[AusNOG] VPLS OSPF question

[Brad Gould]

Why are you going down the VPLS path/topology?

VPLS is primarily for Layer 2 connectivity between sites - transporting 
vlans to various sites, it doesnt sound like thats what you require.

It sounds like what you actually want is an Layer 3 MPLS VPN.  At each 
site you run an IGP or iBGP to the service provider, who emulates your 
core network aka "the MPLS VPN", and your done.


Brad


On 16/04/2013 4:44 PM, Brad McGinn wrote:
> Hi AusNog list,
> Long time listener, first or second time caller.
> I know this list is pretty specific to Service Providers so I'm hoping
> any of you who not only know carrier networks, but also have an insight
> into enterprise networks maybe able to help me to get a view (or even
> help understanding) of the pros and cons of running OSPF or BGP across a
> VPLS network.
> I respectfully ask your advice.
> I am an enterprise network engineer, not a service provider however I
> hope you don't hold that against me.  We run OSPF in our Data Centre and
> BGP into a MPLS network that all of our sites connect into.
> My fairly basic understanding of VPLS is kind of like EoMPLS or even one
> big broadcast domain.  I assume any IGP could potentially work across it
> but some factors must be taken into consideration:  eg flapping sites,
> latency, reference bandwidth, DR/BDR placement, multicast transmission
> and so on.
> So, with that in mind, I'm wondering the following:
> -    would it be wise to run an IGP across a VPLS backbone with over 200
> sites? or would BGP be better? or even something else?
> -    if an IGP is the go, would one use OSPF?
> -    if OSPF, do you think it would be wiser to run a separate OSPF
> process for the VPLS connected sites and a separate OSPF process for the
> DC?  and then redistribute or just summarise right there? (so as to
> protect the DC from OSPF recalculations when sites go up and down)
> -    if BGP would be the go I'm wondering how one might go about it..  I
> know that all iBGP neighbours must have a route to the peering IP of all
> other iBGP routers so I would assume an IGP must be run anyway???
> -    cisco say that anything more than 50 routers on an area is a bad
> idea, so if I have over 200 sites potentially on the VPLS, will OSPF cut it?
> I guess i'm just trying to get my head around the different technology.
> I'd love to keep the stability that BGP brings, but also would like to
> be able to make use of the bandwidth that VPLS gives.
> Any hints or tips will be gratefully received and thank you for
> any help.  If you would like to keep from cluttering up
> subscriber's inboxes, please reply offlist.
> Again, thanks for any help.
> Regards,
> Brad David
>
>
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-- 
Brad Gould, Network Engineer
Internode
PO Box 284, Rundle Mall 5000
Level 5, 150 Grenfell Street, Adelaide 5000
P: 08 8228 2999  F: 08 8235 6999
bradley at internode.com.au; http://www.internode.on.net/