(Stewart - thanx for calling this to our attention)
Jiaxing -
Sorry for the delayed response, but as you did not copy the IS-IS WG your post
was not seen.
Responses inline.
-----Original Message-----
From: isis-wg-bounces(_at_)ietf(_dot_)org
[mailto:isis-wg-bounces(_at_)ietf(_dot_)org] On
Behalf Of Stewart Bryant (stbryant)
Sent: Friday, September 03, 2010 12:19 PM
To: isis-wg
Subject: [Isis-wg] Fwd: Re: Last Call: draft-ietf-isis-bfd-tlv (IS-IS
BFD EnabledTLV) to Proposed Standard
This LC comment only appeared on the main IETF list
Please will the authors address this issue
-------- Original Message --------
Subject: Re: [Isis-wg] Last Call: draft-ietf-isis-bfd-tlv (IS-IS BFD
EnabledTLV) to Proposed Standard
Date: Mon, 26 Jul 2010 17:04:40 +0800
From: lan7801 <lan7801(_at_)gmail(_dot_)com>
<mailto:lan7801(_at_)gmail(_dot_)com>
To: ietf <ietf(_at_)ietf(_dot_)org> <mailto:ietf(_at_)ietf(_dot_)org>
CC: iesg <iesg(_at_)ietf(_dot_)org> <mailto:iesg(_at_)ietf(_dot_)org>
Hi,
I have some comments about this draft.
section 3.2. Adjacency Establishment and Maintenance
Whenever ISIS_BFD_REQUIRED is TRUE the following extensions to
the
rules for adjacency establishment and maintenance MUST apply:
o ISIS_NEIGHBOR_USEABLE MUST be TRUE before the adjacency can
transition from INIT to UP state
This rule assumes that both the BFD and IS-IS configurations are
correct and they work well. But This isn't the way all
the time.
AS we know that the establishment of the BFD session is bootstraped
by IS-IS,If the BFD enabled interface have two or
more address, which address should be used to create the BFD session ?
If the two addresses of the BFD session are not on
the same subnet,the BFD session will fail ,and the IS-IS adjacency can
never be ceated.That is a risk.
Cisco router encodes the primary ip address of the inteface in IS-IS
hello's ip interface address(es) TLV, however,Juniper
router encodes all addresses of the interface in ip interface
address(es) TLV,How about the other router ?
To resove this problem,this draft should specify which address should
be used .The choosed address may be included in the
BFD enabled TLV.
I am reluctant to add this option to the TLV. Local configuration is required
to specify which IP address should be used in cases where multiple addresses
are configured on the interface. If there is a mismatch between what is
configured on two neighbors then having the advertisement will not help us
insure that matching subnets are used - so it seems that we have not made life
any easier/better by adding this information in the TLV.
To avoid confusion,it is better to specify that the IS-IS must
triggere BFD session establishment before the adjacency is in UP state.
The point of the draft is to REQUIRE that the BFD session be UP before the
IS-IS adjacency transitions to UP - but only when it is known that BFD is
enabled on both neighbors. This avoids failure to bring up an adjacency simply
because of mismatched configurations (i.e. one IS has BFD support and the other
does not).
There is another scenario we must consider. When the state of IS-IS
adjacency is UP and the administrator trys to configure BFD or modify
BFD configuration, IS-IS should discard the first BFD session failure
,IS-IS can trust BFD session state only after
BFD session has informed IS-IS a BFD session success.
This point is addressed in Section 4 of the draft.
Les
________________________________
Jiaxing Lan
2010-07-25
________________________________
发件人： The IESG
发送时间： 2010-07-13 02:42:14
收件人： IETF-Announce
抄送： isis-wg
主题： [Isis-wg] Last Call: draft-ietf-isis-bfd-tlv (IS-IS BFD
EnabledTLV) to Proposed Standard
The IESG has received a request from the IS-IS for IP Internets WG
(isis)
to consider the following document:
- 'IS-IS BFD Enabled TLV '
<draft-ietf-isis-bfd-tlv-02.txt> as a Proposed Standard
The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action. Please send substantive comments to the
ietf(_at_)ietf(_dot_)org mailing lists by 2010-07-26. Exceptionally,
comments may be sent to iesg(_at_)ietf(_dot_)org instead. In either case,
please
retain the beginning of the Subject line to allow automated sorting.
The file can be obtained via
http://www.ietf.org/internet-drafts/draft-ietf-isis-bfd-tlv-02.txt
IESG discussion can be tracked via
https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag
=17118&rfc_flag=0
_______________________________________________
Isis-wg mailing list
Isis-wg(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/isis-wg
_______________________________________________
Ietf mailing list
Ietf(_at_)ietf(_dot_)org
https://www.ietf.org/mailman/listinfo/ietf