Re: OT: GS Archives Search

Even though redistribution has something to do with getting into MP-BGP,
Redistribution has nothing to do Technically with a route coming INTO the
VPN. The redistribution mechanism on egress happens when the BGP route has
already been accepted into the VRF and is STILL a BGP prefix. If
redistribution is NOT performed, the prefix WILL be visible by the PE in the
VRF but the Customer will NOT see this.

I posted this to complete the thought due to confusion about redistribution
as well.

Paul

-- 
Paul Negron
CCIE# 14856 CCSI# 22752
Senior Technical Instructor
> From: Brian McGahan <bmcgahan_at_ine.com>
> Reply-To: Brian McGahan <bmcgahan_at_ine.com>
> Date: Tue, 27 Mar 2012 10:52:36 -0500
> To: Narbik Kocharians <narbikk_at_gmail.com>
> Cc: Marko Milivojevic <markom_at_ipexpert.com>, Yemi Salau
> <salauolayemi_at_yahoo.co.uk>, "ccielab_at_groupstudy.com" <ccielab_at_groupstudy.com>
> Conversation: OT: GS Archives Search
> Subject: RE: OT: GS Archives Search
> 
> Don't worry m8, you learn something new every day.
> 
> 
> From: Narbik Kocharians [mailto:narbikk_at_gmail.com]
> Sent: Tuesday, March 27, 2012 10:43 AM
> To: Brian McGahan
> Cc: Marko Milivojevic; Yemi Salau; ccielab_at_groupstudy.com
> Subject: Re: OT: GS Archives Search
> 
> hahahahahaha
> 
> I thought it all happens automagically.
> 
> 
> 
> On Tue, Mar 27, 2012 at 8:34 AM, Brian McGahan
> <bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com>> wrote:
>> The "Route-target" is a BGP extended community that indicates which routes
> should be exported from a given VRF or imported into a given VRF.
> The Route Target doesn't control which routes leave the VRF to go into VPNv4
> BGP, redistribution controls this.  If you don't set a Route Target the VPNv4
> routes will still originated, but no one will be able to import them on the
> other side.  This is actually a common misconfiguration for MPLS L3VPN.
> 
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>
> 
> Internetwork Expert, Inc.
> http://www.INE.com
> 
> From: Narbik Kocharians [mailto:narbikk_at_gmail.com<mailto:narbikk_at_gmail.com>]
> Sent: Monday, March 26, 2012 9:18 PM
> To: Brian McGahan
> Cc: Marko Milivojevic; Yemi Salau;
> ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
> Subject: Re: OT: GS Archives Search
> Since we all know what VRFs are. Remember that the VRF is NOT operational
> without an RD.
> What is an RD? An RD is a 64 bit value that is attached to the customer's IPv4
> address, to make it a Unique 96 bit address called VPNv4. These addresses are
> ONLY exchanged between the PE routers. In Brian's example, RDs distinguish one
> route from another, in his example 10.0.0.0:A from 10.0.0.0:B.
> 
> I think that the name "VPNv4" is the worst name they could assign to these
> addresses, because many people think that RDs define the VPN, and they DO NOT
> define the VPN.
> 
> Once the PE router attaches the RD to the CE routes, it then sends the VPNv4
> address/es to the other PE router/s. The receiving PE router strips the RD
> from the VPNv4 prefix, and it's left with an IPv4 address.
> 
> NOW..How does the receiving PE know which VRF does the IP address belong to?
> The answer is "Route-Target".
> 
> The "Route-target" is a BGP extended community that indicates which routes
> should be exported from a given VRF or imported into a given VRF.
> I hope this helped.
> On Mon, Mar 26, 2012 at 6:27 PM, Brian McGahan
> <bmcgahan_at_ine.com<mailto:bmcgahan_at_ine.com>> wrote:
> Personally that seems overly confusing to me.  Yes Route Targets are an
> attribute of the route, but that attribute is not part of the BGP Bestpath
> Selection.  I'm not sure how it ties together.  It's simpler to think of it
> this way:
> 
> It's given that customers of a Service Provider will have overlapping IP
> addressing in their VPNs, e.g. you will have more than two customers who use
> the 10.0.0.0/8<http://10.0.0.0/8> network.  The RD is how you tell them apart.
> If you have customer "A" with RD "A" and customer "B" with RD "B" the routes
> "A:10.0.0.0/8<http://10.0.0.0/8>" and "B:10.0.0.0/8<http://10.0.0.0/8>" become
> unique.  This is all the RD does.
> 
> The Route Target tells you which VRF table the route belongs to.  You have to
> separate the two attributes because sometimes you want the same route to
> belong to multiple VRF tables.   This is common in what's known as "Central
> Services VPNs".  For example if the Service Provider hosts email for
> customers, that route to the mail server would have to be in the routing table
> of multiple customers.  This doesn't break the rule of the route having to be
> unique though, which is what the RD does.
> 
> Like I said you may be able to find more clarification in this video:
> http://goo.gl/Y0imB.
> 
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com<mailto:bmcgahan_at_INE.com>
> 
> Internetwork Expert, Inc.
> http://www.INE.com
> 
> -----Original Message-----
> From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>
> [mailto:nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>] On Behalf Of
> Marko Milivojevic
> Sent: Monday, March 26, 2012 6:00 PM
> To: Yemi Salau
> Cc: ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
> Subject: Re: OT: GS Archives Search
> 
> Simple reason - prefixes are passed on through the bestpath selection process
> where the best one is chosen based on attributes. RT is a community, which is
> an attribute. This means that given two prefixes with different RTs would be
> treated as equals when it comes to bestpath selection. With RD we extend the
> prefix space to 86 bits and then use those for comparison instead of 32bit
> ones.
> 
> [ iPhone, brevity, etc disclaimer :-) ]
> 
> --
> Marko Milivojevic - CCIE #18427
> 
> :: This message was sent from a mobile device. I apologize for errors and
> brevity. ::
> 
> On Mar 26, 2012, at 14:44, Yemi Salau
> <salauolayemi_at_yahoo.co.uk<mailto:salauolayemi_at_yahoo.co.uk>> wrote:
> 
>> Thanks Marko, reading RFC 4364, I was trying to figure out why RT
>> couldn't
> do the same job of RD for uniquely separating VPN-IPv4 routes within the
> provider MPLS cloud. I'll watch your video when I get home. Many Thanks.
>> 
>> From: Marko Milivojevic <markom_at_ipexpert.com<mailto:markom_at_ipexpert.com>>
>> To: Yemi Salau <salauolayemi_at_yahoo.co.uk<mailto:salauolayemi_at_yahoo.co.uk>>
>> Cc: ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
>> Sent: Monday, 26 March 2012, 16:25
>> Subject: Re: OT: GS Archives Search
>> 
>> 
>> Yemi,
>> 
>> I'm not sure about the Archive search, but I can certainly help you
>> with RD
> and RT. Almost two years ago I hosted a free online training session called
> "MPLS 101". You can find it, together with all other recorded vLectures on
> many other subjects here:
>> 
>> http://bit.ly/vLecture
>> 
>> Please go ahead and watch it and if you have any questions feel free
>> to ask
> them here.
>> 
>> --
>> Marko Milivojevic - CCIE #18427 (SP R&S) Senior CCIE Instructor -
>> IPexpert
>> 
>> On Mon, Mar 26, 2012 at 10:18, Yemi Salau
> <salauolayemi_at_yahoo.co.uk<mailto:salauolayemi_at_yahoo.co.uk>> wrote:
>> Guys,
>> 
>> I remember a time where I was able to search the GS archives for
>> stuffs. Is
> this still available today? I want to search out some stuffs on RD vs RT.
>> 
>> Yemi
>> 
>> 
>> Blogs and organic groups at http://www.ccie.net
>> 
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> 
> 
> 
> 
> 
> 
> 
> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com<http://www.MicronicsTraining.com>
> Sr. Technical Instructor
> YES! We take Cisco Learning Credits!
> A Cisco Learning Partner
> 
> 
> 
> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com<http://www.micronicstraining.com/>
> Sr. Technical Instructor
> YES! We take Cisco Learning Credits!
> A Cisco Learning Partner
> 
> 
> Blogs and organic groups at http://www.ccie.net
> 
> _______________________________________________________________________
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Blogs and organic groups at http://www.ccie.net