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

From: Igor Bryskin <[email-masked]>
Date: Wed, 3 Sep 2008 06:47:28 -0700 (PDT)

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" <[email-masked]>
To: Igor Bryskin <[email-masked]>; Yakov Rekhter <[email-masked]>; Lou Berger <[email-masked]>
Cc: Yakov Rekhter <[email-masked]>; Adrian Farrel <[email-masked]>; [email-masked]; [email-masked]
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:[email-masked]] 
>Sent: Tuesday, September 02, 2008 3:06 PM
>To: Drake, John E; Yakov Rekhter; Lou Berger
>Cc: Yakov Rekhter; Adrian Farrel; [email-masked]; 
>[email-masked]
>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" <[email-masked]>
>To: Igor Bryskin <[email-masked]>; Yakov Rekhter 
><[email-masked]>; Lou Berger <[email-masked]>
>Cc: Yakov Rekhter <[email-masked]>; Adrian Farrel 
><[email-masked]>; [email-masked]; [email-masked]
>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:[email-masked]]
>>Sent: Friday, August 29, 2008 12:10 PM
>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>Cc: Yakov Rekhter; Adrian Farrel; [email-masked]; 
>>[email-masked]
>>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" <[email-masked]>
>>To: Igor Bryskin <[email-masked]>; Yakov Rekhter 
>><[email-masked]>; Lou Berger <[email-masked]>
>>Cc: Yakov Rekhter <[email-masked]>; Adrian Farrel 
>><[email-masked]>; [email-masked]; [email-masked]
>>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:[email-masked]]
>>>Sent: Friday, August 29, 2008 11:29 AM
>>>To: Drake, John E; Yakov Rekhter; Lou Berger
>>>Cc: Yakov Rekhter; Adrian Farrel; [email-masked]; 
>>>[email-masked]
>>>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" <[email-masked]>
>>>To: Igor Bryskin <[email-masked]>; Yakov Rekhter 
>>><[email-masked]>; Lou Berger <[email-masked]>
>>>Cc: Yakov Rekhter <[email-masked]>; Adrian Farrel 
>>><[email-masked]>; [email-masked]; [email-masked]
>>>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:[email-masked]]
>>>>Sent: Friday, August 29, 2008 5:51 AM
>>>>To: Yakov Rekhter; Lou Berger
>>>>Cc: Yakov Rekhter; Adrian Farrel; [email-masked]; 
>>>>[email-masked]
>>>>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
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>
>

---

From: Yakov Rekhter <[email-masked]>
Date: Wed, 03 Sep 2008 06:55:49 -0700

Igor,

> If you just simply interconnect all VPN-aware PEs into a single
> ring via IPin IP 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.

Since you asked, one problem with using OSPF, as John correctly
pointed out, is that you are left with a situation in which *every* PE 
router will have *all* L1VPN routes for all the L1VPNs. Of course, 
this is "perfect" in a sense that you can do no worse than that :-)

Yakov.
  
> --0-1141253910-1220449648=:97601
> Content-Type: text/html; charset=us-ascii
> 
> <html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><
body><div style="font-family:times new roman, new york, times, serif;font-size:
12pt"><div>And I am not arguing that sufficient redundancy must be provided. Ho
wever you said:<br>&gt;For your suggested approach to work with sufficient <br>
&gt;redundancy, the topology of the overlay needs to be configured <br>&gt;such
 that every selected P router is connected to at least two <br>&gt;other select
ed P routers and every PE router needs to be <br>&gt;connected to at least two 
selected P routers.<br><br>If you just simply interconnect all VPN-aware PEs in
to a single ring via IPinIP tunnels and run an instance of OSPF to distribute V
PN-related information between them, it will provide sufficient redundancy and 
involve exactly *zero* Ps.<br>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 per
fect fo the L1VPN
>  application. Otherwise, I am not interested in this discussion any longer. I
 do like to hear comments from other people.<br><br>Igor <br><br></div><div sty
le="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><d
iv style="font-family: arial,helvetica,sans-serif; font-size: 13px;">----- Orig
inal Message ----<br>From: "Drake, John E" &lt;[email-masked]&gt;<br>
To: Igor Bryskin &lt;[email-masked]&gt;; Yakov Rekhter &lt;[email-masked]
et&gt;; Lou Berger &lt;[email-masked]&gt;<br>Cc: Yakov Rekhter &lt;yakov@juni
per.net&gt;; Adrian Farrel &lt;[email-masked]&gt;; [email-masked]; sof
[email-masked]<br>Sent: Wednesday, September 3, 2008 8:10:07 AM<br>Subject: RE
: [Softwires] BGP TE attr last call by softwires WG (2nd question)<br><br>
> Igor,<br><br>Actually, I am not sure that you do understand what I wrote, bec
ause you<br>are providing examples of the redundancy that I specified - every P
E<br>router needs to have connectivity to two other routers in the IGP<br>insta
nce.<br><br>Thanks,<br><br>John <br><br>&gt;-----Original Message-----<br>&gt;F
rom: Igor Bryskin [mailto:<a ymailto="mailto:[email-masked]" href="mailto:
[email-masked]">[email-masked]</a>] <br>&gt;Sent: Tuesday, September 
02, 2008 3:06 PM<br>&gt;To: Drake, John E; Yakov Rekhter; Lou Berger<br>&gt;Cc:
 Yakov Rekhter; Adrian Farrel; <a ymailto="mailto:[email-masked]" href="mai
lto:[email-masked]">[email-masked]</a>; <br>&gt;<a ymailto="mailto:soft
[email-masked]" href="mailto:[email-masked]">[email-masked]</a><br>&gt;
Subject: Re: [Softwires] BGP TE attr last call by softwires WG <br>&gt;(2nd que
stion)<br>&gt;<br>&gt;Hi John,<br>&gt;<br>&gt;I understand what you are saying 
and disagree. The
>  overlay I <br>&gt;am talking about logically is a separate network and as an
y <br>&gt;network it should be sufficiently redundant to function. There <br>&g
t;is a number of ways how you can address the redundancy <br>&gt;concerns. Look
 at the examples below:<br>&gt;<br>&gt;a) interconnect all VPN-aware PEs into a
 single ring: <br>&gt;PE=======PE<br>&gt; ||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
&nbsp; &nbsp; &nbsp; &nbsp; ||<br>&gt;PE&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbs
p; &nbsp;  PE <br>&gt;||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
 &nbsp;  ||<br>&gt;PE&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  PE <br>&
gt;||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  ||<br>&gt;
...&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ....<br>&gt;PE======
=PE<br>&gt;<br>&gt;b) connect each PE to two interconnected Ps <br>&gt;<br>&gt;
PE&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  P&nbsp; &nbsp; &nbsp; &nbsp
; &nbsp; &nbsp; &nbsp;
>  &nbsp;  PE<br>&gt;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &n
bsp; &nbsp; ||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  <
br>&gt;PE&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  ||&nbsp; &nbsp; &nbs
p; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; PE <br>&gt;&nbsp; &nbsp; &nbsp; &n
bsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ||&nbsp; &nbsp; &nbsp; &nbsp; &n
bsp; &nbsp; &nbsp; &nbsp; &nbsp; <br>&gt;PE&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &
nbsp; &nbsp;  ||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 
PE <br>&gt;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp
; ||&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <br>&gt;...&
nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  ||&nbsp; &nbsp; &nbsp; 
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;  ....<br>&gt;PE&nbsp; &nbsp; &nbsp; &
nbsp; &nbsp; &nbsp; &nbsp;  P&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &
nbsp; 
>  PE<br>&gt;<br>&gt;<br>&gt;Note that tunnels can traverse any number of VPN-u
naware Ps and PEs.<br>&gt;<br>&gt;Igor<br>&gt;<br>&gt;<br>&gt;----- Original Me
ssage ----<br>&gt;From: "Drake, John E" &lt;<a ymailto="mailto:John.E.Drake2@bo
eing.com" href="mailto:[email-masked]">[email-masked]</a>&g
t;<br>&gt;To: Igor Bryskin &lt;<a ymailto="mailto:[email-masked]" href="ma
ilto:[email-masked]">[email-masked]</a>&gt;; Yakov Rekhter <br>&gt;&l
t;<a ymailto="mailto:[email-masked]" href="mailto:[email-masked]">yakov@j
uniper.net</a>&gt;; Lou Berger &lt;<a ymailto="mailto:[email-masked]" href="m
ailto:[email-masked]">[email-masked]</a>&gt;<br>&gt;Cc: Yakov Rekhter &lt;<
a ymailto="mailto:[email-masked]" href="mailto:[email-masked]">yakov@juni
per.net</a>&gt;; Adrian Farrel <br>&gt;&lt;<a ymailto="mailto:[email-masked].
uk" href="mailto:[email-masked]">[email-masked]</a>&gt;; <a
>  ymailto="mailto:[email-masked]" href="mailto:[email-masked]">ccamp@o
ps.ietf.org</a>; <a ymailto="mailto:[email-masked]" href="mailto:softwires@
ietf.org">[email-masked]</a><br>&gt;Sent: Tuesday, September 2, 2008 2:24:2
6 PM<br>&gt;Subject: RE: [Softwires] BGP TE attr last call by softwires WG <br>
&gt;(2nd question)<br>&gt;<br>&gt;Igor,<br>&gt;<br>&gt;Several years ago when O
SPF was first proposed as an <br>&gt;autodiscovery mechanism for L1VPNs, you we
re told that it was <br>&gt;a bad idea due to its scaling properties and impact
 on the IGP.<br>&gt;<br>&gt;You are now tacitly agreeing with those who told yo
u it was a bad idea.<br>&gt;<br>&gt;For your suggested approach to work with su
fficient <br>&gt;redundancy, the topology of the overlay needs to be configured
 <br>&gt;such that every selected P router is connected to at least two <br>&gt
;other selected P routers and every PE router needs to be <br>&gt;connected to 
at least two selected
>  P routers.<br>&gt;<br>&gt;When you are done with this configuration, you are
 left with a <br>&gt;situation in which *every* PE and selected P router will h
ave <br>&gt;*all* L1VPN routes.<br>&gt;<br>&gt;Thanks,<br>&gt;<br>&gt;John <br>
&gt;<br>&gt;&gt;-----Original Message-----<br>&gt;&gt;From: Igor Bryskin [mailt
o:<a ymailto="mailto:[email-masked]" href="mailto:[email-masked]">i_b
[email-masked]</a>]<br>&gt;&gt;Sent: Friday, August 29, 2008 12:10 PM<br>&gt;
&gt;To: Drake, John E; Yakov Rekhter; Lou Berger<br>&gt;&gt;Cc: Yakov Rekhter; 
Adrian Farrel; <a ymailto="mailto:[email-masked]" href="mailto:[email-masked]
tf.org">[email-masked]</a>; <br>&gt;&gt;<a ymailto="mailto:[email-masked]
rg" href="mailto:[email-masked]">[email-masked]</a><br>&gt;&gt;Subject:
 Re: [Softwires] BGP TE attr last call by softwires WG (2nd <br>&gt;&gt;questio
n)<br>&gt;&gt;<br>&gt;&gt;Are you calling me silly? Are you coming to Minneapol
is?
>  :=)<br>&gt;&gt;<br>&gt;&gt;Seriously, what is wrong in your opinion with thi
s approach? <br>&gt;&gt;Many people are talking about multi-instance IGPs. What
 they have in <br>&gt;&gt;mind is improving the IGP scalability:<br>&gt;&gt;a) 
by removing non-IP advertisements from the instance of IGP that <br>&gt;&gt;man
ages IP routing/forwarding tables into separate IGP instance(s);<br>&gt;&gt;b) 
by distributing non-IP information only to and via <br>&gt;inerested parties <b
r>&gt;&gt;leaving the bulk of Ps out of the process.<br>&gt;&gt;<br>&gt;&gt;In 
my opinion this is exactly what is needed for the OSPF-based L1VPN <br>&gt;&gt;
application.<br>&gt;&gt;<br>&gt;&gt;Igor<br>&gt;&gt;<br>&gt;&gt;<br>&gt;&gt;<br
>&gt;&gt;<br>&gt;&gt;<br>&gt;&gt;<br>&gt;&gt;----- Original Message ----<br>&gt
;&gt;From: "Drake, John E" &lt;<a ymailto="mailto:[email-masked]" hre
f="mailto:[email-masked]">[email-masked]</a>&gt;<br>&gt;&gt
;To: Igor Bryskin
>  &lt;<a ymailto="mailto:[email-masked]" href="mailto:[email-masked]
">[email-masked]</a>&gt;; Yakov Rekhter <br>&gt;&gt;&lt;<a ymailto="mailto
:[email-masked]" href="mailto:[email-masked]">[email-masked]</a>&gt;; 
Lou Berger &lt;<a ymailto="mailto:[email-masked]" href="mailto:[email-masked]
et">[email-masked]</a>&gt;<br>&gt;&gt;Cc: Yakov Rekhter &lt;<a ymailto="mailt
o:[email-masked]" href="mailto:[email-masked]">[email-masked]</a>&gt;;
 Adrian Farrel <br>&gt;&gt;&lt;<a ymailto="mailto:[email-masked]" href="ma
ilto:[email-masked]">[email-masked]</a>&gt;; <a ymailto="mailto:ccamp
@ops.ietf.org" href="mailto:[email-masked]">[email-masked]</a>; <a ymai
lto="mailto:[email-masked]" href="mailto:[email-masked]">softwires@ietf
.org</a><br>&gt;&gt;Sent: Friday, August 29, 2008 2:31:36 PM<br>&gt;&gt;Subject
: RE: [Softwires] BGP TE attr last call by softwires WG (2nd
>  <br>&gt;&gt;question)<br>&gt;&gt;<br>&gt;&gt;So you are proposing an OSPF ro
ute reflector?&nbsp; At what point does the <br>&gt;&gt;silliness stop?<br>&gt;
&gt;<br>&gt;&gt;&gt;-----Original Message-----<br>&gt;&gt;&gt;From: Igor Bryski
n [mailto:<a ymailto="mailto:[email-masked]" href="mailto:i_bryskin@yahoo.
com">[email-masked]</a>]<br>&gt;&gt;&gt;Sent: Friday, August 29, 2008 11:2
9 AM<br>&gt;&gt;&gt;To: Drake, John E; Yakov Rekhter; Lou Berger<br>&gt;&gt;&gt
;Cc: Yakov Rekhter; Adrian Farrel; <a ymailto="mailto:[email-masked]" href=
"mailto:[email-masked]">[email-masked]</a>; <br>&gt;&gt;&gt;<a ymailto=
"mailto:[email-masked]" href="mailto:[email-masked]">[email-masked]
</a><br>&gt;&gt;&gt;Subject: Re: [Softwires] BGP TE attr last call by softwires
 WG (2nd<br>&gt;&gt;&gt;question)<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;Hi John,<br>&g
t;&gt;&gt;<br>&gt;&gt;&gt;No, not really. When you add a PE you configure
>  local<br>&gt;&gt;interfaces, local<br>&gt;&gt;&gt;VPN port mappings, stuff l
ike that. While doing this you will also <br>&gt;&gt;&gt;configure an IPinIP tu
nnel to one of your spoke Ps and enable L1VPN <br>&gt;&gt;&gt;OSPF instance on 
the tunnel.<br>&gt;&gt;&gt;Once you did that the local VPN information will be 
flooded<br>&gt;&gt;accross the<br>&gt;&gt;&gt;overlay, likewise, the new PE wil
l get all the necessary information <br>&gt;&gt;&gt;from other PEs.<br>&gt;&gt;
&gt;<br>&gt;&gt;&gt;Cheers,<br>&gt;&gt;&gt;Igor<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;
<br>&gt;&gt;&gt;----- Original Message ----<br>&gt;&gt;&gt;From: "Drake, John E
" &lt;<a ymailto="mailto:[email-masked]" href="mailto:John.E.Drake2@b
oeing.com">[email-masked]</a>&gt;<br>&gt;&gt;&gt;To: Igor Bryskin &lt
;<a ymailto="mailto:[email-masked]" href="mailto:[email-masked]">i_br
[email-masked]</a>&gt;; Yakov Rekhter <br>&gt;&gt;&gt;&lt;<a ymailto="mailto:y
[email-masked]"
>  href="mailto:[email-masked]">[email-masked]</a>&gt;; Lou Berger &lt;<a
 ymailto="mailto:[email-masked]" href="mailto:[email-masked]">lberger@labn.
net</a>&gt;<br>&gt;&gt;&gt;Cc: Yakov Rekhter &lt;<a ymailto="mailto:yakov@junip
er.net" href="mailto:[email-masked]">[email-masked]</a>&gt;; Adrian Farre
l <br>&gt;&gt;&gt;&lt;<a ymailto="mailto:[email-masked]" href="mailto:adri
[email-masked]">[email-masked]</a>&gt;; <a ymailto="mailto:[email-masked]
.org" href="mailto:[email-masked]">[email-masked]</a>; <a ymailto="mail
to:[email-masked]" href="mailto:[email-masked]">[email-masked]</a><
br>&gt;&gt;&gt;Sent: Friday, August 29, 2008 11:20:16 AM<br>&gt;&gt;&gt;Subject
: RE: [Softwires] BGP TE attr last call by softwires WG (2nd<br>&gt;&gt;&gt;que
stion)<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;Igor,<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;Does
n't this defeat auto-discovery?&nbsp; I.e., how is a new PE <br>&gt;added to a 
<br>&gt;&gt;&gt;given
>  L1VPN?<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;Thanks,<br>&gt;&gt;&gt;<br>&gt;&gt;&gt
;John<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;-----Original Message-----<br>&gt;&gt;
&gt;&gt;From: Igor Bryskin [mailto:<a ymailto="mailto:[email-masked]" href
="mailto:[email-masked]">[email-masked]</a>]<br>&gt;&gt;&gt;&gt;Sent:
 Friday, August 29, 2008 5:51 AM<br>&gt;&gt;&gt;&gt;To: Yakov Rekhter; Lou Berg
er<br>&gt;&gt;&gt;&gt;Cc: Yakov Rekhter; Adrian Farrel; <a ymailto="mailto:ccam
[email-masked]" href="mailto:[email-masked]">[email-masked]</a>; <br>&g
t;&gt;&gt;&gt;<a ymailto="mailto:[email-masked]" href="mailto:softwires@iet
f.org">[email-masked]</a><br>&gt;&gt;&gt;&gt;Subject: Re: [Softwires] BGP T
E attr last call by softwires WG (2nd<br>&gt;&gt;&gt;&gt;question)<br>&gt;&gt;&
gt;&gt;<br>&gt;&gt;&gt;&gt;Yakov,<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;You sa
id:<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;... And while on
 the subject of
>  scaling, please keep in mind<br>&gt;&gt;that BGP<br>&gt;&gt;&gt;&gt;only sto
res L1VPN routes on PEs that have sites of that VPN<br>&gt;&gt;connected<br>&gt
;&gt;&gt;&gt;to them, and on an RR if used, but *not* on any of the P <br>&gt;r
outers. In <br>&gt;&gt;&gt;&gt;contrast, rfc5252 (OSPF for L1VPN<br>&gt;&gt;&gt
;&gt;autodiscovery) results in storing *all VPN TE information <br>&gt;for all 
the<br>&gt;&gt;&gt;&gt;VPNs* on *all* the IGP nodes, both P and PE. So, clearly
 BGP-based <br>&gt;&gt;&gt;&gt;approach scales better than OSPF-based approach.
<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;Yakov.<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&
gt;&gt;This is not true in case of multi-instance OSPF: one can build an <br>&g
t;&gt;&gt;&gt;overlay interconnecting PEs via one or small number of Ps<br>&gt;
&gt;&gt;using IPinIP<br>&gt;&gt;&gt;&gt;tunnels and run in this overlay an inst
ance of OSPF specifically <br>&gt;&gt;&gt;&gt;designated for distribution of L1
VPN information. In
>  this<br>&gt;&gt;&gt;case the OSPF<br>&gt;&gt;&gt;&gt;solution won't scale an
y worse than the BGP approach. Note. <br>&gt;&gt;&gt;that rfc252<br>&gt;&gt;&gt
;&gt;never said that the instance of OSPF used for flooding of the L1VPN <br>&g
t;&gt;&gt;&gt;information must be the same instance that is used for the<br>&gt
;&gt;&gt;distribution<br>&gt;&gt;&gt;&gt;of IP-related LSAs.<br>&gt;&gt;&gt;&gt
;<br>&gt;&gt;&gt;&gt;Regards,<br>&gt;&gt;&gt;&gt;Igor<br>&gt;&gt;&gt;&gt;<br>&g
t;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;&gt;<br>&gt;&gt;&gt;<br>&gt;&
gt;&gt;<br>&gt;&gt;&gt;<br>&gt;&gt;&gt;<br>&gt;&gt;<br>&gt;&gt;<br>&gt;&gt;<br>
&gt;<br>&gt;<br>&gt;<br>&gt;<br><br></div></div></div><br>
> 
>       </body></html>
> --0-1141253910-1220449648=:97601--

---

From: "Drake, John E" <[email-masked]>
Date: Wed, 3 Sep 2008 07:01:29 -0700

Igor,

I'm sorry, but you were the one that stipulated P routers.  I mentioned
the more general requirement in my last e-mail:  "every PE router needs
to have connectivity to two other routers in the IGP instance".

The points being that:

1) The configuration burden is twice what you claimed it to be.

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.

Thanks,

John  

>Sent: Wednesday, September 03, 2008 6:47 AM
>>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 
>
>
>
>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 
>
>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:
>>
>>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.
>>
>>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.
>>

---

From: "Tony Li" <[email-masked]>
Date: Wed, 3 Sep 2008 10:25:51 -0700

I do like to hear comments from other people. 

OSPF (and any other flooding based protocol) is a particularly poor basis
for doing restricted dissemination of information.  The only way to
constrain the flooding is to constrain the topology, which adds an
additional layer of management overhead that is simply unnecessary.
 
Tony

---

From: Lou Berger <[email-masked]>
Date: Wed, 03 Sep 2008 13:39:27 -0400

>I do like to hear comments from other people.

IMO this discussion (OSPF and BGP applicability and limitations wrt 
L1VPNs) was sufficiently covered in the l1vpn WG, and nothing being 
said now changes the fundamental arguments or conclusions of that discussion.

Lou

PS  PLEASE feel free to drop me from the to/cc line of this thread!