[c-nsp] ISIS Problem
Ibrahim Abo Zaid
ibrahim.abozaid at gmail.com
Tue Aug 18 03:24:02 EDT 2009
Hi All
R1 isn't setting ATT bit in its LSP it is like that R1 forwards L1 default
route to all its L1 neighbors in DEF the originatation area (but it is not
shown in R1-LSP) , I connected R4 to R1 with L2 ADJ between them and there
is no DEF route !!
any explainsion ?
R1#sh isis database
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 * 0x00000003 0xD80B 1161 0/0/0
R2.00-00 0x00000003 0xDE59 1165 1/0/0
R3.00-00 0x00000003 0xDF77 1165 1/0/0
R1#sh isis database R1.00-00 detail
IS-IS Level-1 LSP R1.00-00
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 * 0x00000007 0x2B0C 629 0/0/0
Area Address: 49.0001
NLPID: 0xCC
Hostname: R1
IP Address: 10.10.13.1
Metric: 10 IP 10.10.12.0/24
Metric: 10 IP 10.10.13.0/24
Metric: 10 IS-Extended R3.00
Metric: 10 IS-Extended R2.00
IS-IS Level-2 LSP R1.00-00
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 * 0x00000005 0x6E68 1199 0/0/0
Area Address: 49.0001
NLPID: 0xCC
Hostname: R1
IP Address: 10.10.13.1
Metric: 10 IP 10.14.1.0/24
Metric: 10 IS-Extended R4.01
Metric: 10 IP 10.10.12.2/32
Metric: 10 IP 10.10.12.0/24
Metric: 10 IP 10.10.13.3/32
Metric: 10 IP 10.10.13.0/24
R2#sh isis database
Area 2:
IS-IS Level-2 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R2.00-00 * 0x00000004 0x6D77 1156 0/0/0
R3.00-00 0x00000004 0x934E 1154 0/0/0
Area null:
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 0x00000003 0xD80B 1143 0/0/0
R2.00-00 * 0x00000003 0xDE59 1150 1/0/0
R3.00-00 0x00000003 0xDF77 1147 1/0/0
R3#sh isis database
Area 3:
IS-IS Level-2 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R2.00-00 0x00000004 0x6D77 1137 0/0/0
R3.00-00 * 0x00000004 0x934E 1138 0/0/0
Area null:
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 0x00000003 0xD80B 1125 0/0/0
R2.00-00 0x00000003 0xDE59 1129 1/0/0
R3.00-00 * 0x00000003 0xDF77 1132 1/0/0
On Tue, Aug 18, 2009 at 1:51 AM, BRYAN BARTIK <bbartik at uen.org> wrote:
> Hello,
>
> Do a "show isis database" and you will see who is setting the ATT bit. R2
> and R3 are setting the ATT bits and these get flooded to R1 and then across
> to each other in L1. Probably looks like this:
>
> R1#sho isis database
>
> IS-IS Level-1 Link State Database:
> LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
> R1.00-00 * 0x00000003 0x5524 1173 0/0/0
> R2.00-00 0x00000003 0x7E42 1161 1/0/0
> R3.00-00 0x00000003 0xC8F2 1179 1/0/0
>
> -Bryan
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net [mailto:
> cisco-nsp-bounces at puck.nether.net] On Behalf Of Ibrahim Abo Zaid
> Sent: Monday, August 17, 2009 2:47 PM
> To: cisco_nsp; cisco at groupstudy.com
> Subject: [c-nsp] ISIS Problem
>
> Hi All
>
> I have a problem with the below ISIS toplogy , All ADJ of R1 are L1 and
> interface between R2 is in A2 from R2 side and in A3 side from R3 side
> so R2 and R3 have L2-ADJ betwene them , as expected both R2 and R3 send LSP
> with ATT bit set so R1 has 2 L1 default routes point to both R2 and R3 ,
> the
> wired result there is L1 on both R2 and R3 points to R1 !! but R1 don't set
> ATT bit in its LSP
>
> do you explainsation why R1 sends this default route ? and how we can stop
> it
>
> Topology
>
> R2--------L-1------------
> | |
> | |
> L2 A-1 R1
> | |
> | |
> R3---------L-1-----------
>
> Configuration
>
> R1
>
> !
> interface Serial1/0
> description to R2
> ip address 10.10.12.1 255.255.255.0
> ip router isis
> encapsulation ppp
> !
> interface Serial1/1
> description to R3
> ip address 10.10.13.1 255.255.255.0
> ip router isis
> encapsulation ppp
> !
> router isis
> net 49.0001.0000.0000.0001.00
> is-type level-1
>
>
> R2
>
> interface Serial1/0
> description to R1
> ip address 10.10.12.2 255.255.255.0
> ip router isis
> encapsulation ppp
> !
> interface Serial1/1
> description to R3
> ip address 10.10.23.2 255.255.255.0
> ip router isis 2
> encapsulation ppp
> !
> router isis 2
> net 49.0002.0000.0000.0002.00
> is-type level-2-only
> !
> router isis
> net 49.0001.0000.0000.0002.00
> is-type level-1
>
>
> R3
>
> interface Serial 1/0
> description to R1
> ip address 10.10.13.3 255.255.255.0
> ip router isis
> encapsulation ppp
> !
> interface Serial 1/1
> description to R2
> ip address 10.10.23.3 255.255.255.0
> ip router isis 3
> encapsulation ppp
> !
> router isis 3
> net 49.0003.0000.0000.0003.00
> is-type level-2-only
> !
> router isis
> net 49.0001.0000.0000.0003.00
> is-type level-1
>
>
> Logs
> -------
>
>
> R1#sh clns neighbors
> System Id Interface SNPA State Holdtime Type
> Protocol
> R2 Se1/0 *PPP* Up 22 L1 IS-IS
> R3 Se1/1 *PPP* Up 23 L1 IS-IS
>
>
> R2#sh clns neighbors
> Area 2:
> System Id Interface SNPA State Holdtime Type
> Protocol
> R3 Se1/1 *PPP* Up 28 L2 IS-IS
> Area null:
> System Id Interface SNPA State Holdtime Type
> Protocol
> R1 Se1/0 *PPP* Up 26 L1 IS-IS
>
>
> R3#sh clns neighbors
> Area 3:
> System Id Interface SNPA State Holdtime Type
> Protocol
> R2 Se1/1 *PPP* Up 22 L2 IS-IS
> Area null:
> System Id Interface SNPA State Holdtime Type
> Protocol
> R1 Se1/0 *PPP* Up 28 L1 IS-IS
>
> routing tables
> -----------------
>
> R1#sh ip route isis
> i*L1 0.0.0.0/0 [115/10] via 10.10.13.3, Serial1/1
> [115/10] via 10.10.12.2, Serial1/0
>
> R2#sh ip route isis
> i L2 10.10.13.1/32 [115/20] via 10.10.23.3, Serial1/0
> i L1 10.10.13.0/24 [115/20] via 10.10.12.1, Serial1/0
> i*L1 0.0.0.0/0 [115/20] via 10.10.12.1, Serial1/0
>
>
> R3#sh ip route isis
> i L1 10.10.12.0/24 [115/20] via 10.10.13.1, Serial1/0
> i L2 10.10.12.1/32 [115/20] via 10.10.23.2, Serial1/1
> i*L1 0.0.0.0/0 [115/20] via 10.10.13.1, Serial1/0
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