Re: Regarding bridge group and Bridge domain

Aaron,

I used the Internetworking Concept when I worked with an ATM backbone years
ago. If you had an ATM backbone with Frame Relay on the edges, you would
need to take the data that was using Frame-Relay for Transport and have it
ride the backbone in ATM. Eventually it would have to be dropped off as
Frame-Relay again. This was Network Interworking (FRF8). When a client had a
Frame Relay Access Device on the edge (FRAD) and an ATM edge point. I would
not need to convert back to Frame-Relay but would need to leave it within
ATM. This was called Service Interworking.(FRF5)

This concept is also supported with MPLS. If we have Frame on one side and
Ethernet on the other, as an example, the thing they have in common is they
both carry IP traffic. All we do is terminate the framing on one end .
Remove the IP packet from the frame (Frame Relay) and have it ride over an
IP backbone. Reinsert the IP info into a different encapsulation (Ethernet)
and send it to the end device. We use NLPID to accomplish this, which is why
we need IETF Frame Relay on one side.

I have over simplified this example to help you understand the concept since
that's what you were asking....right?

Paul

-- 
Paul Negron
CCIE# 14856 CCSI# 22752
Senior Technical Instructor
> From: Aaron <aaron1_at_gvtc.com>
> Reply-To: Aaron <aaron1_at_gvtc.com>
> Date: Fri, 13 Jan 2012 10:00:14 -0600
> To: 'CCIE KID' <eliteccie_at_gmail.com>
> Cc: <ccielab_at_groupstudy.com>
> Subject: RE: Regarding bridge group and Bridge domain
> 
> I don't understand the idea of interworking and what it means yet..however,
> look what I found.  This guy has a small lab showing frame relay to vlan
> (eth) AToM and I see the command "interworking ip" in there too.under the pw
> class.
> 
> http://enotepad.wordpress.com/2010/04/14/framepvctovlan/
> 
> Aaron
> 
>  
> 
> From: CCIE KID [mailto:eliteccie_at_gmail.com]
> Sent: Friday, January 13, 2012 1:16 AM
> To: Aaron
> Cc: Cisco certification
> Subject: Re: Regarding bridge group and Bridge domain
> 
>  
> 
> hi aaron, thanks for the reply
> 
> Can u just give some brief about Atom Interworking. I m not very sure how it
> works. can u give ur thoughts
> one side of Ce to PE is ethernet and the other side is Frame Relay
> 
> On Wed, Jan 11, 2012 at 9:20 PM, Aaron <aaron1_at_gvtc.com> wrote:
> 
> I was told by someone a few months ago when I was config'ing my ASR9K's that
> BG is a way of simply organizing the underlying BD's.  I believe you can't
> configure a BD without first config'ing an owning BG.  So you can have
> several BD's in one overarching BG.  Again, the BD's are organized into a
> BG.  I guess you could create one to one....one bg for one bd....but I
> didn't do my network that way....
> 
> I took common bd's and put them into one bg
> 
> The bd is what gets you the segregated broadcast domain/vlan entity that we
> all understand.  Not the bg.  So the bd = broadcast domain. (funny that bd
> doesn't stand for broadcast domain but instead stands for bridge domain, but
> as I understand, the bd is in fact the broadcast domain....so the bg is a
> way of organizing a bunch of bd's into one overarching bg.)
> 
> Yeah, so I don't think the owning BG allows any technical forwarding of
> traffic or anything like that amongst underlying bd's.
> 
> As I understand it, you MUST enter the "l2vpn" config mode BEFORE you can
> configure any bg/bd at all.
> 
> Also, as I understand it, AToM I think is cisco-speak for EoMPLS.....
> 
> And as I understand AToM/EoMPLS, this is known as MPLS L2VPN.... ethernet
> frames over mpls frames over ethernet frames...don't you love it!
> 
> So stack looks like ... ip/eth/mpls/eth
> 
> Also, as I understand it, there are a variety of ways to accomplish MPLS
> L2VPN/AToM.....i think EoMPLS is one of them....i think there is port mode
> and vlan mode....i think there is VPLS (I believe for multipoint scenarios)
> and I think EoMPLS might be more suited for p-to-p...not sure though, but
> that's what I used in my network for something I'm doing....also, more
> terminology...
> 
> I think in EoMPLS...
> 
> - the connection from edge/customer gear to the mpls imposition/disposition
> device (label cloud edge device) is known as AC (attachment circuit)
> --- so you should probably have (2) AC's, one on each edge of mpls cloud
> that you are emulating layer 2 for...
> - the mpls connection through the mpls cloud I believe is known as PW
> (pseudowire)
> - I think in some gear (ME3600) you provision the pw with command called
> "xconnect" under perhaps the vlan svi or eth port (maybe that's where the
> difference in port mode and vlan mode is for config'ing it)
> - in IOS XR gear I see that it's not xconnect for the pw but is "neighbor
> x.x.x.x" under the owning bd which is of course under the owning bg....
> --- I think in both cases you specify encap mpls for xconnect/neighbor or a
> pw class in which you specifiy in the pw class the encap mpls
> 
> Also in your link to ciscosupport I see that there is another type of maybe
> it's mpls l2vpn, e-line (vpws).
> 
> From your other email, I don't know the difference from local connect and
> local bridging...that link you sent shows local bridging using some dot1q
> stuff on it and even qnq...maybe that's the difference.  Not sure
> 
> This mpls l2vpn stuff btw is *very* different than MPLS L3VPN's....wayyyy
> different.  L3vpn is based on routing tricks with vrf instances and using
> mp-ibgp as the signaling protocol in the mpls cloud to carry the uppermost
> label for l3vpn segregation....(I think I heard someone say recently that
> you don't really have to have an mpls core to do mpls l3vpn's, I was amazed)
> 
> Aaron
> 
> 
> 
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of CCIE
> KID
> Sent: Tuesday, January 10, 2012 12:49 AM
> To: Cisco certification; CCIE OSL
> Subject: Regarding bridge group and Bridge domain
> 
> Hi fellas,
> 
> What is the exact difference between the bridge group and bridge domain  in
> L2VPN configs.
> 
> What is the exact purpose of bridge group and bridge domain in Atom configs
> 
> --
> With Warmest Regards,
> 
> CCIE KID
> CCIE#29992 (Security)
> 
> 
> 
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> -- 
> With Warmest Regards,
> 
> CCIE KID
> CCIE#29992 (Security)
> 
> 
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