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BOUNCE ccamp@ops.ietf.org: Non-member submission from [MichaelMandelberg <mmandelberg@lopsys.com>] (fwd)
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- Subject: BOUNCE ccamp@ops.ietf.org: Non-member submission from [MichaelMandelberg <mmandelberg@lopsys.com>] (fwd)
- From: Kireeti Kompella <kireeti@juniper.net>
- Date: Tue, 15 Jul 2003 06:10:57 -0700 (PDT)
Message from a non-subscriber.
---------- Forwarded message ----------
From: Michael Mandelberg <mmandelberg@lopsys.com>
To: ccamp@ops.ietf.org
Cc: "'lberger@movaz.com'" <lberger@movaz.com>
Subject: Please help me to resolve this ambiguity in the RSVP_HOP object
usage defined in rfc3473 (GMPLS extensions for RSVP-TE)
Date: Sun, 6 Jul 2003 23:35:07 -0400
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>From Section 8.1 I get:
The choice of the data interface to use is always made by the
sender<?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" />
of the Path message. The choice of the data interface is indicated by
the sender of the Path message by including the data channel's
interface identifier in the message using a new RSVP_HOP object sub-
type. For bidirectional LSPs, the sender chooses the data interface
in each direction. In all cases but bundling, the upstream interface
is implied by the downstream interface. For bundling, the path
sender explicitly identifies the component interface used in each
direction. The new RSVP_HOP object is used in Resv message to
indicate the downstream node's usage of the indicated interface(s).
Suppose that LSR A sends a PATH message to LSR B, and later LSR B sends a
RESERVE message to LSR A. From all this I gather that:
1) in the PATH message LSR A puts the 32-bit interface identifier(s) into
the RSVP_HOP object.
2) These identifiers are those configured on the LSR A. In other words, when
LSR B processes the PATH message, it will have to look up the mapping to
determine its local identifiers for these interfaces.
3) The last sentence in the quoted paragraph susggests that the RSVP_HOP
object in the RESERVE message should reference the interfaces using
identifiers configured on LSR B, so that when LSR A receives the RESERVE
message, it will have to look up the mapping to determine its local
identifiers for these interfaces.
Now, from Section 8.1.2:
A node receiving one or more TLVs in a Path message saves their
values and returns them in the HOP objects of subsequent Resv
messages sent to the node that originated the TLVs.
This paragraph implies the opposite of point 3) above. It says that the
RSVP_HOP object in the RESERVE message sent by LSR B should contain the
*same* values as those it received.
There is a clear ambiguity, and a suggested contradiction here. What is the
intent, and what is the proper resolution?
Thanks
Michael Mandelberg
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<DIV><SPAN class=921121403-07072003><FONT face=Arial color=#0000ff size=2>From
Section 8.1 I get:</FONT></SPAN></DIV>
<DIV><SPAN class=921121403-07072003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=921121403-07072003>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT face="Courier New"><FONT
size=2><SPAN class=921121403-07072003><FONT face=Arial
color=#0000ff> </FONT></SPAN>The choice of the
data interface to use is always made by the sender<?xml:namespace prefix = o ns
= "urn:schemas-microsoft-com:office:office"
/><o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>of the
Path message. The choice of the data interface is indicated
by<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>the
sender of the Path message by including the data
channel's<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>interface
identifier in the message using a new RSVP_HOP object
sub-<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes">
</SPAN>type.<SPAN style="mso-spacerun: yes"> </SPAN>For bidirectional
LSPs, the sender chooses the data interface<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>in each
direction.<SPAN style="mso-spacerun: yes"> </SPAN>In all cases but
bundling, the upstream interface<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>is
implied by the downstream interface.<SPAN style="mso-spacerun: yes">
</SPAN>For bundling, the path<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>sender
explicitly identifies the component interface used in
each<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes">
</SPAN>direction.<SPAN style="mso-spacerun: yes"> </SPAN>The new RSVP_HOP
object is used in Resv message to<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"><SPAN style="mso-spacerun: yes"> </SPAN>indicate
the downstream node's usage of the indicated
interface(s).<o:p></o:p></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"> </FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT size=2><FONT
face="Courier New"></FONT></FONT></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN class=921121403-07072003>Suppose that LSR A sends a
PATH message to LSR B, and later LSR B sends a RESERVE message to LSR A. From
all this I gather that:</SPAN></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN class=921121403-07072003>1) in the PATH message
LSR A puts the 32-bit interface identifier(s) into the RSVP_HOP
object.</SPAN></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN class=921121403-07072003>2) These identifiers are
those configured on the LSR A. In other words, when LSR B processes the PATH
message, it will have to look up the mapping to determine its local identifiers
for these interfaces.</SPAN></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN class=921121403-07072003>3) The last sentence in the
quoted paragraph susggests that the RSVP_HOP object in the RESERVE message
should reference the interfaces using identifiers configured on LSR B, so that
when LSR A receives the RESERVE message, it will have to look up the mapping to
determine its local identifiers for these
interfaces.</SPAN></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN class=921121403-07072003>Now, from Section
8.1.2:</SPAN></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff size=2><SPAN
class=921121403-07072003></SPAN></FONT></FONT></SPAN> </P><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT><FONT face=Arial
color=#0000ff><SPAN class=921121403-07072003>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT color=#000000><FONT
face="Courier New"><FONT size=2><SPAN style="mso-spacerun: yes">
</SPAN>A node receiving one or more TLVs in a Path message saves
their<o:p></o:p></FONT></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT color=#000000><FONT
face="Courier New"><FONT size=2><SPAN style="mso-spacerun: yes">
</SPAN>values and returns them in the HOP objects of subsequent
Resv<o:p></o:p></FONT></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
style="mso-fareast-font-family: 'MS Mincho'"><FONT color=#000000><FONT
face="Courier New"><FONT size=2><SPAN style="mso-spacerun: yes">
</SPAN>messages sent to the node that originated the
TLVs.<o:p></o:p></FONT></FONT></FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><FONT size=2></FONT> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003><FONT size=2>This paragraph implies the opposite of
point 3) above. It says that the RSVP_HOP object in the RESERVE message
sent by LSR B should contain the *same* values as those it
received.</FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003><FONT size=2>There is a clear ambiguity, and a
suggested contradiction here. What is the intent, and what is the proper
resolution?</FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003><FONT size=2>Thanks</FONT></SPAN></P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003></SPAN> </P>
<P class=MsoPlainText style="MARGIN: 0in 0in 0pt"><SPAN
class=921121403-07072003><FONT size=2>Michael
Mandelberg</FONT> </SPAN></SPAN></FONT></FONT></SPAN></P></SPAN></DIV></BODY></HTML>
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