From: Volkov, Dmitry (Toronto - BCE) (dmitry_volkov@xxxxxxxxx)
Date: Tue Aug 20 2002 - 08:58:36 GMT-3
Yes,
Brian,
Thanks a lot for pointing us to debug and RFC ...
Looks like the explanation is in the logic of the process
of how OSPF installs external routes in RT:
1) By changing distance of EIGRP internal higher than OSPF makes route to
Forward Address: 172.16.1.1 - to be route learned via OSPF which is valid to
be installed in RT.
2) Removing ospf from e0/0 on R10 makes forwarding address "0".
So forward address has to be zero,
or if not zero it has to be in RT as OSPF O/O IA route. - Right ?
Thanks again,
Dmitry
-----Original Message-----
From: K Sarangan [mailto:K.Sarangan@cwgoindia.com]
Sent: Tuesday, August 20, 2002 4:47 AM
To: Brian Dennis; Volkov, Dmitry (Toronto - BCE); Mingzhou Nie; yakout
yakout; Colin Barber; msnyder@revolutioncomputer.com
Cc: ccielab@groupstudy.com
Subject: RE: Are EIGRP external routes preferable than OSPF ext ??
Brian,
Salute you sir. Wish you could be in bangalore and I could crack CCIE like
nuts.
thank you very much for letting us know the problem.
regards,
sarangan
-----Original Message-----
From: Brian Dennis [mailto:brian@5g.net]
Sent: Monday, August 19, 2002 12:25 PM
To: 'Volkov, Dmitry (Toronto - BCE)'; 'Mingzhou Nie'; 'yakout yakout';
'Colin Barber'; msnyder@revolutioncomputer.com
Cc: ccielab@groupstudy.com
Subject: RE: Are EIGRP external routes preferable than OSPF ext ??
It appears to be an OSPF forwarding address issue:
<RFC_2328 Section="16.4 Calculating AS external routes">'
If the forwarding address is non-zero, look up the forwarding address in
the routing table.[24] The matching routing table entry must specify an
intra-area or inter-area path; if no such path exists, do nothing with
the LSA and consider the next in the list.
</RFC_2328>
Do a "sho ip os da ex 172.16.3.0" and see what the forward address is
for that LSA. Look at your routing table and see what route the router
has to the forwarding address for the 172.16.3.0 external LSA. Now turn
on "deb ip os spf ex" and then do a "clear ip rout *" and see why it
tells you the OSPF routes aren't used.
For those without this configuration setup in their lab I've included
the commands below. Enjoy!
Brian Dennis, CCIE #2210 (R&S/ISP Dial)
R11#sho ip os da ex 172.16.3.0
OSPF Router with ID (172.16.5.1) (Process ID 10)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 2011
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 172.16.3.0 (External Network Number )
Advertising Router: 172.16.5.2
LS Seq Number: 80000002
Checksum: 0xC498
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 172.16.1.1
External Route Tag: 0
R11#sho ip route 172.16.1.1
Routing entry for 172.16.1.0/24
Known via "eigrp 10", distance 90, metric 2195456, type internal
Redistributing via eigrp 10
Last update from 172.16.5.2 on Serial1, 00:20:19 ago
Routing Descriptor Blocks:
* 172.16.5.2, from 172.16.5.2, 00:20:19 ago, via Serial1
Route metric is 2195456, traffic share count is 1
Total delay is 21000 microseconds, minimum bandwidth is 1544 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
R11#deb ip os spf ex
OSPF spf external events debugging is on
R11#clear ip rout *
R11#
RT: add 172.16.5.0/24 via 0.0.0.0, connected metric [0/0]
RT: add 172.16.4.0/24 via 172.16.5.2, eigrp metric [170/2323456]
RT: add 172.16.1.0/24 via 172.16.5.2, eigrp metric [90/2195456]
RT: add 172.16.3.0/24 via 172.16.5.2, eigrp metric [170/2323456]
OSPF: Started Building Type 5 External Routes
OSPF: Start processing Type 5 External LSA 172.16.1.0, mask
255.255.255.0, adv 172.16.5.2, age 292, seq 0x80000004, metric 20,
metric-type 2
Add better path to LSA ID 172.16.1.0, gateway 172.16.5.2, dist 20
Add path: next-hop 172.16.5.2, interface Serial1
OSPF: delete lsa id 172.16.1.0, type 5, adv rtr 172.16.5.2 from delete
list
OSPF: insert route list LS ID 172.16.1.0, type 5, adv rtr 172.16.5.2
OSPF: Start processing Type 5 External LSA 172.16.2.0, mask
255.255.255.0, adv 172.16.5.2, age 1549, seq 0x80000003, metric 20,
metric-type 2
OSPF: Fail to find route to forwarding addr 172.16.1.1
OSPF: Start processing Type 5 External LSA 172.16.3.0, mask
255.255.255.0, adv 172.16.5.2, age 1549, seq 0x80000003, metric 20,
metric-type 2
OSPF: Fail to find route to forwarding addr 172.16.1.1
OSPF: Start processing Type 5 External LSA 172.16.4.0, mask
255.255.255.0, adv 172.16.5.2, age 1549, seq 0x80000003, metric 20,
metric-type 2
OSPF: Fail to find route to forwarding addr 172.16.1.1
OSPF: Start processing Type 5 External LSA 172.16.5.0, mask
255.255.255.0, adv 172.16.5.2, age 493, seq 0x80000001, metric 20,
metric-type 2
Add better path to LSA ID 172.16.5.0, gateway 172.16.5.2, dist 20
Add path: next-hop 172.16.5.2, interface Serial1
OSPF: delete lsa id 172.16.5.0, type 5, adv rtr 172.16.5.2 from delete
list
OSPF: insert route list LS ID 172.16.5.0, type 5, adv rtr 172.16.5.2
OSPF: ex_delete_old_routes
OSPF: Started Building Type 7 External Routes
OSPF: ex_delete_old_routes
R11#
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Volkov, Dmitry (Toronto - BCE)
Sent: Sunday, August 18, 2002 8:14 PM
To: 'Mingzhou Nie'; Volkov, Dmitry (Toronto - BCE); 'yakout yakout';
Colin Barber; 'msnyder@revolutioncomputer.com'
Cc: ccielab@groupstudy.com
Subject: RE: Are EIGRP external routes preferable than OSPF ext ??
Hi,
I'm not sure, what is the matter what process put first, what - second.
As I told, I reload routers...
If it's bug - it's consistent bug:
I have 12.1(16) on R11, Colin Barber tested it with 12.1(10a)and 11.3
R11
Consistent bug - is not bug it should be called CAVEAT :)
I tried to remove ospf process and put back on R11 - once I got O E2
untill...
clear ip ro *, after that again D EX.
Please note that "distance eigrp 130 170" on R11 changes situation.
Looks like, if ext. OSPF and EIGRP routes learned from the same source,
router consider ext EIGRP routes as INTERNAL !! - This is the only
explanation I see.
Dmitry
-----Original Message-----
From: Mingzhou Nie [mailto:mnie@yahoo.com]
Sent: Sunday, August 18, 2002 10:28 PM
To: Mingzhou Nie; Volkov, Dmitry (Toronto - BCE); 'yakout yakout'; Colin
Barber
Cc: ccielab@groupstudy.com
Subject: RE: Are EIGRP external routes preferable than OSPF ext ??
And you probably entered "router eigrp" before "router ospf" on r11. If
you do reverse, you also got expected results.
This is definitely a bug in IOS.
--- Mingzhou Nie <mnie@yahoo.com> wrote:
> I tried myself. Initially, I got your results. But after doing either
> one of these, routers on r11 show as expected.
>
> - remove ospf process 10 on r11, and add back process 1
> - remove "redis igrp 10 subnets" on r10, and add it back
>
>
> r11#show ip route
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B -
> BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
>
> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS
> inter area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 172.16.0.0/24 is subnetted, 5 subnets
> O E2 172.16.4.0 [110/20] via 172.16.5.2, 00:01:47, Ethernet0/0
> C 172.16.5.0 is directly connected, Ethernet0/0
> D 172.16.1.0 [90/307200] via 172.16.5.2, 00:01:39, Ethernet0/0
> O E2 172.16.2.0 [110/20] via 172.16.5.2, 00:01:48, Ethernet0/0
> O E2 172.16.3.0 [110/20] via 172.16.5.2, 00:01:47, Ethernet0/0
> r11#
>
>
> --- "Volkov, Dmitry (Toronto - BCE)" <dmitry_volkov@ca.ml.com> wrote:
> > OK guys,
> >
> > .100, .111 and .222 - are loopbacks on R11 - It's irrelevant.
> > I just forgot to remove it from previous test :)
> > Yesterday when I got this problem I didn't have these loopbacks.
> >
> > Ok, I removed any feedback from the picture and left only one-way
> > redist on
> > R10:
> > Now R9---(igrp)---R10(redist IGRP-->OSPF,EIGRP)---R11 (OSPF, EIGRP)
> >
> > The result is the same !!! D EX routes on R11.
> > (I even reload routers :o)
> >
> > router eigrp 10
> > network 172.16.0.0
> > !
> > router ospf 10
> > redistribute igrp 10 subnets
> > network 172.16.1.0 0.0.0.255 area 0
> > network 172.16.5.0 0.0.0.255 area 0
> > !
> > router igrp 10
> > no redistribute eigrp 10
> > passive-interface Ethernet1/0
> > network 172.16.0.0
> >
> > 172.16.0.0/24 is subnetted, 8 subnets
> > C 172.16.222.0 is directly connected, Loopback2
> > D EX 172.16.4.0 [170/435200] via 172.16.5.2, 00:00:21, Ethernet0
> > C 172.16.5.0 is directly connected, Ethernet0
> > D 172.16.1.0 [90/307200] via 172.16.5.2, 00:00:21, Ethernet0
> > D EX 172.16.2.0 [170/435200] via 172.16.5.2, 00:00:21, Ethernet0
> > D EX 172.16.3.0 [170/435200] via 172.16.5.2, 00:00:21, Ethernet0
> > C 172.16.111.0 is directly connected, Loopback1
> > C 172.16.100.0 is directly connected, Loopback0
> > r11#sh ip ei
> > r11#sh ip ospf nei
> >
> > Neighbor ID Pri State Dead Time Address
> > Interface
> > 172.16.5.2 1 FULL/DR 00:00:36 172.16.5.2
> > Ethernet0
> > r11#sh ip ospf data
> >
> > OSPF Router with ID (172.16.222.1) (Process ID 10)
> >
> >
> > Router Link States (Area 0)
> >
> > Link ID ADV Router Age Seq# Checksum
> Link
> > count
> > 172.16.5.2 172.16.5.2 53 0x80000002 0xC778 2
> > 172.16.222.1 172.16.222.1 52 0x80000002 0x1538 4
> >
> > Net Link States (Area 0)
> >
> > Link ID ADV Router Age Seq# Checksum
> > 172.16.5.2 172.16.5.2 53 0x80000001 0x133F
> >
> > Type-5 AS External Link States
> >
> > Link ID ADV Router Age Seq# Checksum Tag
> > 172.16.1.0 172.16.5.2 263 0x80000001 0x9589 0
> > 172.16.2.0 172.16.5.2 145 0x80000001 0xD18D 0
> > 172.16.3.0 172.16.5.2 145 0x80000001 0xC697 0
> > 172.16.4.0 172.16.5.2 145 0x80000001 0xBBA1 0
> > 172.16.5.0 172.16.5.2 263 0x80000001 0x69B1 0
> > r11#sh ip eig
> > r11#sh ip eigrp top
> > IP-EIGRP Topology Table for AS(10)/ID(172.16.222.1)
> >
> > Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> > r - reply Status, s - sia Status
> >
> > P 172.16.222.0/24, 1 successors, FD is 128256
> > via Connected, Loopback2
> > P 172.16.4.0/24, 1 successors, FD is 435200
> > via 172.16.5.2 (435200/409600), Ethernet0
> > P 172.16.5.0/24, 1 successors, FD is 281600
> > via Connected, Ethernet0
> > P 172.16.1.0/24, 1 successors, FD is 307200
> > via 172.16.5.2 (307200/281600), Ethernet0
> > P 172.16.2.0/24, 1 successors, FD is 435200
> > via 172.16.5.2 (435200/409600), Ethernet0
> > P 172.16.3.0/24, 1 successors, FD is 435200
> > via 172.16.5.2 (435200/409600), Ethernet0
> > P 172.16.111.0/24, 1 successors, FD is 128256
> > via Connected, Loopback1
> > P 172.16.100.0/24, 1 successors, FD is 128256
> > via Connected, Loopback0
> > r11#
> > ==========
> >
> > Dmitry
> >
> > -----Original Message-----
> > From: Mingzhou Nie [mailto:mnie@yahoo.com]
> > Sent: Sunday, August 18, 2002 5:11 PM
> > To: Volkov, Dmitry (Toronto - BCE); 'yakout yakout'; Colin Barber
> > Cc: ccielab@groupstudy.com
> > Subject: RE: Are EIGRP external routes preferable than OSPF ext ??
> >
> >
> > just curious. Which router is 172.16.222.1. and where do
> > > 172.16.100.0 172.16.5.2 119 0x80000001 0xCB2D 0
> > > 172.16.111.0 172.16.5.2 119 0x80000001 0x529B 0
> > > 172.16.222.0 172.16.5.2 120 0x80000001 0x88F5 0
> > come from?
> >
> > You must have another router hanging in OSPF.
> >
> > --- "Volkov, Dmitry (Toronto - BCE)" <dmitry_volkov@ca.ml.com>
> wrote:
> > > Hi all,
> > >
> > > Tried to put the same config again.
> > > At the beginning I got the same as Yakout, but after clear ip ro
> *
> > on
> > > R11
> > > I got D EX routes.
> > >
> > > Colin is right.
> > > If we change eigrp internal distance on R11 higher than 110
> > > everything seems
> > > to be OK on R11
> > > Yakout, there is nothing wrong with OSPF adjacencies betw R10 &
> > R11.
> > > I have 12.1(16) on R9 and R11 and 12.0(23) on R10
> > >
> > > And again If I remove OSPF from E0/0 on R10 (172.16.1.2 faced to
> > R9)
> > > -
> > > Everything is OK on R11 (only O E2) Why ??
> > >
> > > r11#sh ip ospf nei
> > >
> > > Neighbor ID Pri State Dead Time Address
> > > Interface
> > > 172.16.5.2 1 FULL/BDR 00:00:31 172.16.5.2
> > > Ethernet0
> > > r11#sh ip ospf data
> > >
> > > OSPF Router with ID (172.16.222.1) (Process ID 10)
> > >
> > >
> > > Router Link States (Area 0)
> > >
> > > Link ID ADV Router Age Seq# Checksum
> > Link
> > > count
> > > 172.16.5.2 172.16.5.2 138 0x80000002 0xBD83 2
> > > 172.16.222.1 172.16.222.1 137 0x80000004 0xE269 4
> > >
> > > Net Link States (Area 0)
> > >
> > > Link ID ADV Router Age Seq# Checksum
> > > 172.16.5.1 172.16.222.1 137 0x80000001 0xCAAF
> > >
> > > Type-5 AS External Link States
> > >
> > > Link ID ADV Router Age Seq# Checksum
> Tag
> > > 172.16.1.0 172.16.5.2 146 0x80000001 0x9589 0
> > > 172.16.2.0 172.16.5.2 143 0x80000001 0xD18D 0
> > > 172.16.3.0 172.16.5.2 143 0x80000001 0xC697 0
> > > 172.16.4.0 172.16.5.2 143 0x80000001 0xBBA1 0
> > > 172.16.5.0 172.16.5.2 146 0x80000001 0x69B1 0
>
=== message truncated ===
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