Message-----
      From: Kambiz Agahian [ mailto:kagahian_at_ccbootcamp.com ]
      Sent: 1-May-10 19:52
      To: Ryan West; Jack Router
      Cc: ccielab_at_groupstudy.com Subject: RE: MPLS CE, PE definition
      
      Ryan,
      
      That box is a pure "managed CE".
      
      When they say BGP they don't mean MP-BGP, more than likely they just
      mean BGP (the CE-PE routing protocol). So probably what you see is
      something like this: EIGRP <-> BGP <-> MP-BGP <-> BGP <-> EIGRP.
      
      You can bother them by asking about the best convergence time they

  can

      offer with their BGP MPLS peer :-D and then ask them to offer BFD on

  top

      of that!

      HTH

      --------------------------
      Kambiz Agahian
      CCIE (R&S), CCSI, WAASSE, RSSSE
      Technical Instructor
      CCBOOTCAMP - Cisco Learning Solutions Partner (CLSP)
      Email: kagahian_at_ccbootcamp.com Toll Free: 877-654-2243
      International: +1-702-968-5100
      Skype: skype:ccbootcamp?call FAX: +1-702-446-8012
      YES! We take Cisco Learning Credits!
      Training And Remote Racks: http://www.ccbootcamp.com

      -----Original Message-----
      From: nobody_at_groupstudy.com [ mailto:nobody_at_groupstudy.com ] On Behalf

  Of

      Ryan West
      Sent: Saturday, May 01, 2010 8:09 AM
      To: Jack Router
      Cc: ccielab_at_groupstudy.com Subject: Re: MPLS CE, PE definition
      
      CE implies no locally running MPLS and not neccessarily customer
      controlled.
      
      Sent from handheld.
      
      On May 1, 2010, at 10:58 AM, "Jack Router" <pan.router_at_gmail.com>

  wrote:

        Hello,
        We have an MPLS service managed by a provider. They have a router on
        our
        location and call it a CE. We do not have access to it. When I asked
        to show
        me the config they refused because this router runs BGP and contains
        confidential information. Provider confirmed that this router
        redistributes
        our EIGRP into their BGP. By my definition this is a PE even if
        located in
        our location, or am I missing something ?
        Thank,

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    --
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    Sr. Technical Instructor - IPexpert
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Received on Sun May 02 2010 - 08:47:55 ART

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