topic Re: VOSS OSPF Totally NSSA in ExtremeSwitching (VSP/Fabric Engine)

VOSS OSPF Totally NSSA

Fijs — Thu, 02 Jul 2020 19:28:18 GMT

Hi,

Does VOSS support totally NSSA’s?

I have managed to configure stub area’s, totally stubby area’s, but I don’t see any option to create a totally nssa.

What I want to achieve: having totally stubby area (only a default route towards area 0), but other routers in that area should be able to redistribute static routes back into area 0.

Thanks!

Re: VOSS OSPF Totally NSSA

EXTR_Paul — Mon, 06 Jul 2020 20:28:48 GMT

page 45, 97, and in a several other parts of this doc are config and variable examples.

https://documentation.extremenetworks.com/VOSS/SW/81x/ConfigOSPFRIPVOSS_8.1.5_CG.pdf?_ga=2.266960910.1421259737.1594041938-1780913995.1569634769

Re: VOSS OSPF Totally NSSA

Fijs — Mon, 06 Jul 2020 22:20:53 GMT

Hi Paul,

Thanks for the link. I ideed used this guide to successfully configure stub, totally stub, and nssa areas.

However it does not cover “totally nssa” / “NSSA Totally Stub Area”.

A “totally nssa” area should advertise only a default route from the ABR. The difference with a “totally stubby area”, is that a “totally nssa” can have ASBR’s in it.

So I guess I should configure the area as NSSA, and set “no area X.X.X.X import-summaries enable”; but this is not possible:

VSP:1(config-ospf)#area 1.0.0.0 import nssa
VSP:1(config-ospf)#no area 1.0.0.0 import-summaries enable
Error: cannot set import summary to be false if not stub area

Also,

area X.X.X.X stub

and

are X.X.X.X import nssa

seems to be mutually exclusive:

### NSSA ###
VSP:1(config-ospf)#area 1.0.0.0 import nssa
VSP:1(config-ospf)#sho ip ospf area


====================================================================================================
                            OSPF Area - GlobalRouter
====================================================================================================
AREA_ID         STUB_AREA  NSSA          IMPORT_SUM ACTIVE_IFCNT
----------------------------------------------------------------------------------------------------
0.0.0.0         false      false         true       0
1.0.0.0         false      true          true       0

STUB_COST INTRA_AREA_SPF_RUNS  BDR_RTR_CNT ASBDR_RTR_CNT LSA_CNT   LSACK_SUM
----------------------------------------------------------------------------------------------------
0         0                    0           0             0         0
1         0                    0           0             0         0

### Changing to Stub ###
VSP:1(config-ospf)#area 1.0.0.0 stub
VSP:1(config-ospf)#sho ip ospf area


====================================================================================================
                            OSPF Area - GlobalRouter
====================================================================================================
AREA_ID         STUB_AREA  NSSA          IMPORT_SUM ACTIVE_IFCNT
----------------------------------------------------------------------------------------------------
0.0.0.0         false      false         true       0
1.0.0.0         true       false         true       0

STUB_COST INTRA_AREA_SPF_RUNS  BDR_RTR_CNT ASBDR_RTR_CNT LSA_CNT   LSACK_SUM
----------------------------------------------------------------------------------------------------
0         0                    0           0             0         0
1         0                    0           0             0         0

Re: VOSS OSPF Totally NSSA

RobertD1 — Tue, 21 Jun 2022 12:17:04 GMT

Hi,

How do you disable Import-Summaries for NSSA, it seems can only be done for area stub?

It does appear not to send other LSA types 5, 4 and 3 into the area, only a default route is seen via NSSA LSA (and any local routes of course).

It is just not clear then what the difference is between NSSA and Totally NSSA I suppose. No default-information-originate option.

If all routers in NSSA need to be configured as NSSA how does it know which one to originate the default route from?

Rob