From: Eli Kosharovsky (eli_kosh@netvision.net.il)
Date: Mon Jan 29 2007 - 09:18:46 ART
Thanks alot,
This makes things much more clearer.
Eli
_____
From: ccie anees [mailto:ccieanees@yahoo.com]
Sent: Monday, January 29, 2007 2:17 AM
To: Eli Kosharovsky; ccielab@groupstudy.com
Subject: Re: OSPF - translate type7 suppress-fa
I have posted a mail on this before. I am just pasting it here:
Please take some time and look at this config
area 1 (NSSA) Area 0
R1 --------------------- R2 ------------------- R3
X.X.12.0/30 X.X.23.0/30
Step1:
######
R1:
redistribute Loopback0 (1.1.1.1)
Verify Result
##############
in R3:
show ip route will show
1.1.1.0/24 as E2 route.
X.X.12.0/30 as O IA route
************************************************************
Step2:
######
Suppress Area 1 route X.X.12.0/24 in Area 0
###########################################
R2:
router ospf 1
area 1 range X.X.12.0 255.255.255.0 no-advertise
Verify in R3:
show ip route
you will not see both the routes X.X.12.0/30 and 1.1.1.0/24
R3#show ip ospf database external
OSPF Router with ID (3.3.3.3) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 168
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 1.1.1.0 (External Network Number )
Advertising Router: 1.1.1.1
LS Seq Number: 80000001
Checksum: 0x38F0
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 1.1.12.1 <-----------------------------
External Route Tag: 0
Note:
you can see above that the forwarding address 1.1.12.1 for the
redistributed
route 1.1.1.0.
And we filtered the X.X.12.0 from ABR (R2).
Because R3 does not have route to reach X.X.12.1, it can not populate
1.1.1.1
in R3 Routing table.
****************************************************************************
******
Step3:
######
NSSA forwarding address suppression
###################################
R2:
router ospf 1
area 1 nssa translate type7 suppress-fa
Verify in R3
R3#show ip ospf database external
OSPF Router with ID (3.3.3.3) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 6
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 1.1.1.0 (External Network Number )
Advertising Router: 1.1.1.1
LS Seq Number: 80000002
Checksum: 0x61D6
Length: 36
Network Mask: /24
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0 <-----------------------------
External Route Tag: 0
Note: Now the forwarding address is 0.0.0.0 which is nothing but the
border-router. Now the router knows how to reach the border-router
which is X.X.23.2, it populates 1.1.1.0/24 in the routing table.
R3#show ip ospf border-routers
OSPF Process 1 internal Routing Table
Codes: i - Intra-area route, I - Inter-area route
i 2.2.2.2 [647] via 1.1.23.2, Serial1/2, ABR/ASBR, Area 3, SPF 117
############################################################################
END
###########################################################################
Eli Kosharovsky <eli_kosh@netvision.net.il> wrote:
Hi GS,
I am trying to understand what the OSPF command:
Area 1 nssa translate type7 suppress-fa
As far as I know nssa allows for translation of type 7 to type 5 LSA's and
this is achieved just by defining the OSPF area as an "nssa". While doing a
mock lab a requirement was made to suppress the original (type 7) advertiser
address. I have checked a backbone router which is not an ABR for the NSSA
to see who is the advertising router of the translated type 7 routes (the
type 5 ) - the adv ID was that of the NSSA ABR. I have added and removed
the command "Area 1 nssa translate type7 suppress-fa" sevral times. While I
saw the Seq number increased in the OSPF database, there was no change in
the LSA data.
From what I can understand this command does nothing.
What does this command do, I have read the DocCD a several time, and I cant
make it out . Please Help
Thanks in advance
Eli
This archive was generated by hypermail 2.1.4 : Thu Feb 08 2007 - 23:46:57 ART