Re: [Idr] draft-bashandy-idr-bgp-repair-label-01: when does PE revert back to standard label?

[Robert Raszuk <[e-mail]>]

Jakob,

>>> PE1 gets no new update from PE2, therefore will continue to use the
>>> repair label to PE2.
>>
>> No update is required to be received from PE2. Loosing PE1's directly
>> attached path and recalculating all information already present in
>> control plane is already sufficient.
>
> That causes the repair label to be used towards PE2.

No. You need to realize that control plane trigger is not equal to data 
plane trigger. Those are two totally separate message paths with 
different forwarding outcome.

Any sort of FRR uses data plane/forwarding event to trigger really fast 
prefix independent switchover (usually less then 50ms) to a backup path.

However control plane is much slower. But will eventually in 100s of ms 
converge completely removing the original directly connected best path 
and it's protection via PE2.

It is really very simple.

>>> Ahmed clarified it for me like this: If PE1 receives a packet
>>> destined for a prefix advertised by CE, PE1 will push the primary
>>> label advertised by the primary egress PE (be it PE2 or any
>> other PE)
>>> and then tunnel the packet to that PE.
>>
>> Yes, but only after the local control plane convergence happens.
>
> Not necessary.

;)

>> Nope. It does not matter what type of packets are received.
>> Described in the other (non orthogonal) mail.
>
> Not described.
> Please read carefully and understand before answering.

I did, but apparently my answer was a little bit implicit but I hoped 
you will parse it. So let me try again ...

The draft says black on white:

"and associate a local label with each prefix such as L3VPN [9], 6PE 
[10], and Softwire [8]"

it directly means to me that as written it is not applicable to IPv4 and 
IPv6 non mpls protection.

And as suggested that can be fixed extending the scope of the draft to 
make it applicable also to unicast IPv4 and IPv6 as this is not only 
safe, but also desired in mpls networks where best external is injected.

R.