doubt in Figure 5 of RFC 2328

Mani Devarajan <mani_devarajan@NET.COM> Mon, 23 June 2003 19:20 UTC

Received: from cherry.ease.lsoft.com (cherry.ease.lsoft.com [209.119.0.109]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id PAA06098 for <ospf-archive@LISTS.IETF.ORG>; Mon, 23 Jun 2003 15:20:15 -0400 (EDT)
Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <14.00A2BC78@cherry.ease.lsoft.com>; Mon, 23 Jun 2003 15:16:57 -0400
Received: from PEACH.EASE.LSOFT.COM by PEACH.EASE.LSOFT.COM (LISTSERV-TCP/IP release 1.8e) with spool id 46357931 for OSPF@PEACH.EASE.LSOFT.COM; Mon, 23 Jun 2003 15:16:42 -0400
Received: from 134.56.3.131 by WALNUT.EASE.LSOFT.COM (SMTPL release 1.0i) with TCP; Mon, 23 Jun 2003 15:06:37 -0400
Received: from mx01-int.net.com (mx01-int.net.com [134.56.112.13]) by mx01.net.com (Switch-2.2.5/Switch-2.2.5) with ESMTP id h5NJ8Hb17449 for <OSPF@PEACH.EASE.LSOFT.COM>; Mon, 23 Jun 2003 12:08:17 -0700 (PDT)
Received: from west-mail.net.com (west-mail.net.com [134.56.112.40]) by mx01-int.net.com (Switch-2.2.4/Switch-2.2.4) with ESMTP id h5NJ8Hi08763 for <OSPF@PEACH.EASE.LSOFT.COM>; Mon, 23 Jun 2003 12:08:17 -0700 (PDT)
Received: from net.com ([134.56.216.89]) by west-mail.net.com (Netscape Messaging Server 4.15) with ESMTP id HGY7SE00.IL6 for <OSPF@PEACH.EASE.LSOFT.COM>; Mon, 23 Jun 2003 12:07:26 -0700
X-Mailer: Mozilla 4.61C-NETv45 [en] (X11; U; SunOS 5.7 sun4u)
X-Accept-Language: en, en-GB, fr, de
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Message-ID: <3EF74F8A.22F92D39@net.com>
Date: Mon, 23 Jun 2003 12:05:46 -0700
Reply-To: Mailing List <OSPF@PEACH.EASE.LSOFT.COM>
Sender: Mailing List <OSPF@PEACH.EASE.LSOFT.COM>
From: Mani Devarajan <mani_devarajan@NET.COM>
Organization: N.E.T. http://www.net.com
Subject: doubt in Figure 5 of RFC 2328
To: OSPF@PEACH.EASE.LSOFT.COM
Precedence: list
Content-Transfer-Encoding: 7bit

Hi all,

In the figure 5 of rfc 2328 "The SPF tree for Router RT6",
there is an extra node between N9 and RT9.

Does that node mean something,or it has been added intentionally.

                                              |   |
                                           N9 o   o N7
                                             /|
                                            / |
                        N11      RT9       /  |RT12
                         o--------o-------o   o--------o H1
                             3                |   10
                                              |2
                                              |
                                              o N10

Thanks,
Mani