Re: WG LC draft-ietf-idr-flowspec-path-redirect-10.txt [11/17/2019 to 12/2/2019]

Robert Raszuk <[email protected]> Tue, 3 Dec 2019 15:20:53 +0100
Newsgroups gmane.ietf.idr
Message-ID <CAOj+MMGpiDtW-HRahyFWLHag0MoqHLeEMFsNsEMtc3E=DyAwRQ@mail.gmail.com>
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Hey Gunter,

> That means we keep current proposed Type 0 and Type 5
> (and rename Type 5 to something more sensible in that case).

Yes and that would be a great fix.

To sort of cover more explicitly then via type 0 types 2,3 & 4 you may
define new type to carry the "color". The same color as carried in BGP SR
Policy document if you want to be SR friendly :).

Then we should be fine.

Cheers,
R.,

On Tue, Dec 3, 2019 at 11:20 AM Van De Velde, Gunter (Nokia - BE/Antwerp) <
[email protected]> wrote:

> BGP SR policy is different in such a way that it can not steer based upon
> a flowspec tupple match. It uses a payload prefix and NH to select a
> particular path policy.
>
>
>
> The original path-redirect had no additional assumptions associated and i=
t
> referenced a 32bit number (Type 0 Seq-ID).
>
> This 32bit number was used as opaque value to lookup forwarding
> information. If enabled, this is what I have in running code.
>
>
>
>
>
> ***
>
>    ID-Type: 1 octet value.  This draft defines following Context Types:
>
>
>
>       0 - Localised ID (The flowspec client uses the received 32-bit
>
>       indirection-id to lookup forwarding information within the
>
>       localised indirection-id table.  The allocation and programming of
>
>       the localised indirection-id table is outside scope of the
>
>       document)
>
>
>
>       1 - Node ID with SID/index in MPLS-based Segment Routing (This
>
>       means the 32-bit indirection-id is mapped to an MPLS label using
>
>       the index as a global offset in the SID/label space)
>
>
>
>       2 - Node ID with SID/label in MPLS-based Segment Routing (This
>
>       means the 32-bit indirection-id is mapped to an MPLS label using
>
>       the 32-bit indirection-id as global label)
>
>
>
>       3 - Binding Segment ID with SID/index in MPLS-based Segment
>
>       Routing (This means the 32-bit indirection-id is mapped to an MPLS
>
>       binding label using the indirection-id as index for global offset
>
>       in the SID/label space) [I-D.draft-ietf-spring-segment-routing]
>
>       [6]
>
>
>
>       4 - Binding Segment ID with SID/label in MPLS-based Segment
>
>       Routing (This means 32-bit indirection-id is mapped to an MPLS
>
>       binding label using the 32-bit indirection-id as global label) [I-
>
>       D.draft-ietf-spring-segment-routing] [6]
>
>
>
>       5 - Tunnel ID (Tunnel ID is within a single administrative domain
>
>       a 32-bit globally unique tunnel identifier.  The allocation and
>
>       programming of the Tunnel ID within the localised indirection-id
>
>       table is outside scope of the document)
>
>
>
>    Generalized indirection_id: 32-bit identifier used as indirection_id
>
>
>
> ***
>
>
>
> I do have sympathy for your suggestion to simplify assuming if the genera=
l
> WG feels that there is too much overlap between the BGP SR Policy
> propagation and the current indirection Type 1, 2, 3, 4? We could drop
> those Type=E2=80=99s from the current draft and simplify interop complexi=
ty? That
> means we keep current proposed Type 0 and Type 5 (and rename Type 5 to
> something more sensible in that case).
>
>
>
> G/
>
>
>
> *From:* Robert Raszuk <[email protected]>
> *Sent:* Monday, December 2, 2019 19:30
> *To:* Jeffrey Haas <[email protected]>; Van De Velde, Gunter (Nokia -
> BE/Antwerp) <[email protected]>
> *Cc:* [email protected]; Sue Hares <[email protected]>
> *Subject:* Re: [Idr] WG LC draft-ietf-idr-flowspec-path-redirect-10.txt
> [11/17/2019 to 12/2/2019]
>
>
>
>
>
> I suspect in the majority of the cases that path-redirect is intended
> involving segment routing that following a segment path from a VRF contex=
t
> doesn't make much sense.  However, some of the cases are left as much mor=
e
> abstract and perhaps they could?
>
>
>
> IMO using flow spec extension to specify a binding SID which in turn will
> be replaced by explicit path is a huge mistake this draft is proposing.
> Sure text can take everything but the operational complexity to
> troubleshoot such network will be a nightmare. And if you would just
> specify a single SID why not to specify the IP address and be done ? Rout=
er
> will reach such IP via proper path.
>
>
>
> Please observe that you are now trying to mimic BGP SR Policy propagation
> which also includes mapping via color and policy to be used.
>
>
>
> What happens when router will receive both in a conflicting manner ?
>
>
>
> Btw what practical application is this draft trying to accomplish other
> then pretty badly redo subset of BGP SR Policy work ?
>
>
>
> Thx,
> R/
>
>
>

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<div dir=3D"ltr">Hey Gunter,<div><br></div><div>&gt; That means we keep cur=
rent proposed Type 0 and Type 5=C2=A0</div><div>&gt; (and rename Type 5 to =
something more sensible in that case).=C2=A0=C2=A0<br></div><div><br></div>=
<div>Yes and that would be a great fix.=C2=A0</div><div><br></div><div>To s=
ort of cover more explicitly=C2=A0then via type 0 types 2,3 &amp; 4 you may=
 define new type to carry the &quot;color&quot;. The same color as carried =
in BGP SR Policy document if you want to be SR friendly :).=C2=A0</div><div=
><br></div><div>Then we should be fine.=C2=A0</div><div><br></div><div>Chee=
rs,</div><div>R.,</div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr=
" class=3D"gmail_attr">On Tue, Dec 3, 2019 at 11:20 AM Van De Velde, Gunter=
 (Nokia - BE/Antwerp) &lt;<a href=3D"mailto:[email protected]">=
[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"=
gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(20=
4,204,204);padding-left:1ex">





<div lang=3D"EN-US">
<div class=3D"gmail-m_-6760708744570272191WordSection1">
<p class=3D"MsoNormal">BGP SR policy is different in such a way that it can=
 not steer based upon a flowspec tupple match. It uses a payload prefix and=
 NH to select a particular path policy.<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">The original path-redirect had no additional assumpt=
ions associated and it referenced a 32bit number (Type 0 Seq-ID).<u></u><u>=
</u></p>
<p class=3D"MsoNormal">This 32bit number was used as opaque value to lookup=
 forwarding information. If enabled, this is what I have in running code.<u=
></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">***<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0 ID-Type: 1 octet value.=C2=A0 This draf=
t defines following Context Types:<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0 - Localised ID (The=
 flowspec client uses the received 32-bit<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 indirection-id to loo=
kup forwarding information within the<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 localised indirection=
-id table.=C2=A0 The allocation and programming of<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 the localised indirec=
tion-id table is outside scope of the<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 document)<u></u><u></=
u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 1 - Node ID with SID/=
index in MPLS-based Segment Routing (This<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 means the 32-bit indi=
rection-id is mapped to an MPLS label using<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 the index as a global=
 offset in the SID/label space)<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 2 - Node ID with SID/=
label in MPLS-based Segment Routing (This<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 means the 32-bit indi=
rection-id is mapped to an MPLS label using<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 the 32-bit indirectio=
n-id as global label)<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 3 - Binding Segment I=
D with SID/index in MPLS-based Segment<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Routing (This means t=
he 32-bit indirection-id is mapped to an MPLS<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 binding label using t=
he indirection-id as index for global offset<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 in the SID/label spac=
e) [I-D.draft-ietf-spring-segment-routing]<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 [6]<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 4 - Binding Segment I=
D with SID/label in MPLS-based Segment<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 Routing (This means 3=
2-bit indirection-id is mapped to an MPLS<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 binding label using t=
he 32-bit indirection-id as global label) [I-<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 D.draft-ietf-spring-s=
egment-routing] [6]<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 5 - Tunnel ID (Tunnel=
 ID is within a single administrative domain<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 a 32-bit globally uni=
que tunnel identifier.=C2=A0 The allocation and<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 programming of the Tu=
nnel ID within the localised indirection-id<u></u><u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 table is outside scop=
e of the document)<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">=C2=A0=C2=A0 Generalized indirection_id: 32-bit iden=
tifier used as indirection_id<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">***<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">I do have sympathy for your suggestion to simplify a=
ssuming if the general WG feels that there is too much overlap between the =
BGP SR Policy propagation and the current indirection Type 1, 2, 3, 4? We c=
ould drop those Type=E2=80=99s from the current
 draft and simplify interop complexity? That means we keep current proposed=
 Type 0 and Type 5 (and rename Type 5 to something more sensible in that ca=
se).<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal">G/<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<p class=3D"MsoNormal"><b>From:</b> Robert Raszuk &lt;<a href=3D"mailto:rob=
[email protected]" target=3D"_blank">[email protected]</a>&gt; <br>
<b>Sent:</b> Monday, December 2, 2019 19:30<br>
<b>To:</b> Jeffrey Haas &lt;<a href=3D"mailto:[email protected]" target=3D"_bl=
ank">[email protected]</a>&gt;; Van De Velde, Gunter (Nokia - BE/Antwerp) &lt;=
<a href=3D"mailto:[email protected]" target=3D"_blank">gunter.v=
[email protected]</a>&gt;<br>
<b>Cc:</b> <a href=3D"mailto:[email protected]" target=3D"_blank">[email protected]</=
a>; Sue Hares &lt;<a href=3D"mailto:[email protected]" target=3D"_blank">shar=
[email protected]</a>&gt;<br>
<b>Subject:</b> Re: [Idr] WG LC draft-ietf-idr-flowspec-path-redirect-10.tx=
t [11/17/2019 to 12/2/2019]<u></u><u></u></p>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
<div>
<div>
<div>
<p class=3D"MsoNormal">=C2=A0<u></u><u></u></p>
</div>
<blockquote style=3D"border-top:none;border-right:none;border-bottom:none;b=
order-left:1pt solid rgb(204,204,204);padding:0in 0in 0in 6pt;margin-left:4=
..8pt;margin-right:0in">
<p class=3D"MsoNormal">I suspect in the majority of the cases that path-red=
irect is intended<br>
involving segment routing that following a segment path from a VRF context<=
br>
doesn&#39;t make much sense.=C2=A0 However, some of the cases are left as m=
uch more<br>
abstract and perhaps they could?<u></u><u></u></p>
</blockquote>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
<div>
<p class=3D"MsoNormal">IMO using flow spec extension to specify a binding S=
ID which in turn will be replaced by explicit path is a huge mistake this d=
raft is proposing. Sure text can take everything but the operational comple=
xity to troubleshoot such network
 will be a nightmare. And if you would just specify a single SID why not to=
 specify the=C2=A0IP address and be done ? Router will reach such IP via pr=
oper path.<u></u><u></u></p>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
<div>
<p class=3D"MsoNormal">Please observe that you are now trying to mimic BGP =
SR Policy propagation which also includes mapping via color and policy to b=
e used.=C2=A0<u></u><u></u></p>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
<div>
<p class=3D"MsoNormal">What happens when router will receive both in a conf=
licting manner ?=C2=A0<u></u><u></u></p>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
<div>
<p class=3D"MsoNormal">Btw what practical application is this draft trying =
to accomplish other then pretty badly redo subset of BGP SR Policy work=C2=
=A0?=C2=A0<u></u><u></u></p>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
<div>
<p class=3D"MsoNormal">Thx,<br>
R/<u></u><u></u></p>
</div>
<div>
<p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p>
</div>
</div>
</div>
</div>
</div>

</blockquote></div>

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