RE: [Softwires] BGP TE attr last call by softwires WG (2nd question)

["Drake, John E" <[e-mail]>]

>2)  Every PE router in the IGP instance has L1VPN routes that 
>it doesn't care about.
>
>3)  The number of L1VPN routes that a given PE router doesn't 
>care about is probably greater than the number of L1VPN routes 
>it does care about.
>
>IB>> As I answered to Yakov if this proves to be a problem you can 
>IB>> configure multiple overlays

JD:  "With sufficient thrust, pigs fly just fine..."  [RFC1295]

>
>Thanks,
>
>John  
>
>>-----Original Message-----
>>From: Igor Bryskin [mailto:[e-mail]]
>>Sent: Wednesday, September 03, 2008 6:47 AM
>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>Cc: Yakov Rekhter; Adrian Farrel; [e-mail]; 
>>[e-mail]
>>Subject: Re: [Softwires] BGP TE attr last call by softwires WG (2nd 
>>question)
>>
>>And I am not arguing that sufficient redundancy must be provided. 
>>However you said:
>>>For your suggested approach to work with sufficient redundancy, the 
>>>topology of the overlay needs to be configured such that
>>every selected
>>>P router is connected to at least two other selected P routers and 
>>>every PE router needs to be connected to at least two selected P 
>>>routers.
>>
>>If you just simply interconnect all VPN-aware PEs into a single ring 
>>via IPinIP tunnels and run an instance of OSPF to distribute 
>>VPN-related information between them, it will provide sufficient 
>>redundancy and involve exactly *zero* Ps.
>>So, I want you to drop your lecturing tone for a minute and 
>simply tell 
>>in what respect in your opinion this approach is not perfect fo the 
>>L1VPN application. Otherwise, I am not interested in this discussion 
>>any longer. I do like to hear comments from other people.
>>
>>Igor
>>
>>
>>
>>----- Original Message ----
>>From: "Drake, John E" <[e-mail]>
>>To: Igor Bryskin <[e-mail]>; Yakov Rekhter 
>><[e-mail]>; Lou Berger <[e-mail]>
>>Cc: Yakov Rekhter <[e-mail]>; Adrian Farrel 
>><[e-mail]>; [e-mail]; [e-mail]
>>Sent: Wednesday, September 3, 2008 8:10:07 AM
>>Subject: RE: [Softwires] BGP TE attr last call by softwires WG (2nd 
>>question)
>>
>>Igor,
>>
>>Actually, I am not sure that you do understand what I wrote, because 
>>you are providing examples of the redundancy that I specified - every 
>>PE router needs to have connectivity to two other routers in the IGP 
>>instance.
>>
>>Thanks,
>>
>>John
>>
>>>-----Original Message-----
>>>From: Igor Bryskin [mailto:[e-mail]]
>>>Sent: Tuesday, September 02, 2008 3:06 PM
>>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>>Cc: Yakov Rekhter; Adrian Farrel; [e-mail]; 
>>>[e-mail]
>>>Subject: Re: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>question)
>>>
>>>Hi John,
>>>
>>>I understand what you are saying and disagree. The overlay I
>>am talking
>>>about logically is a separate network and as any network it 
>should be 
>>>sufficiently redundant to function. There is a number of 
>ways how you 
>>>can address the redundancy concerns. Look at the examples below:
>>>
>>>a) interconnect all VPN-aware PEs into a single ring: 
>>>PE=======PE
>>> ||                  ||
>>>PE              PE 
>>>||                  ||
>>>PE              PE 
>>>||                  ||
>>>...                ....
>>>PE=======PE
>>>
>>>b) connect each PE to two interconnected Ps
>>>
>>>PE              P                PE
>>>                    ||                  
>>>PE              ||                  PE 
>>>                    ||                  
>>>PE              ||                  PE 
>>>                    ||                  
>>>...                ||                  ....
>>>PE              P                PE
>>>
>>>
>>>Note that tunnels can traverse any number of VPN-unaware Ps and PEs.
>>>
>>>Igor
>>>
>>>
>>>----- Original Message ----
>>>From: "Drake, John E" <[e-mail]>
>>>To: Igor Bryskin <[e-mail]>; Yakov Rekhter 
>>><[e-mail]>; Lou Berger <[e-mail]>
>>>Cc: Yakov Rekhter <[e-mail]>; Adrian Farrel 
>>><[e-mail]>; [e-mail]; [e-mail]
>>>Sent: Tuesday, September 2, 2008 2:24:26 PM
>>>Subject: RE: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>question)
>>>
>>>Igor,
>>>
>>>Several years ago when OSPF was first proposed as an autodiscovery 
>>>mechanism for L1VPNs, you were told that it was a bad idea 
>due to its 
>>>scaling properties and impact on the IGP.
>>>
>>>You are now tacitly agreeing with those who told you it was a
>>bad idea.
>>>
>>>For your suggested approach to work with sufficient redundancy, the 
>>>topology of the overlay needs to be configured such that
>>every selected
>>>P router is connected to at least two other selected P routers and 
>>>every PE router needs to be connected to at least two selected P 
>>>routers.
>>>
>>>When you are done with this configuration, you are left with a 
>>>situation in which *every* PE and selected P router will have
>>>*all* L1VPN routes.
>>>
>>>Thanks,
>>>
>>>John
>>>
>>>>-----Original Message-----
>>>>From: Igor Bryskin [mailto:[e-mail]]
>>>>Sent: Friday, August 29, 2008 12:10 PM
>>>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>>>Cc: Yakov Rekhter; Adrian Farrel; [e-mail]; 
>>>>[e-mail]
>>>>Subject: Re: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>>question)
>>>>
>>>>Are you calling me silly? Are you coming to Minneapolis? :=)
>>>>
>>>>Seriously, what is wrong in your opinion with this approach? 
>>>>Many people are talking about multi-instance IGPs. What 
>they have in 
>>>>mind is improving the IGP scalability:
>>>>a) by removing non-IP advertisements from the instance of IGP that 
>>>>manages IP routing/forwarding tables into separate IGP instance(s);
>>>>b) by distributing non-IP information only to and via
>>>inerested parties
>>>>leaving the bulk of Ps out of the process.
>>>>
>>>>In my opinion this is exactly what is needed for the
>>OSPF-based L1VPN
>>>>application.
>>>>
>>>>Igor
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>----- Original Message ----
>>>>From: "Drake, John E" <[e-mail]>
>>>>To: Igor Bryskin <[e-mail]>; Yakov Rekhter 
>>>><[e-mail]>; Lou Berger <[e-mail]>
>>>>Cc: Yakov Rekhter <[e-mail]>; Adrian Farrel 
>>>><[e-mail]>; [e-mail]; [e-mail]
>>>>Sent: Friday, August 29, 2008 2:31:36 PM
>>>>Subject: RE: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>>question)
>>>>
>>>>So you are proposing an OSPF route reflector?  At what point
>>does the
>>>>silliness stop?
>>>>
>>>>>-----Original Message-----
>>>>>From: Igor Bryskin [mailto:[e-mail]]
>>>>>Sent: Friday, August 29, 2008 11:29 AM
>>>>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>>>>Cc: Yakov Rekhter; Adrian Farrel; [e-mail]; 
>>>>>[e-mail]
>>>>>Subject: Re: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>>>question)
>>>>>
>>>>>Hi John,
>>>>>
>>>>>No, not really. When you add a PE you configure local
>>>>interfaces, local
>>>>>VPN port mappings, stuff like that. While doing this you will also 
>>>>>configure an IPinIP tunnel to one of your spoke Ps and 
>enable L1VPN 
>>>>>OSPF instance on the tunnel.
>>>>>Once you did that the local VPN information will be flooded
>>>>accross the
>>>>>overlay, likewise, the new PE will get all the necessary
>>information
>>>>>from other PEs.
>>>>>
>>>>>Cheers,
>>>>>Igor
>>>>>
>>>>>
>>>>>----- Original Message ----
>>>>>From: "Drake, John E" <[e-mail]>
>>>>>To: Igor Bryskin <[e-mail]>; Yakov Rekhter 
>>>>><[e-mail]>; Lou Berger <[e-mail]>
>>>>>Cc: Yakov Rekhter <[e-mail]>; Adrian Farrel 
>>>>><[e-mail]>; [e-mail]; [e-mail]
>>>>>Sent: Friday, August 29, 2008 11:20:16 AM
>>>>>Subject: RE: [Softwires] BGP TE attr last call by softwires WG (2nd
>>>>>question)
>>>>>
>>>>>Igor,
>>>>>
>>>>>Doesn't this defeat auto-discovery?  I.e., how is a new PE
>>>added to a
>>>>>given L1VPN?
>>>>>
>>>>>Thanks,
>>>>>
>>>>>John
>>>>>
>>>>>>-----Original Message-----
>>>>>>From: Igor Bryskin [mailto:[e-mail]]
>>>>>>Sent: Friday, August 29, 2008 5:51 AM
>>>>>>To: Yakov Rekhter; Lou Berger
>>>>>>Cc: Yakov Rekhter; Adrian Farrel; [e-mail]; 
>>>>>>[e-mail]
>>>>>>Subject: Re: [Softwires] BGP TE attr last call by 
>softwires WG (2nd
>>>>>>question)
>>>>>>
>>>>>>Yakov,
>>>>>>
>>>>>>You said:
>>>>>>
>>>>>>
>>>>>>... And while on the subject of scaling, please keep in mind
>>>>that BGP
>>>>>>only stores L1VPN routes on PEs that have sites of that VPN
>>>>connected
>>>>>>to them, and on an RR if used, but *not* on any of the P
>>>routers. In
>>>>>>contrast, rfc5252 (OSPF for L1VPN
>>>>>>autodiscovery) results in storing *all VPN TE information
>>>for all the
>>>>>>VPNs* on *all* the IGP nodes, both P and PE. So, clearly 
>BGP-based 
>>>>>>approach scales better than OSPF-based approach.
>>>>>>
>>>>>>Yakov.
>>>>>>
>>>>>>This is not true in case of multi-instance OSPF: one can build an 
>>>>>>overlay interconnecting PEs via one or small number of Ps
>>>>>using IPinIP
>>>>>>tunnels and run in this overlay an instance of OSPF specifically 
>>>>>>designated for distribution of L1VPN information. In this
>>>>>case the OSPF
>>>>>>solution won't scale any worse than the BGP approach. Note. 
>>>>>that rfc252
>>>>>>never said that the instance of OSPF used for flooding of
>>the L1VPN
>>>>>>information must be the same instance that is used for the
>>>>>distribution
>>>>>>of IP-related LSAs.
>>>>>>
>>>>>>Regards,
>>>>>>Igor
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
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