From: Scott Morris (swm@emanon.com)
Date: Sun Aug 08 2004 - 15:23:21 GMT-3
I'm pretty sure that Jeff was using those extra configs in order to push a
0/0 route to the other L2 router. The ATT bit handles L1 routers in your
area, but nobody else.
I don't have his book in front of me, but I feel relatively confident that
he knows a thing or two about routing protocols. :)
If it is a mistake in the book, I'm sure we'll just blame it on the editors
anyway (grin)!!!
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIP, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
k_kaloianov@eircom.net
Sent: Sunday, August 08, 2004 11:33 AM
To: john matijevic; 'Scott Morris'; k_kaloianov@eircom.net;
ccielab@groupstudy.com
Subject: RE: isis and ATT bit=1
Thanks to both of you guys, John, Scott,
I think this clears things in my head now, your answers are exactly what I
saw while playing with isis, I was a little confused cause in TCP/IP vol.1
Jeff Doyle is suggesting this two extra configs in order for default route
to be propagated to L1 routers?
Reg,
Kaloyan
"john matijevic" <matijevi@bellsouth.net> wrote:
<
< Hello Scott,
< The default route is installed per Cisco doc.
< "A Level 1/Level 2 router that is attached to another area will set the <
"attached bit" in its Level 1 LSP; all the Level 1 ISs in an area will <
get a copy of this LSP and know where to forward packets to destinations <
outside the area. If the routers are running Integrated IS-IS, a default <
IP route will automatically be installed in the Level 1 routers pointing <
toward the nearest Level 1/Level 2 router that originally set the <
attached bit in its Level 1 LSP. A Level 1/Level 2 router that is not <
attached to another area can also detect that a Level 2-only neighbor is <
attached to another area and set the "attached bit" on behalf of this <
Level 2-only neighbor."
< I think the point of the question was if that using the command default <
information originate was necessary to install a default route. And if <
the default route being installed was normal behavior. I am just trying <
to help the individual. Unlike other companies, I don't focus on <
attacking other individuals. I focus on solutions. I don't have to take <
the exam. It is Kaloyan who has to take the exam. So it is important < that
he understands why the default route appears in the routing table.
< Here is the link for more information:
< http://www.cisco.com/en/US/tech/tk365/tk381/technologies_white_paper0918
< 6a00800a3e6f.shtml
< Team, if anyone else has any trouble understanding this, please let me <
know.
< :) Again im not here to debate, I don't like to see a lot of threads, im
< here to help.
< Sincerely,
< John Matijevic, CCIE #13254, MCSE, CNE, CCEA < Network Consultant <
Hablo Espanol < 305-321-6232 < < -----Original Message----- < From:
nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of < Scott
Morris < Sent: Sunday, August 08, 2004 10:42 AM < To: 'john matijevic';
k_kaloianov@eircom.net; ccielab@groupstudy.com < Subject: RE: isis and ATT
bit=1 < < Actually, the default route is not "sent" at all. The ATT bit
indicates < connection to an outside area. As soon as L1 routers see
routes with < the < ATT bit set, they will create a default route pointing
to the router < that < sent the ATT-bit routes.
<
< HTH,
<
<
< Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, <
CISSP, < JNCIP, et al.
< IPExpert CCIE Program Manager
< IPExpert Sr. Technical Instructor
< swm@emanon.com/smorris@ipexpert.net
< http://www.ipexpert.net
<
<
<
< -----Original Message-----
< From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of <
john < matijevic < Sent: Sunday, August 08, 2004 9:54 AM < To:
k_kaloianov@eircom.net; ccielab@groupstudy.com < Subject: RE: isis and ATT
bit=1 < < Hello Kaloyan, < What you are seeing is normal behavior with
IS-IS, basically it treats < each < level-1 router as a stub area. It will
send a default route to a < level-1 area. IF you have a level-1-2 domain
you can configure route < leaking < so that the individual routes will
show up with the default. For more < information on that see the following
link:
< http://www.cisco.com/en/US/tech/tk365/tk381/technologies_tech_note09186a
< 0080093f39.shtml
< :)
<
< Sincerely,
< John Matijevic, CCIE #13254, MCSE, CNE, CCEA Network Consultant Hablo <
Espanol < 305-321-6232 < < -----Original Message----- < From:
nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of <
k_kaloianov@eircom.net < Sent: Sunday, August 08, 2004 7:06 AM < To:
ccielab@groupstudy.com < Subject: isis and ATT bit=1 < < Hi Group, < <
just a dumb question about isis and IOS ver 12.2, I'm just having two <
areas < and one router in one area and two in the other one, the two
routers are < L1 < and L1/L2 and the other one is L2 or L2/L1, I just want
to know whether < we < have to use clns router isis command on L2/L1
iterface connecting /w L1 < router or alternatively default-information
originate and default static < route to null interface in order to
propagate default route to L1 < router?
< The behaviour that I saw was that even without any of the above <
configuration there was a default route created in L1 routing table?
< Thanks
< in advance:)
<
< Reg,
<
< Kaloyan-:)
<
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