Subject: Re: [Isis-wg] Last Call: draft-ietf-isis-bfd-tlv (IS-IS BFD EnabledTLV) to Proposed Standard

From: "lan7801" <[email-masked]>
Date: Mon, 26 Jul 2010 17:04:40 +0800

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.
 To avoid confusion,it is better to specify that the IS-IS must triggere BFD session establishment before the adjacency is in UP state.
 
 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.

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
[email-masked] mailing lists by 2010-07-26. Exceptionally, 
comments may be sent to [email-masked] 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
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