Bruno,
Thanks for the comments. Replies below

-----Original Message-----
From: [email protected] [mailto:[email protected]] 
Sent: Monday, November 12, 2012 1:44 AM
To: Arjun Sreekantiah (asreekan)
Cc: [email protected]
Subject: draft-ymbk-l3vpn-origination-02

Arjun, all,

I confess that I don't know much about SIDR, but I guess that I'm not the only 
one in L3 VPN. Therefore clarification may be useful for the L3 VPN WG.

Let's assume that no RPKI is used.

1) Given that the goal is to protect from unintentional errors, can you 
elaborate on the added value brought by l3vpn-origination compared to the use 
of a (extended) community agreed upon the VPN sites (e.g. some kind of a shared 
password)?
The latter being available now, how much is it deployed/used now? (I would 
assume that l3vpn-origination would be used by a subset of such current users)
[Arjun] 
Please note that the scheme does provide protection against attack scenarios as 
well, this is not just protecting errors from configuration. Using a community 
or extended community makes it vulnerable in a attack scenarios. It is easy to 
figure out the community or extended community value for prefixes for that VPN 
simply by looking at the BGP update or some show command output for the prefix 
in that VPN. In the scheme, we use a digest generated from a secret (possibly 
shared ) key  and hence this is not easy to decipher. 
Also, communities (and extended communities) are not propagated across the ebgp 
boundary by default. 

2) Can you elaborate on how l3vpn-origination protects from unintentional 
errors by the legitimate originator?
Seems to me that both correct and erroneous routes would be signed by the 
egress CE/PE and hence accepted by the ingress.
[Arjun]
The idea here is to protect against routes being originated from 
unintended/unauthorized sources (similar to RPKI based prefix validation),  so 
any spurious routes sourced in transit can be detected and dealt with in the 
appropriate manner. Detecting erroneous routes  coming  from the  proper 
originator itself is beyond the scope of what is defined.

3) Given that a VPN may want to import routes from outside of the VPN (e.g. 
provider IP services (e.g. voice gateway), extranet), how does 
l3vpn-origination protect from unintentional errors from those partners?
[Arjun]
For simplicity we would recommend sharing keys with the extranet partners, 
voice gateway sources this does mean that errors originating from those sources 
will not be protected. Again we would expect these services to be trusted 
sources.

Thanks
Arjun 

Thanks for the clarifications,
Bruno

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