IS-IS Multi-level1 areas on a single router issues.

Hello, I have just started learning IS-IS and poking around. I ran into some problems with recent Cisco IOS versions that I haven't had on 12.x IOS.

►First when creating a new IS-IS process :

D(config-if)#router isis

D(config-router)#net 02.0100.0000.0004.00

D(config-router-af)#Router isis areaZero

D(config-router)#net 00.0100.0000.0004.00

%CLNS: Duplicate system ID configured in ip vrf <default> with router isis null

The NET in the new IS-IS process wouldn't be accepted because it had same SysID with the null process.

replaced the router D with an older one who has IOS 12.4, here is the NET configuration :

D#show run | S router

!

router isis

net 02.0100.0000.0004.00

!

router isis areaZero

net 00.0100.0000.0004.00

!

!

Same SysID for both IS-IS instances.

​

►Second the Router that has multi L1 areas wasn't setting the ATT bit for the areas where he wasn't L2.

D#show isis database

Tag null: IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

D.00-00 * 0x0000000E 0xE4BA 1036 1/0/0

Tag areaZero: IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

D.00-00 * 0x00000008 0xFE1A 858 0/0/0

While in 12.4 it sets the ATT bit for every L1 area

D#show isis database level-1

Area null: IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

D.00-00 * 0x00000015 0x51E1 899 1/0/0

Area areaZero: IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

D.00-00 * 0x00000006 0xFA15 899 1/0/0

►And third the routes learned from the secondary level-1 areas are not redistributed into level-2.

this is from the 12.4, where routes are redistributed from other L1s to the main L2 :

D#show isis database detail

Area null:

!

IS-IS Level-2 Link State Database:

!

Metric: 20 IP 192.168.1.0/26

!

Area areaZero: IS-IS Level-1 Link State Database:

LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL

A.00-00 0x0000000E 0x8D61 591 0/0/0

!

Metric: 10 IP 192.168.1.16/28

Metric: 10 IP 192.168.1.48/28

!

B.00-00 0x0000000D 0x43BA 331 0/0/0

!

Metric: 10 IP 192.168.1.32/28

Metric: 10 IP 192.168.1.48/28

!

C.00-00 0x00000017 0x1E92 518 0/0/0

!

Metric: 10 IP 192.168.1.48/28

Metric: 10 IP 192.168.1.132/30

!

!

the subnets from 192.168.1.0/26 which have been learned from areaZero level-1, are redistributed into level-2 of the process null as a summary.

​

Can anyone help me find the documentation about the IS-IS changes in IOS, and how to get it to behave like older versions.