From: Dr. Seuss (greeneggsandham4@hotmail.com)
Date: Wed Jan 14 2009 - 21:50:47 ARST
Well here's what I ended up doing:
router isis
redistribute bgp 20
summary-address 0.0.0.0 0.0.0.0 level-1 metric 13 *just some weird-looking
number to make it stand out
I was sort of surprised by the results. The level-1 routers in the area
received only a default route, and when I looked in R6's ISIS database, none
of the individual BGP routes appeared - just the static route.
Here's the ISIS database on R6 when I just redistributed BGP and did nothing
else:
sho isis database detail
[snip]
Router6.00-00 * 0x00000018 0xCBCB 1182 0/0/0 Area
Address: 49.0002 NLPID: 0x81 0xCC Hostname: Router6 IP Address:
6.6.6.6 Metric: 10 IP 35.1.0.0 255.255.255.0 Metric: 10 IP
6.6.6.6 255.255.255.255 Metric: 10 IS RouterBB3.02 Metric: 0
ES Router6 Metric: 33 IP-External 1.1.1.1 255.255.255.255 Metric: 33
IP-External 2.2.2.2 255.255.255.255 Metric: 33 IP-External 5.5.5.5
255.255.255.255 Metric: 33 IP-External 11.0.0.0 255.0.0.0 Metric: 33
IP-External 46.1.0.0 255.255.255.0 Metric: 33 IP-External 49.1.0.0
255.255.255.0
[snip]
Now here's the R6 ISIS database when I'm redistributing BGP *and* using the
summary address:
sho isis database detail
Router6.00-00 * 0x00000017 0xA2FF 1015 0/0/0 Area
Address: 49.0002 NLPID: 0x81 0xCC Hostname: Router6 IP Address:
6.6.6.6 Metric: 10 IP 35.1.0.0 255.255.255.0 Metric: 10 IP
6.6.6.6 255.255.255.255 Metric: 10 IS RouterBB3.02 Metric: 0
ES Router6 Metric: 13 IP-External 0.0.0.0 0.0.0.0
So, pretty cool - it doesn't choke the ISIS database with all the BGP routes,
and informs the router that it's fulfilling the role of an ASBR, so to speak.
Friday will be my *third* attempt at the BSCI...failed it by a hair last time.
ISIS was one of my weak spots (28%!), so hopefully I can tame this beast now.
Thanks,
BJW> Date: Wed, 14 Jan 2009 15:27:43 -0500> From: nilsi2002@gmail.com> To:
greeneggsandham4@hotmail.com> Subject: Re: ISIS default routes> CC:
ccielab@groupstudy.com> > I'm not sure if this is the most elegant method but
it seems to work.> > Take your step 2)> > On your Router6> > router isis> net
xx.xxxx> summary-address 0.0.0.0 0.0.0.0 level-1> redistribute static ip
metric 50 level-1> > > -Rich> > > > On Wed, Jan 14, 2009 at 9:01 AM, Dr. Seuss
<greeneggsandham4@hotmail.com> wrote:> > I've been playing around with default
routes in ISIS the last couple of days,> > and I've searched through the
archives for more info. My topology is simple:> > Router6 is a L1/L2 router
with an ethernet connection to Router8, and a> > frame-relay connection to
Router2. R6 and R2 speak BGP with each other, and> > R6 speaks ISIS with R8.
I'm trying to get R6 to feed a default route to R8> > (redistributing BGP into
ISIS is a bad idea), and here's what I've discovered> > so far:> >> > 1) R6
does *not* automatically set the ATT bit in its LSP updates to R8,> > despite
R6 being L1/L2 and R8 being L1.> >> > 2) Configuring a static route to null0
on the L1/L2 router and redistributing> > static does not work. L1 routers
(R8) do not receive a default route.> >> > 3) Configuring a static route to
null0 on the L1/L2 router and using> > "default-information originate" does
not work. L1 routers do not receive a> > default route.> >> > 4) Configuring
ISIS between R6 and R2 *does* impel R6 to send a default route> > to R8. This
is the *only* configuration so far which gets a default route> > into R8's
routing table.> >> > For the record, R8 is running 12.1(3r)T2, and R6 is
running Version 12.2(8r).> > My question is this: what is the ISIS equivalent
of an ASBR? It doesn't seem> > to want to feed a default route to anyone else
unless it's attached to another> > *ISIS* area!> >> > Thanks,> > BJW> >> >
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