- Configuring OSPF TTL Security Check and OSPF Graceful Shutdown
- Enabling OSPFv2 on an Interface Basis
- Configuring NSSA for OSPFv2
- Configuring NSSA for OSPFv3
- IPv6 Routing: OSPFv3 Authentication Support with IPsec
- OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3
- OSPF SNMP ifIndex Value for Interface ID in Data Fields
- OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements
- OSPF Nonstop Routing
- OSPFv2 Local RIB
- IPv6 Routing: OSPFv3
- OSPFv3 Demand Circuit Ignore
- OSPFv3 Max-Metric Router LSA
- OSPFv3 MIB
- OSPFv3 VRF-Lite/PE-CE
- OSPFv3 Authentication Trailer
- OSPF ABR Type 3 LSA Filtering
- Graceful Shutdown Support for OSPFv3
Configuring NSSA for OSPFv2
The Not-So-Stubby Area (NSSA) feature for OSPFv2 enhances the Type 7 autonomous-system external routing calculation and translates the Type 7 Link State Advertisement (LSA) into Type 5 LSA. This feature adds support for the OSPF NSSA specification that is defined by RFC 3101, OSPF Not-So-Stubby Area (NSSA) Option . RFC 3101 replaces RFC 1587, OSPF Not-So-Stubby Area (NSSA) Option, and is backward compatible with RFC 1587. For additional information refer to RFC 3101.
- Finding Feature Information
- Information About Configuring NSSA for OSPF
- How to Configure NSSA for OSPF
- Configuration Examples for OSPF
- Additional References for OSPF Not-So-Stubby Areas (NSSA)
- Feature Information for Configuring NSSA
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Information About Configuring NSSA for OSPF
Characteristics of RFC 3101
RFC 3101 describes the following features:
- Provides an option of importing OSPF summary routes into a Not-So-Stubby Area (NSSA) as Type-3 summary-Link State Advertisement (LSA).
- Refines the setting of the forwarding address in Type-7 LSAs .
- Revises the Type-7 external route calculation .
- Strengthens the process of translating Type-7 LSAs into Type-5 LSAs.
- Modifies the process of flushing translated Type-7 LSAs.
- Defines the P-bit (propagate bit) default as clear.
RFC 1587 Compliance
RFC 3101 compliance is automatically enabled on the devices. Use the compatible rfc1587 command in router configuration mode to revert to route selection that is based on RFC 1587. When you configure the device to be compatible with RFC 1587, the device performs the following actions:
ABR as NSSA Link State Advertisement Translator
Use the Not-So-Stubby Area (NSSA) for Open Shortest Path First version 2 (OSPFv2) feature to simplify administration in a network that connects a central site that uses OSPF to a remote site that is using a different routing protocol.
By implementing NSSA, you can extend OSPF to include the remote connection by defining the area between the border device at the corporate site and the remote device as an NSSA.
As with OSPF stub areas, NSSA areas cannot be injected with distributed routes via Type 5 Link State Advertisement (LSA). Route redistribution into an NSSA area is possible only with Type 7 LSA. An NSSA Autonomous System Border Router (ASBR) generates the Type 7 LSA , and an NSSA Area Border Router (ABR) translates the Type 7 LSA into a Type 5 LSA. These LSAs can be flooded throughout the OSPF routing domain. Route summarization and filtering are supported during the translation.
Route summarization is the consolidation of advertised addresses. This feature enables an ABR to advertise a single summary route to other areas. If the network numbers in an area are assigned in a way such that they are contiguous, you can configure the ABR to advertise a summary route that covers all the individual networks within the area that fall into the specified range.
When routes from other protocols are redistributed to OSPF area, each route is advertised individually in an external LSA. However, you can configure the Cisco IOS software to advertise a single route with a specified network address and mask for all the redistributed routes that are covered by a specified network address and mask. Thus, the size of the OSPF link-state database decreases.
RFC 3101 allows you to configure an NSSA ABR device as a forced NSSA LSA translator.
Note | Even a forced translator might not translate all LSAs; translation depends on the content of each LSA. |
The figure below shows a network diagram in which OSPF Area 1 is defined as the stub area. The Enhanced Interior Gateway Routing Protocol (EIGRP) routes are not propagated into the OSPF domain because routing redistribution is not allowed in the stub area. However, once OSPF Area 1 is defined as an NSSA, an NSSA ASBR can include the EIGRP routes to the OSPF NSSA by generating Type 7 LSAs.
The redistributed routes from the RIP device are not allowed into OSPF Area 1 because NSSA is an extension to the stub area. The stub area characteristics still exist, including the exclusion of Type 5 LSAs.
The figure below shows the OSPF stub network with NSSA Area 1. The redistributed routes that Device 4 is propagating from the two RIP networks is translated into Type 7 LSAs by NSSA ASBR Device 3. Device 2, which is configured to be the NSSA ABR, translates the Type 7 LSAs back to Type 5 so that they can be flooded through the rest of the OSPF stub network within OSPF Area 0.
How to Configure NSSA for OSPF
- Configuring an OSPFv2 NSSA Area and Its Parameters
- Configuring an NSSA ABR as a Forced NSSA LSA Translator
- Disabling RFC 3101 Compatibility and Enabling RFC 1587 Compatibility
Configuring an OSPFv2 NSSA Area and Its Parameters
1.
enable
2.
configure
terminal
3.
router
ospf
process-id
4.
redistribute
protocol
[process-id]
{level-1 |
level-1-2 |
level-2}
[autonomous-system-number]
[metric {metric-value |
transparent}]
[metric-type
type-value]
[match {internal |
external
1 |
external
2}] [tag
tag-value]
[route-map
map-tag]
[subnets]
[nssa-only]
5.
network
ip-address
wildcard-mask
area
area-id
6.
area
area-id
nssa
[no-redistribution] [default-information-originate [metric] [metric-type]] [no-summary] [nssa-only]
7.
summary-address
prefix mask
[not-advertise] [tag tag] [nssa-only]
8.
end
DETAILED STEPS
Configuring an NSSA ABR as a Forced NSSA LSA Translator
1.
enable
2.
configure
terminal
3.
router
ospf
process-id
4.
area
area-id
nssa
translate type7
always
5.
area
area-id
nssa
translate type7
suppress-fa
6.
end
DETAILED STEPS
Disabling RFC 3101 Compatibility and Enabling RFC 1587 Compatibility
1.
enable
2.
configure
terminal
3.
router
ospf
process-id
4.
compatible
rfc1587
5.
end
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 |
enable
Example: Device> enable |
Enables privileged EXEC mode. |
Step 2 |
configure
terminal
Example: Device# configure terminal |
Enters global configuration mode. |
Step 3 |
router
ospf
process-id
Example: Device(config)# router ospf 1 |
Enables OSPF routing and enters router configuration mode. |
Step 4 |
compatible
rfc1587
Example: Device(config-router)# compatible rfc1587 |
Enables the device to be RFC 1587 compliant. |
Step 5 |
end
Example: Device(config-router)# end |
Exits router configuration mode and returns to privileged EXEC mode. |
Configuration Examples for OSPF
- Example: Configuring OSPF NSSA
- Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active
- Example: Verifying OSPF NSSA
Example: Configuring OSPF NSSA
In the following example, an Open Shortest Path First (OSPF) stub network is configured to include OSPF Area 0 and OSPF Area 1, using five devices. Device 3 is configured as the NSSA Autonomous System Border Router (ASBR). Device 2 configured to be the NSSA Area Border Router (ABR). OSPF Area 1 is defined as a Not-So-Stubby Area (NSSA).
Device 1
hostname Device1 ! interface Loopback1 ip address 10.1.0.1 255.255.255.255 ! interface Ethernet0/0 ip address 192.168.0.1 255.255.255.0 ip ospf 1 area 0 no cdp enable ! interface Serial10/0 description Device2 interface s11/0 ip address 192.168.10.1 255.255.255.0 ip ospf 1 area 1 serial restart-delay 0 no cdp enable ! router ospf 1 area 1 nssa ! end
Device 2
hostname Device2 ! ! interface Loopback1 ip address 10.1.0.2 255.255.255.255 ! interface Serial10/0 description Device1 interface s11/0 no ip address shutdown serial restart-delay 0 no cdp enable ! interface Serial11/0 description Device1 interface s10/0 ip address 192.168.10.2 255.255.255.0 ip ospf 1 area 1 serial restart-delay 0 no cdp enable ! interface Serial14/0 description Device3 interface s13/0 ip address 192.168.14.2 255.255.255.0 ip ospf 1 area 1 serial restart-delay 0 no cdp enable ! router ospf 1 area 1 nssa ! end
Device 3
hostname Device3 ! interface Loopback1 ip address 10.1.0.3 255.255.255.255 ! interface Ethernet3/0 ip address 192.168.3.3 255.255.255.0 no cdp enable ! interface Serial13/0 description Device2 interface s14/0 ip address 192.168.14.3 255.255.255.0 ip ospf 1 area 1 serial restart-delay 0 no cdp enable ! router ospf 1 log-adjacency-changes area 1 nssa redistribute rip subnets ! router rip version 2 redistribute ospf 1 metric 15 network 192.168.3.0 end
Device 4
hostname Device4 ! interface Loopback1 ip address 10.1.0.4 255.255.255.255 ! interface Ethernet3/0 ip address 192.168.3.4 255.255.255.0 no cdp enable ! interface Ethernet4/1 ip address 192.168.41.4 255.255.255.0 ! router rip version 2 network 192.168.3.0 network 192.168.41.0 ! end
Device 5
hostname Device5 ! interface Loopback1 ip address 10.1.0.5 255.255.255.255 ! interface Ethernet0/0 ip address 192.168.0.10 255.255.255.0 ip ospf 1 area 0 no cdp enable ! interface Ethernet1/1 ip address 192.168.11.10 255.255.255.0 ip ospf 1 area 0 ! router ospf 1 ! end
Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active
In the following example, the output for the show ip ospf and show ip ospf database nssa commands shows an Open Shortest Path First Not-So-Stubby Area (OSPF NSSA) area where RFC 3101 is disabled, RFC 1587 is active, and an NSSA Area Border Router (ABR) device is configured as a forced NSSA LSA translator. If RFC 3101 is disabled, the forced NSSA LSA translator remains inactive.
Device# show ip ospf Routing Process "ospf 1" with ID 10.0.2.1 Start time: 00:00:25.512, Time elapsed: 00:01:02.200 Supports only single TOS(TOS0) routes Supports opaque LSA Supports Link-local Signaling (LLS) Supports area transit capability Supports NSSA (compatible with RFC 1587) Event-log enabled, Maximum number of events: 1000, Mode: cyclic Router is not originating router-LSAs with maximum metric Initial SPF schedule delay 5000 msecs Minimum hold time between two consecutive SPFs 10000 msecs Maximum wait time between two consecutive SPFs 10000 msecs Incremental-SPF disabled Minimum LSA interval 5 secs Minimum LSA arrival 1000 msecs LSA group pacing timer 240 secs Interface flood pacing timer 33 msecs Retransmission pacing timer 66 msecs Number of external LSA 0. Checksum Sum 0x000000 Number of opaque AS LSA 0. Checksum Sum 0x000000 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 0 normal 0 stub 1 nssa Number of areas transit capable is 0 External flood list length 0 IETF NSF helper support enabled Cisco NSF helper support enabled Reference bandwidth unit is 100 mbps Area 1 Number of interfaces in this area is 1 It is a NSSA area Configured to translate Type-7 LSAs, inactive (RFC3101 support disabled) Area has no authentication SPF algorithm last executed 00:00:07.160 ago SPF algorithm executed 3 times Area ranges are Number of LSA 3. Checksum Sum 0x0245F0 Number of opaque link LSA 0. Checksum Sum 0x000000 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0
The table below describes the show ip ospf display fields and their descriptions.
Field |
Description |
---|---|
Supports NSSA (compatible with RFC 1587) |
Specifies that RFC 1587 is active or that the OSPF NSSA area is RFC 1587 compatible. |
Configured to translate Type-7 LSAs, inactive (RFC3101 support disabled) |
Specifies that OSPF NSSA area has an ABR device configured to act as a forced translator of Type 7 LSAs. However, it is inactive because RFC 3101 is disabled |
Device2# show ip ospf database nssa Router Link States (Area 1) LS age: 28 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.0.2.1 Advertising Router: 10.0.2.1 LS Seq Number: 80000004 Checksum: 0x5CA2 Length: 36 Area Border Router AS Boundary Router Unconditional NSSA translator Number of Links: 1 Link connected to: a Stub Network (Link ID) Network/subnet number: 192.0.2.5 (Link Data) Network Mask: 255.255.255.0 Number of MTID metrics: 0 TOS 0 Metrics: 10
The table below describes the show ip ospf database nssa display fields and their descriptions.
Field |
Description |
---|---|
Unconditional NSSA translator |
Specifies that NSSA ASBR device is a forced NSSA LSA translator |
Example: Verifying OSPF NSSA
The following is sample output from the show ip ospf command. The output displays that OSPF Area 1 is an NSSA area.
Device2# show ip ospf Routing Process "ospf 1" with ID 10.1.0.2 Start time: 00:00:01.392, Time elapsed: 12:03:09.480 Supports only single TOS(TOS0) routes Supports opaque LSA Supports Link-local Signaling (LLS) Supports area transit capability Router is not originating router-LSAs with maximum metric Initial SPF schedule delay 5000 msecs Minimum hold time between two consecutive SPFs 10000 msecs Maximum wait time between two consecutive SPFs 10000 msecs Incremental-SPF disabled Minimum LSA interval 5 secs Minimum LSA arrival 1000 msecs LSA group pacing timer 240 secs Interface flood pacing timer 33 msecs Retransmission pacing timer 66 msecs Number of external LSA 0. Checksum Sum 0x000000 Number of opaque AS LSA 0. Checksum Sum 0x000000 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 0 normal 0 stub 1 nssa Number of areas transit capable is 0 External flood list length 0 Area 1 Number of interfaces in this area is 2 ! It is a NSSA area Area has no authentication SPF algorithm last executed 11:37:58.836 ago SPF algorithm executed 3 times Area ranges are Number of LSA 7. Checksum Sum 0x045598 Number of opaque link LSA 0. Checksum Sum 0x000000 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 Device2# show ip ospf data OSPF Router with ID (10.1.0.2) (Process ID 1) Router Link States (Area 1) Link ID ADV Router Age Seq# Checksum Link count 10.1.0.1 10.1.0.1 1990 0x80000016 0x00CBCB 2 10.1.0.2 10.1.0.2 1753 0x80000016 0x009371 4 10.1.0.3 10.1.0.3 1903 0x80000016 0x004149 2 Summary Net Link States (Area 1) Link ID ADV Router Age Seq# Checksum 192.168.0.0 10.1.0.1 1990 0x80000017 0x00A605 192.168.11.0 10.1.0.1 1990 0x80000015 0x009503 Type-7 AS External Link States (Area 1) Link ID ADV Router Age Seq# Checksum Tag 192.168.3.0 10.1.0.3 1903 0x80000015 0x00484F 0 192.168.41.0 10.1.0.3 1903 0x80000015 0x00A4CC 0
The following is sample output from the show ip ospf database data command. The output displays additional information about redistribution between Type 5 and Type 7 LSAs for routes that are injected into the NSSA area and then flooded through the OSPF network.
Device2# show ip ospf database data OSPF Router with ID (10.1.0.2) (Process ID 1) Area 1 database summary LSA Type Count Delete Maxage Router 3 0 0 Network 0 0 0 Summary Net 2 0 0 Summary ASBR 0 0 0 Type-7 Ext 2 0 0 Prefixes redistributed in Type-7 0 Opaque Link 0 0 0 Opaque Area 0 0 0 Subtotal 7 0 0 Process 1 database summary LSA Type Count Delete Maxage Router 3 0 0 Network 0 0 0 Summary Net 2 0 0 Summary ASBR 0 0 0 Type-7 Ext 2 0 0 Opaque Link 0 0 0 Opaque Area 0 0 0 Type-5 Ext 0 0 0 Prefixes redistributed in Type-5 0 Opaque AS 0 0 0 Total 7 0 0
The following is sample output from the show ip ospf database nssa command. The output displays detailed information for Type 7 to Type 5 translations:
Device2# show ip ospf database nssa OSPF Router with ID (10.1.0.2) (Process ID 1) Type-7 AS External Link States (Area 1) Routing Bit Set on this LSA LS age: 1903 Options: (No TOS-capability, Type 7/5 translation, DC) LS Type: AS External Link Link State ID: 192.168.3.0 (External Network Number ) Advertising Router: 10.1.0.3 LS Seq Number: 80000015 Checksum: 0x484F Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 192.168.14.3 External Route Tag: 0 Routing Bit Set on this LSA LS age: 1903 ! Options: (No TOS-capability, Type 7/5 translation, DC) LS Type: AS External Link Link State ID: 192.168.41.0 (External Network Number ) Advertising Router: 10.1.0.3 LS Seq Number: 80000015 Checksum: 0xA4CC Length: 36 Network Mask: /24 Metric Type: 2 (Larger than any link state path) TOS: 0 Metric: 20 Forward Address: 192.168.14.3 External Route Tag: 0
Example: OSPF NSSA Area with RFC 3101 Disabled and RFC 1587 Active
The following sample output from the show ip ospf command displays that the device is acting as an ASBR and OSPF Area 1 is configured as an NSSA area:
Device3# show ip ospf Routing Process "ospf 1" with ID 10.1.0.3 Start time: 00:00:01.392, Time elapsed: 12:02:34.572 Supports only single TOS(TOS0) routes Supports opaque LSA Supports Link-local Signaling (LLS) Supports area transit capability !It is an autonomous system boundary router Redistributing External Routes from, rip, includes subnets in redistribution Router is not originating router-LSAs with maximum metric Initial SPF schedule delay 5000 msecs Minimum hold time between two consecutive SPFs 10000 msecs Maximum wait time between two consecutive SPFs 10000 msecs Incremental-SPF disabled Minimum LSA interval 5 secs Minimum LSA arrival 1000 msecs LSA group pacing timer 240 secs Interface flood pacing timer 33 msecs Retransmission pacing timer 66 msecs Number of external LSA 0. Checksum Sum 0x000000 Number of opaque AS LSA 0. Checksum Sum 0x000000 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 0 normal 0 stub 1 nssa Number of areas transit capable is 0 External flood list length 0 Area 1 Number of interfaces in this area is 1 ! It is a NSSA area Area has no authentication SPF algorithm last executed 11:38:13.368 ago SPF algorithm executed 3 times Area ranges are Number of LSA 7. Checksum Sum 0x050CF7 Number of opaque link LSA 0. Checksum Sum 0x000000 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0
The table below describes the significant fields shown in the show ip ospf command output.
Field |
Description |
---|---|
Routing process "ospf 1" with ID 10.1.0.3 |
Process ID and OSPF router ID. |
Supports ... |
Number of types of service supported (Type 0 only). |
Summary Link update interval |
Specifies summary update interval in hours:minutes:seconds, and time until next update. |
External Link update interval |
Specifies external update interval in hours:minutes:seconds, and time until next update. |
Redistributing External Routes from |
Lists of redistributed routes, by protocol. |
SPF calculations |
Lists start, hold, and maximum wait interval values in milliseconds. |
Number of areas |
Number of areas in router, area addresses, and so on. |
SPF algorithm last executed |
Shows the last time an SPF calculation was performed in response to topology change event records. |
Link State Update Interval |
Specifies router and network link-state update interval in hours:minutes:seconds, and time until next update. |
Link State Age Interval |
Specifies max-aged update deletion interval, and time until next database cleanup, in hours:minutes:seconds. |
In the following example, the output for the show ip ospf and show ip ospf database nssa commands shows an Open Shortest Path First Not-So-Stubby Area (OSPF NSSA) area where RFC 3101 is disabled, RFC 1587 is active, and an NSSA Area Border Router (ABR) device is configured as a forced NSSA LSA translator. If RFC 3101 is disabled, the forced NSSA LSA translator remains inactive.
Device# show ip ospf Routing Process "ospf 1" with ID 10.0.2.1 Start time: 00:00:25.512, Time elapsed: 00:01:02.200 Supports only single TOS(TOS0) routes Supports opaque LSA Supports Link-local Signaling (LLS) Supports area transit capability Supports NSSA (compatible with RFC 1587) Event-log enabled, Maximum number of events: 1000, Mode: cyclic Router is not originating router-LSAs with maximum metric Initial SPF schedule delay 5000 msecs Minimum hold time between two consecutive SPFs 10000 msecs Maximum wait time between two consecutive SPFs 10000 msecs Incremental-SPF disabled Minimum LSA interval 5 secs Minimum LSA arrival 1000 msecs LSA group pacing timer 240 secs Interface flood pacing timer 33 msecs Retransmission pacing timer 66 msecs Number of external LSA 0. Checksum Sum 0x000000 Number of opaque AS LSA 0. Checksum Sum 0x000000 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 0 normal 0 stub 1 nssa Number of areas transit capable is 0 External flood list length 0 IETF NSF helper support enabled Cisco NSF helper support enabled Reference bandwidth unit is 100 mbps Area 1 Number of interfaces in this area is 1 It is a NSSA area Configured to translate Type-7 LSAs, inactive (RFC3101 support disabled) Area has no authentication SPF algorithm last executed 00:00:07.160 ago SPF algorithm executed 3 times Area ranges are Number of LSA 3. Checksum Sum 0x0245F0 Number of opaque link LSA 0. Checksum Sum 0x000000 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0
The table below describes the significant fields shown in the show ip ospf command output.
Field |
Description |
---|---|
Supports NSSA (compatible with RFC 1587) |
Specifies that RFC 1587 is active or that the OSPF NSSA area is RFC 1587 compatible. |
Configured to translate Type-7 LSAs, inactive (RFC3101 support disabled) |
Specifies that OSPF NSSA area has an ABR device configured to act as a forced translator of Type 7 LSAs. However, it is inactive because RFC 3101 is disabled |
Device2# show ip ospf database nssa Router Link States (Area 1) LS age: 28 Options: (No TOS-capability, DC) LS Type: Router Links Link State ID: 10.0.2.1 Advertising Router: 10.0.2.1 LS Seq Number: 80000004 Checksum: 0x5CA2 Length: 36 Area Border Router AS Boundary Router Unconditional NSSA translator Number of Links: 1 Link connected to: a Stub Network (Link ID) Network/subnet number: 192.0.2.5 (Link Data) Network Mask: 255.255.255.0 Number of MTID metrics: 0 TOS 0 Metrics: 10
The table below describes the significant fields shown in the show ip ospf database nssa command output.
Field |
Description |
---|---|
Unconditional NSSA translator |
Specifies that NSSA ASBR device is a forced NSSA LSA translator |
Additional References for OSPF Not-So-Stubby Areas (NSSA)
Related Documents
Related Topic |
Document Title |
---|---|
Cisco IOS commands |
|
OSPF commands |
|
Protocol-independent features that work with OSPF |
“Configuring IP Routing Protocol-Independent Features” module in IP Routing: Protocol-Independent Configuration Guide |
RFCs
RFC |
Title |
---|---|
RFC 1587 |
The OSPF NSSA Option, March 1994 |
RFC 3101 |
The OSPF NSSA Option January 2003 |
Technical Assistance
Description |
Link |
---|---|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for Configuring NSSA
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
---|---|---|
OSPF Support for NSSA RFC 3101 |
15.2(1)E |
The OSPF Not-So-Stubby Areas (NSSA) feature enhances the Type 7 autonomous-system external routing calculation and translates the Type 7 Link State Advertisement (LSA) into Type 5 LSA. This feature adds support for the OSPF NSSA specification defined by RFC 3101 (OSPF Not-So-Stubby Area (NSSA) Option). In Cisco IOS 15.2(1)E, support was added for the Cisco Catalyst 4000 Series Switches. The following commands were introduced or modified: area nssa translate, compatible rfc1587. |