Subject: [rbridge] draft-ietf-trill-rbridge-oam-02

From: somnath chatterjee <[email-masked]>
Date: Wed, 21 Mar 2012 17:11:29 +0530

Hi Authors,

1>In Section 4.1.1 two  statements can be found which is ambiguous.
In first paragraph
"The M bit MUST be zero."
and in sixth paragraph
"The M bit MUST be zero for a known unicast ping."

I think the ping tool should not be limited to unicast use only and
should be allowed to be sent on distribution tree when used for
multidestination frames/unknown unicast. It would be good to include
excerpts from draft-yizhou-trill-multi-destination-ping in this OAM
draft which talks about multi-destination ping, jitters etc.

2> It would be good if RBridges that implement TRILL- OAM does not
decrement Hop count by more than one for OAM/Channel messages only.
This would help us limiting the max hop count used for traceroute to
be equal to the diameter of the campus.

3> If my understanding is correct there is no way to distinguish
between pings reply and unicast traceroute reply(other than the error
replies). An user may use both the tool concurrently or with minimal
time gap. As such it would be hard to distinguish between the replies
only with sequence number. I would suggest to use some unique
identifier to differentiate between the two types of messages.

4> In Section 4.1.2.1
". . . various forms of ECMP hashing based on fields such as MAC
addresses, IP addresses, and/or TCP/UDP port numbers."
 Vlans may be added to the fields list.

5> In Section 4.1.2.2
Editorial changes for "One cannot use the diemater of the network . .
."  should be replaced by
"One cannot use the diameter of the network/campus"

Thank you,
Regards,
Somnath
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From: David M Bond <[email-masked]>
Date: Wed, 21 Mar 2012 09:41:33 -0400

Hello Somnath,

Thanks for the comments. My responses are inline below with [DBOND].

Thanks,
David

From:	somnath chatterjee <[email-masked]>
To:	[email-masked]
Date:	03/21/2012 07:58 AM
Subject:	[rbridge]  draft-ietf-trill-rbridge-oam-02
Sent by:	[email-masked]

Hi Authors,

[DBOND] Agreed. In fact I have been talking with Yizhou about merging these
two drafts but I have not had a chance yet. One item that did come up that
is useful to mention is in relation to jitter. Currently in Yizhou's draft
she has an alternative format for echos so that the time stamp is in a
fixed offset for hardware. If at all possible I would prefer to have a
single format for echos. My idea was to say time stamps are TLVs but if
they appear they MUST always be the first TLV in the TLV list. This way
they have a fixed location in the packet so hardware could work with them.
Could some hardware folks comment on the viability of this? In general I
see there being three options here:

  Alternative Format Echo with TimeStamp
  Change Base Format of Echo to include TimeStamp
  Fixed location of TimeStamp TLV

What does everyone in the WG think?
[/DBOND]

[DBOND] To do this there would have to be separate logic for TRILL OAM
messages. It is very important that OAM frames follow the same logic as any
other frame (to test the forwarding plane) and so we can't make a special
condition as such.[/DBOND]

[DBOND] I'm unsure why the sequence number would be insufficient to meet
this need. Please elaborate.

4> In Section 4.1.2.1

[DBOND] Adding

5> In Section 4.1.2.2

[DBOND] Adding

Thank you,
Regards,
Somnath

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From: somnath chatterjee <[email-masked]>
Date: Wed, 21 Mar 2012 22:49:14 +0530

Hi David,

Please ignore my 3rd point regarding sequence numbers, I missed the
random/arbitrary generation of sequence numbers in the draft. With
random generation of 28bits sequence number the probability of
collision tends to zero.

Thank you,
Regards,
Somnath