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From: =?UTF-8?B?VHXhuqVuIEFuaCBWxak=?= <anhvt.hdg@gmail.com>
Date: Tue, 22 Oct 2024 10:44:38 +0700
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 <CA+SXWCnrL-0AbHKJo_k0RNhVP-maJQqkwfdaZfx4wo82eKYO=w@mail.gmail.com>
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Subject: =?utf-8?q?=5Bmpls=5D_Comments_abount_rfc2205_Resource_ReSerVation_Protocol_?=
	=?utf-8?q?=28RSVP=29?=
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 <https://mailarchive.ietf.org/arch/msg/mpls/2yu5YOVMSWbpwFDUUkd3reqr2jM>

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Hi IETF team,
I'm AnhVT from the SVTech company in VietNam, I have experienced some RSVP
issues in the IPv4 MPLS network.
I suspect that RSVP has a point that needs to be enhanced. I describe this
point below:

I./ Topology:
    ---------LSP-------->
    R1----R2----R3-----R4
          |    /
          |  /
           R5
II./ Issue
1./ Because of some bugs (exp: R3 experiences a flap link between R3-R2,
but R2 does not recognize the interface flap), R3 indicates that LSP is
down, then it deletes the LSP state and sends the PathTear downstream to R4.
2./Because R2 does not recognize the interface flap, R2 still keeps it
 available. It does not know that the LSP should be deleted.
3./ Due to 1./ and 2./ R1 does not know that the LSP is stuck because R3
and R4 deleted the LSP state, and R1 continues forwarding traffic to the
LSP, This makes the service down.

III./ My comment
I think that RSVP needs a mechanic so that R3 signals to R2 to ensure that
R2 knows that R3 deleted the LSP. Based on that signal, R2 will bring down
the LSP and continue to send Reserve Tear to R1.

I hope that you take a look at my comment.

Regards,
AnhVT

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<div dir=3D"ltr">Hi IETF team,<div>I&#39;m AnhVT from the SVTech company in=
 VietNam, I have experienced=C2=A0some RSVP issues in the IPv4 MPLS network=
.</div><div>I suspect that RSVP has a point that needs to be enhanced. I de=
scribe=C2=A0this point below:</div><div><br></div><div>I./ Topology:</div><=
div><font face=3D"monospace">=C2=A0 =C2=A0 ---------LSP--------&gt;</font><=
/div><div><font face=3D"monospace">=C2=A0 =C2=A0 R1----R2----R3-----R4</fon=
t></div><div><font face=3D"monospace">=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 |=
=C2=A0 =C2=A0 /</font></div><div><font face=3D"monospace">=C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 |=C2=A0 /</font></div><div><font face=3D"monospace">=C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0R5</font></div><div><font face=3D"ari=
al, sans-serif">II./ Issue</font></div><div><font face=3D"arial, sans-serif=
">1./ Because of some bugs (exp: R3 experiences a flap link between R3-R2, =
but R2 does not recognize the interface flap), R3 indicates that LSP is dow=
n, then it deletes the LSP state and sends the PathTear downstream to R4.</=
font></div><div><font face=3D"arial, sans-serif">2./Because R2 does not rec=
ognize the interface flap,</font><span style=3D"font-family:arial,sans-seri=
f">=C2=A0R2 still keeps it</span><span style=3D"font-family:arial,sans-seri=
f">=C2=A0available.</span><span style=3D"font-family:arial,sans-serif">=C2=
=A0It does not know that the LSP should be deleted.</span></div><div><font =
face=3D"arial, sans-serif">3./ Due to 1./ and 2./ R1 does not know that the=
 LSP is stuck because R3 and R4 deleted the LSP state, and R1 continues for=
warding traffic to the LSP, This makes the service down.</font></div><div><=
font face=3D"arial, sans-serif"><br></font></div><div><font face=3D"arial, =
sans-serif">III./ My comment</font></div><div><font face=3D"arial, sans-ser=
if">I think that RSVP needs a mechanic=C2=A0so that R3 signals to R2 to ens=
ure that R2 knows that R3 deleted the LSP. Based on that signal, R2 will br=
ing down the LSP and continue to send Reserve Tear to R1.</font></div><div>=
<font face=3D"monospace"><br></font></div><div><font face=3D"arial, sans-se=
rif">I hope that you take a look at my comment.</font></div><div><font face=
=3D"arial, sans-serif"><br></font></div><div><font face=3D"arial, sans-seri=
f">Regards,</font></div><div><font face=3D"arial, sans-serif">AnhVT</font><=
/div></div>

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