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<p style="margin: 0 0 1em 0; color: black;">It'll pass whatever label is
passed on registration. I can send an example...</p>
<p style="margin: 0 0 1em 0; color: black;">Lou</p>
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<p
style="color: black; font-size: 10pt; font-family: Arial, sans-serif; margin: 10pt 0;">On
March 27, 2017 4:32:04 PM Marc Sune <marc@voltanet.io> wrote:</p>
<blockquote type="cite" class="gmail_quote"
style="margin: 0 0 0 0.75ex; border-left: 1px solid #808080; padding-left: 0.75ex;">
<div dir="ltr">Hi all,<div><br></div><div>Kind of an aside question about
MPLS implementation in FRR;</div><div class="gmail_extra"><br><div
class="gmail_quote">On Mon, Mar 20, 2017 at 5:38 PM, Thomas Morin <span
dir="ltr"><<a href="mailto:thomas.morin@orange.com"
target="_blank">thomas.morin@orange.com</a>></span>
wrote:<br><blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div
class="m_-8542252114825369793m_2978769784644366954moz-cite-prefix">Hi
everyone,<br>
<br>
2017-03-18, Vincent Jardin:<br>
</div><span>
<blockquote type="cite">
<div style="color:black">
<div style="color:black">
<p style="margin:0 0 1em 0;color:black">+Thomas to be on
track.</p>
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</blockquote>
<br></span>
Vincent, you'll tell if what is below helped or not :)<span><br>
<br>
<blockquote type="cite">
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<p
style="color:black;font-size:10pt;font-family:Arial,sans-serif;margin:10pt 0">
Le 18 mars 2017 06:19:47 Vivek Venkatraman
<a
class="m_-8542252114825369793m_2978769784644366954moz-txt-link-rfc2396E"
href="mailto:vivek@cumulusnetworks.com"
target="_blank"><vivek@cumulusnetworks.com></a> a écrit :</p>
<blockquote type="cite" class="gmail_quote"
style="margin:0 0 0 0.75ex;border-left:1px solid #808080;padding-left:0.75ex">
<div dir="ltr">This is correct. By definition, if a router
is the penultimate hop, it means the actual egress is
downstream and has signaled (advertised) an implicit-null
label to this router. The router doing the PHP knows the
next hop to forward to (the egress) without doing any
additional lookup.
</div>
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<br></span>
(Note that with BGP/MPLS VPNs this is the typical behavior, but it
is not a mandatory behavior: the egress router may have advertise a
real label (i.e. not implicit null) in which case the penultimate
router will swap the topmost label of the stack, not seeing/touching
the vpn label. This is also a behavior that relates to the use of
MPLS for transit, but with MPLS-over-GRE or MPLS-over-UDP, MPLS can
be used with IP transit, in which case this behavior is not
used).</div></blockquote><div><br></div><div>In regular MPLS processing (no
SR), does FRR currently support advertising any label other than implicit
NULL for MPLS traffic termination(itself)? And for
L2VPNs?</div><div><br></div><div>thanks</div><div>Marc</div><div> </div><blockquote
class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div
bgcolor="#FFFFFF" text="#000000"><span><br>
<br>
<blockquote type="cite">
<div style="color:black">
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<blockquote type="cite" class="gmail_quote"
style="margin:0 0 0 0.75ex;border-left:1px solid #808080;padding-left:0.75ex">
<div dir="ltr">
<div><br>
</div>
<div>This behavior should already be supported.</div>
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<br></span>
Yes, I can confirm that forwarding via a neighbor on an interface
based on the incoming MPLS label is supported.<br>
This is what we use in bagpipe IP VPN 'linux' driver [1].<span><br>
<br>
<blockquote type="cite">
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<blockquote type="cite" class="gmail_quote"
style="margin:0 0 0 0.75ex;border-left:1px solid #808080;padding-left:0.75ex">
<div dir="ltr">
<div><br>
</div>
<div>What is not supported (if I remember right) is the
ability on the egress to terminate a label and perform a
(route) lookup. That is needed to really be able to
support any L2/L3 VPN service properly.</div>
</div>
</blockquote>
</div>
</div>
</blockquote>
<br></span>
I think it is a requirement to have something efficient to trigger a
lookup in any {routing table, vrf interface, netns}.<br>
<br>
I hadn't tried (because no need). I thought we might achieve
something like that by forwarding the packet on 'lo', or on a vrf
interface, or on a veth device: wouldn't this kind of next hop
specification trigger a re-enter of the packet in the IP stack after
the pop operation ?<br>
<br>
-Thomas<br>
<br>
[1]
<a class="m_-8542252114825369793m_2978769784644366954moz-txt-link-freetext"
href="http://git.openstack.org/cgit/openstack/networking-bagpipe/tree/networking_bagpipe/bagpipe_bgp/vpn/ipvpn/mpls_linux_dataplane.py#n194"
target="_blank">http://git.openstack.org/cgit/<wbr>openstack/networking-bagpipe/t<wbr>ree/networking_bagpipe/bagpipe<wbr>_bgp/vpn/ipvpn/mpls_linux_<wbr>dataplane.py#n194</a><div><div
class="m_-8542252114825369793h5"><br>
<br>
<br>
<br>
<blockquote type="cite">
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<div style="color:black">
<blockquote type="cite" class="gmail_quote"
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Mar 16, 2017 at 10:45 AM,
Jeff Tantsura <span dir="ltr">
<<a href="mailto:jefftant@gmail.com"
target="_blank">jefftant@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Donald,<br>
<br>
Wrt PHP, this is incorrect, PHP node MUST not perform
IP lookup, or in fact any lookup after POP. In most
cases (labeled services, L2/L3 VPN) there's another
label(s) in the stack, looking it up would be fatal.<br>
<br>
Regards,<br>
Jeff<br>
<br>
> On Mar 15, 2017, at 08:05, Donald Sharp <<a
href="mailto:sharpd@cumulusnetworks.com"
target="_blank">sharpd@cumulusnetworks.com</a>>
wrote:<br>
><br>
> David/Roopa -<br>
><br>
> Olivier asked me about these two issues yesterday
in the FRR Technical<br>
> Meeting. I just wanted to make sure I didn't
loose track of these<br>
> questions that he had:<br>
><br>
> 1) More than 2 labels in the kernel at a time,
when will this be<br>
> allowed in the kernel?<br>
><br>
> -> David is currently working on this
issue. When he is done it<br>
> will be upstreamed. So soonish(tm).<br>
><br>
> 2) PenUltimate Hop Popping:<br>
><br>
> I know this issue is not trivial to solve. In
fact, once the POP<br>
> instruction perform, the packet must re-enter in
the IP packet<br>
> processing to determine what action must apply. A
possible solution<br>
> would be to process this packet as a new incoming
IP packet when<br>
> output interface is the loopback disregarding the
IP address value.<br>
> But, this issue is less urgent than the first
one. Our OSPF Segment<br>
> Routing implementation could announce if the
router works in<br>
> PenUltimate Hop Poping mode or not. So, for the
moment, the option is<br>
> force to yes.<br>
><br>
> thanks!<br>
><br>
> donald<br>
><br>
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