[c-nsp] ISIS Problem

Ibrahim Abo Zaid ibrahim.abozaid at gmail.com
Tue Aug 18 09:24:47 EDT 2009


Hi all

To make it clearer , i don't have a problem with default route on R1 i have
a problem with the default route on R2 and R3


best regards
--Ibrahim

On Tue, Aug 18, 2009 at 10:24 AM, Ibrahim Abo Zaid <
ibrahim.abozaid at gmail.com> wrote:

>  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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>>
>
>


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