This topic is to discuss the following lesson:
1 Like
Hi Rene,
Is there any rule to connected other Routing protocol or we can do redistribution any where suppose L1/L2 or L1-L2 Router?? Thanks
br//zaman
Hi Zaman,
Not really, when you redistribute something into IS-IS you can do it on any router and redistribute into L1, L2 or both L1 and L2.
Rene
Hi Rene,
I have set up a LAB with multiple ISIS Instance/TAG . Then Redistribute those Instances with each other using Route-Map matching Loopback IP’s and TAG value. But I am not getting 2.2.2.2/32 prefix from R1 and 4.4.4.4/32, 44.44.44.44/32 prefix from R3 whether I configured Instance Redistribution on R2 and R4 .Please check the topology & Configuration attached.ISIS config !!.txt (3.5 KB)
BR//ZAMAN
Hello Zaman,
If you lab up something like this, first try the basic redistribution commands without route-maps or tags (maybe you did).
I labbed up redistribution between IS-IS processes on IOSv (Cisco VIRL) but whatever I tried, it was impossible to redistribute routes from one process into another. Maybe it’s related to Cisco IOS or the version that I used. The commands are accepted but it doesn’t redistribute anything.
On IOS XR, it works. Here’s a working configuration for three routers connected like this:
R1-R2-R3
hostname R1
!
interface GigabitEthernet0/0/0/0
ipv4 address 192.168.12.1 255.255.255.0
!
router isis AREA12
is-type level-2-only
net 49.0012.0000.0000.0001.00
log adjacency changes
interface GigabitEthernet0/0/0/0
address-family ipv4 unicast
!
endhostname R2
!
interface GigabitEthernet0/0/0/0
ipv4 address 192.168.12.2 255.255.255.0
!
interface GigabitEthernet0/0/0/1
ipv4 address 192.168.23.2 255.255.255.0
!
router isis AREA12
is-type level-2-only
net 49.0012.0000.0000.0002.00
log adjacency changes
address-family ipv4 unicast
redistribute isis AREA23 metric 10
!
interface GigabitEthernet0/0/0/0
address-family ipv4 unicast
!
router isis AREA23
is-type level-2-only
net 49.0023.0000.0000.0002.00
log adjacency changes
interface GigabitEthernet0/0/0/1
address-family ipv4 unicast
!
endhostname R3
interface Loopback0
ipv4 address 3.3.3.3 255.255.255.255
!
interface GigabitEthernet0/0/0/0
ipv4 address 192.168.23.3 255.255.255.0
!
router isis AREA23
is-type level-2-only
net 49.0023.0000.0000.003.00
log adjacency changes
interface Loopback0
address-family ipv4 unicast
!
interface GigabitEthernet0/0/0/0
address-family ipv4 unicast
!
end
This redistributes the 3.3.3.3/32 and 192.168.23.0/24 prefixes from one process into another on R2.
RP/0/0/CPU0:R1#show ip route isis
Fri Mar 1 09:22:17.082 UTC
i L2 3.3.3.3/32 [115/20] via 192.168.12.2, 00:04:41, GigabitEthernet0/0/0/0
i L2 192.168.23.0/24 [115/20] via 192.168.12.2, 00:04:41, GigabitEthernet0/0/0/0Hope this helps. You can add the route-maps / tags to this if needed.
Rene
Hi,
Thanks Rene for your valuable input . In My LAB Only local connected (Loopback) prefix will not distributed But others prefix distributed fine . In R2 , when redistributed (24 to AREA12) to AREA12 , only 2.2.2.2/32 prefix not come to AREA12 but all others prefix (3.3.3.3/32 ; 4.4.4.4/32) redistributed fine . See the output below :
R1#show ip route
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback0
3.0.0.0/32 is subnetted, 1 subnets
**i L2 3.3.3.3 [115/30] via 192.168.12.2, 00:00:48, FastEthernet0/0**
4.0.0.0/32 is subnetted, 1 subnets
**i L2 4.4.4.4 [115/30] via 192.168.12.2, 00:00:48, FastEthernet0/0**
192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.12.0/24 is directly connected, FastEthernet0/0
L 192.168.12.1/32 is directly connected, FastEthernet0/0
Only 2.2.2.2/32 not coming .
As per your observation Multi process ISIS , redistribution with Route-map between Process will works fine , right ??
One More query , A process must have One NET address and NET address should be Unique . Here In your configuration on R2 you used net 49.0012.0000.0000.0002.00 & net 49.0023.0000.0000.0002.00 for two process (24 & area23) but In both the sysID (0000.0000.0002) is same . When I tried to configure like this I am getting a error and can’t configure …
%CLNS: Duplicate system ID configured in ip vrf with router isis 24
Please help to know about the issue .Thanks
BR//ZAMAN
Hi Zaman,
That’s interesting. What IOS version did you use? Whatever I did on IOS 15 in VIRL, I couldn’t get anything distributed 
If you remove the route-maps and redistribute everything, does your 2.2.2.2/32 prefix show up? Is 2.2.2.2/32 in the IS-IS database on R2?
I had the same error on IOS but on IOS XR this is accepted. It seems the implementation of IS-IS on IOS and IOS XR is slightly different.
Hello Rene,
VIRL used to be Cisco CML right? Since I’m using it right now as well and nothing gets redistributed. The only node where redistribution works is IOS-XR.
David
Hello David
Virtual Internet Routing Labs (VIRL) was the previous version of CML before it got rebranded. In 2020, VIRL 2.0 was rebranded as CML-Personal (CML-P). Since then it has been produced and advanced as CML. It seems that the behavior in VIRL that Rene mentions is still valid in today’s CML, thanks for confirming this David.
There is some evidence of such limitations of IOSv images in CML which are documented in Cisco community forums, so if you’re using IS-IS, it’s best to stick with IOS-XR or try CSR1000v nodes if available in your CML deployment.
I hope this has been helpful!
Laz
Hello Laz.
I’ve tried both CSR and CATV IOS-XE nodes. The problem is the following:
- If you do not specify anything in the redistribution command, the default settings make the route appear as external and as a L2 route.
Since my routers had only a L1 adjacency, they would never advertise this route to eachother.. the funny thing is, you cannot change the level when redistributing in CML on IOS and IOS-XE nodes, this is probably a bug.
Since this works just fine in an IS-IS book that I am reading
RT1#show running-config
[snip]
router isis
redistribute static ip metric 0 metric-type internal level-2
net 49.0001.0000.0000.0001.00
!
ip route 172.16.1.0 255.255.255.0 Null0
[snip]
David