This topic is to discuss the following lesson:
thanks a lot for your helpful explanation, I simulated your lab and found something that I need your explanation for it.
when I leaked 220.127.116.11 at R4, R2 calculated the metric of 18.104.22.168 with 168 as below:
R2#sh ip route isis 1 22.214.171.124/32 is subnetted, 1 subnets i ia 126.96.36.199 [115/168] via 192.168.24.4, 00:14:47, Ethernet0/2
although R4 calculated it with 30 :
R4#sh ip route isis 188.8.131.52/32 is subnetted, 1 subnets i L2 184.108.40.206 [115/30] via 192.168.47.7, 00:50:55, Ethernet0/1
the metric calculated with 40 at R2 when I configured the metric-style wide on all routers, I need your explanation for this please.
That’s a good question. I just booted this topology again and I see a metric of 40 on R2:
R2#show ip route isis Gateway of last resort is 192.168.24.4 to network 0.0.0.0 i*L1 0.0.0.0/0 [115/10] via 192.168.24.4, 00:14:23, GigabitEthernet0/2 220.127.116.11/32 is subnetted, 1 subnets i ia 18.104.22.168 [115/40] via 192.168.24.4, 00:14:23, GigabitEthernet0/2 i L1 192.168.13.0/24 [115/20] via 192.168.12.1, 00:15:16, GigabitEthernet0/1 i L1 192.168.35.0/24 [115/30] via 192.168.12.1, 00:15:10, GigabitEthernet0/1 i L1 192.168.47.0/24 [115/20] via 192.168.24.4, 00:15:16, GigabitEthernet0/2
That’s without wide metrics:
router isis net 49.1234.0000.0000.0002.00 is-type level-1 log-adjacency-changes
router isis net 49.1234.0000.0000.0004.00 log-adjacency-changes redistribute isis ip level-2 into level-1 route-map ROUTE_LEAKING
What do you see in the database?
R2#show isis database level-1 R4.00-00 detail IS-IS Level-1 LSP R4.00-00 LSPID LSP Seq Num LSP Checksum LSP Holdtime/Rcvd ATT/P/OL R4.00-00 0x00000005 0xC9D0 976/1199 1/0/0 Area Address: 49.1234 NLPID: 0xCC Hostname: R4 Metric: 10 IS R4.01 IP Address: 192.168.47.4 Metric: 10 IP 192.168.24.0 255.255.255.0 Metric: 10 IP 192.168.47.0 255.255.255.0 Metric: 30 IP-Interarea 22.214.171.124 255.255.255.255
this command result:
R1 uses R3
Why do you write:
R1 uses R2
why we will configure on R4 , not on R2 , is there a reason or first level-1-2 router
Thanks, this is a typo yes. Just fixed it.
We leak from level 2 into level 1 so that’s why you have to do it on a level 1-2 router (R4 in this case).
When do we use route map and distribute list ?? What are the peculiarities of both?? Can you please distinguish between access list and prefix list also??
Specifically for IS-IS route leaking, you can use either a distribute list or a route-map. Of course, each one has different capabilities. This distinction is not specific to IS-IS route leaking, but is the case for most applications in which both can be used. In general, a distribute list is a more quick and dirty, more simplistic way of implementing route leaking and other similar operations. A route map will provide you with more flexibility and capabilities in matching and taking action. Both can be equally effective for IS-IS route leaking however.
As for access lists and prefix lists, the following lesson explains the difference between the two quite eloquently and should cover most if not all of your questions.
I hope this has been helpful!
Just to be picky: at the beginning there is a “We can deal with this by” that repeats.
Thank you for all these lessons, they are really great!
Thanks for picking this up. You’re not being picky at all, we appreciate you bringing these things to our attention!