Anoop,

As Pierre says, the head-end is able to choose whether he would like protection 
from a midpoint. This assumes that one advertises both “protected” and 
“unprotected” segments within a network where there may be a requirement for 
both, allowing the head-end to select the relevant segment. This is roughly 
analogous to the behaviour of requesting FRR (or not) when signalling a TE-LSP, 
and hence has the same security characteristics from my perspective.

It should be noted that _if_ all segments are advertised as protected (and 
non-revertive/unprotected segments are not available) then this may introduce 
more detailed per-LSP OAM requirements at the head-end to ensure that it can 
react to a service which does not meet its performance constraints during a 
period where local FRR is being utilised by a midpoint on the path.

Kind regards,
r.




On 6 Jun 2014, at 15:53, Pierre Francois <[email protected]> wrote:

> 
> 
> Anoop, 
> 
> Well, we have this requirement to be able to have both approaches doable at 
> the same time on the same network... 
> 
> For example, in SR, you can encode configure your segments as to be 
> protected, or not. 
> 
> If you want local protection, configure segments to be locally protected. 
> If you want path protection, configure segments to not be locally protected. 
> 
> If you need both for two different services, you'd configure both types and 
> pick the ones that match the service you need. 
> 
> Cheers, 
> 
> Pierre.
> 
> 
> 
> On Jun 6, 2014, at 4:45 PM, Anoop Ghanwani <[email protected]> wrote:
> 
>> Pierre,
>> 
>> My question is more from a security standpoint.
>> 
>> If a node is explicitly identified in the path and that node is down, is it 
>> OK to route around it.
>> 
>> I guess what I'm hearing you say is that it depends on what the network 
>> operator has configured.  They can choose to either discard all such 
>> packets, or route all such packets around the failure, but they cannot 
>> choose what it to be done on a per-packet basis.  Do I have that right?
>> 
>> Anoop
>> 
>> 
>> On Fri, Jun 6, 2014 at 7:38 AM, Pierre Francois <[email protected]> 
>> wrote:
>> 
>> Anoop, 
>> 
>> You loose the traffic until the moment the ingress node falls back on 
>> another path. 
>> 
>> If you don't want to have to wait for that failover to happen, then your 
>> use-case is in another section than the one using path protection ;)
>> 
>> Pierre.
>> 
>> 
>> 
>> On Jun 6, 2014, at 4:30 PM, Anoop Ghanwani <[email protected]> wrote:
>> 
>>> Thanks Pierre.
>>> 
>>> What if the failed component is one of the explicitly identified hops?
>>> 
>>> Anoop
>>> 
>>> 
>>> On Fri, Jun 6, 2014 at 5:28 AM, Pierre Francois <[email protected]> 
>>> wrote:
>>> 
>>> Hello Anoop, 
>>> 
>>> In path protection, section 2, the packets will be dropped until the 
>>> ingress node decides to stop using the failed path and failover. 
>>> 
>>> In all other sections, the packets are to be rerouted directly by the nodes 
>>> adjacent to the failed component.
>>> 
>>> Cheers, 
>>> 
>>> Pierre.
>>> 
>>> On Jun 5, 2014, at 8:51 PM, Anoop Ghanwani <[email protected]> wrote:
>>> 
>>>> I have a question about this draft.
>>>> 
>>>> In section 2, it has the following statement:
>>>> >>>
>>>> >From a SPRING viewpoint, we would like to highlight the following
>>>> requirement: the two configured paths T1 and T2 MUST NOT benefit from
>>>> local protection.
>>>> >>>
>>>> 
>>>> But there is no such statement in subsequent sections.
>>>> 
>>>> So suppose I have a data packet using SPRING to use path A - B - C.  If B 
>>>> is down, would such packets be discarded or would there be an attempt to 
>>>> get it to C if one of the other methods for repair is configured?
>>>> 
>>>> Anoop
>>>> 
>>>> On Tue, May 13, 2014 at 9:35 AM, <[email protected]> wrote:
>>>> 
>>>> A New Internet-Draft is available from the on-line Internet-Drafts 
>>>> directories.
>>>>  This draft is a work item of the Source Packet Routing in Networking 
>>>> Working Group of the IETF.
>>>> 
>>>>         Title           : Use-cases for Resiliency in SPRING
>>>>         Authors         : Pierre Francois
>>>>                           Clarence Filsfils
>>>>                           Bruno Decraene
>>>>                           Rob Shakir
>>>>         Filename        : draft-ietf-spring-resiliency-use-cases-00.txt
>>>>         Pages           : 8
>>>>         Date            : 2014-05-12
>>>> 
>>>> Abstract:
>>>>    This document describes the use cases for resiliency in SPRING
>>>>    networks.
>>>> 
>>>> 
>>>> The IETF datatracker status page for this draft is:
>>>> https://datatracker.ietf.org/doc/draft-ietf-spring-resiliency-use-cases/
>>>> 
>>>> There's also a htmlized version available at:
>>>> http://tools.ietf.org/html/draft-ietf-spring-resiliency-use-cases-00
>>>> 
>>>> 
>>>> Please note that it may take a couple of minutes from the time of 
>>>> submission
>>>> until the htmlized version and diff are available at tools.ietf.org.
>>>> 
>>>> Internet-Drafts are also available by anonymous FTP at:
>>>> ftp://ftp.ietf.org/internet-drafts/
>>>> 
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>>> 
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