Graceful Restart and Not-So-Stubby Area (NSSA) Supported for Open Shortest Path First (OSPFv3)

This feature upgrades Open Shortest Path First (OSPFv3) to support graceful restart and Not-So-Stubby Area (NSSA):

Graceful OSPFv3 Restart—RFC 5187 describes a way for OSPFv3 control functions to restart without disrupting traffic forwarding. Without graceful restart, adjacent routers assume that information previously received from the restarting router is stale and should not be used to forward traffic to that router. However, in many cases, two conditions exist that allow the router restarting OSPFv3 to continue to forward traffic correctly. The first condition is that forwarding can continue while the control function is restarted. Most modern router system designs separate the forwarding function from the control function so that traffic can still be forwarded independent of the state of the OSPFv3 function. Routes learned through OSPFv3 remain in the routing table and packets continue to be forwarded. The second condition required for graceful restart is that the network remain stable during the restart period. If the network topology is not changing, the current routing table remains correct. Often, networks can remain stable during the time for restarting OSPFv3.
NSSA—NSSA is an extension of OSPFv3 stub area. External routes originating from an Autonomous System Boundary Router (ASBR) connected to an NSSA can be advertised within the area and can be advertised to other areas as autonomous system (AS)-external link-state advertisements (LSAs).

Supported Platforms

Summit X450-G2, X460, X460-G2, X480, X670, X670-G2, and X770 series switches
BlackDiamond X8 and 8000 series switches
E4G-200 and E4G-400 cell site routers

New CLI Commands

configure ospfv3 lsa-batch-interval seconds

configure ospfv3 area area-identifier nssa [nosummary | summary] stub-defaultcost cost {translate}

configure ospfv3 restart [none | planned | unplanned | both]

configure ospfv3 restart grace-period seconds

configure ospfv3 [[vlan | tunnel] all | {vlan} vlan-name | {tunnel} tunnel-name | area area-identifier] restart-helper [none | planned | unplanned | both]

enable ospfv3 [[vlan | tunnel] all | {vlan} vlan-name | {tunnel} tunnel-name | area area-identifier] restart-helper-lsa-check

disable ospfv3 [[vlan | tunnel] all | {vlan} vlan-name | {tunnel} tunnel-name | area area-identifier] restart-helper-lsa-check

enable ospfv3 virtual-link {routerid} router-identifier {area} area-identifier restart-helper-lsa-check

disable ospfv3 virtual-link {routerid} router-identifier {area} area-identifier restart-helper-lsa-check

Changed CLI Commands

Changes are underlined.

configure ospfv3 area area_identifier add range ipv6netmask [advertise | noadvertise] [inter-prefix | nssa]

configure ospfv3 area area-identifier delete range ipv6Netmask [inter-prefix | nssa]

configure ospfv3 virtual-link {routerid} router-identifier {area} area-identifier restart-helper [none | planned | unplanned | both]

The following show commands now display additional information (shown in bold):

show ospfv3 

OSPFv3              : Enabled            RouterId            : 10.1.1.1 
RouterId Selection  : Configured         ASBR                : No 
ABR                 : No                 ExtLSAs             : 0 
ExtLSAChecksum      : 0x0                OriginateNewLSAs    : 3 
ReceivedNewLSAs     : 0                  SpfHoldTime         : 10s      
Num of Areas        : 1                  10M Cost            : 100          
100M Cost           : 50                                     1000M Cost (1G)     : 40           
10000M Cost (10G)   : 20                 40000M Cost (40G)   : 20           
100000M Cost (100G) : 10 
Num of Areas        : 1                  LSA Batch Interval  : 30s 
10M Cost            : 100                100M Cost           : 50 
1000M Cost (1G)     : 40                 10000M Cost (10G)   : 20 
40000M Cost (40G)   : 20                 100000M Cost (100G) : 10 
Router Alert        : Disabled 
ASExternal LSALimit : Disabled           Timeout (Count)     : Disabled (0) 
Originate Default   : Disabled 
Graceful Restart    : Both               Grace Period        : 120s 
Restart Status      : None 
Last Restart Exit Reason: None 
Import Policy File  : none 
Redistribute: 
  Protocol               Status    Cost      Type  Tag    Policy 
  direct                 Disabled  20        2     ---    none 
  e-bgp                  Disabled  20        2     ---    none 
  i-bgp                  Disabled  20        2     ---    none 
  ripng                  Disabled  20        2     ---    none 
  static                 Disabled  20        2     ---    none 
  isis-level-1           Disabled  20        2     ---    none 
  isis-level-2           Disabled  20        2     ---    none 
  isis-level-1-external  Disabled  20        2     ---    none 
  isis-level-2-external  Disabled  20        2     ---    none

show ospfv3 interfaces detail 

Interface           : v100               Enabled             : ENABLED 
Router              : ENABLED            AreaID              : 0.0.0.0 
RouterID            : 10.1.1.2           Link Type           : point-to-point 
Passive             : No                 Cost                : 40/A 
Priority            : 1                  Transit Delay       : 1s 
Hello Interval      : 10s                Rtr Dead Time       : 40s 
Retransmit Interval : 5s                 Wait Timer          : 40s 
Interface ID        : 19                 Instance ID         : 0 
State               : P2P                Number of state chg : 1 
Hello due in        : 7s                 Number of events    : 2 
Total Num of Nbrs   : 1                  Nbrs in FULL State  : 1 
Hellos Rxed         : 127733             Hellos Txed         : 127739 
DB Description Rxed : 4                  DB Description Txed : 3 
LSA Request Rxed    : 1                  LSA Request Txed    : 1 
LSA Update Rxed     : 2121               LSA Update Txed     : 6156 
LSA Ack Rxed        : 5962               LSA Ack Txed        : 2121 
In Discards         : 0 
DR RtId             : 0.0.0.0            BDR RtId            : 0.0.0.0 
Restart Helper      : Both 
Restart Helper Strict LSA Checking: Enabled      
BFD Protection      : Off

show ospfv3 area detail 

Area Identifier     : 1.0.0.0            Type                : NORM 
Router ID           : 10.1.1.2           Num of Interfaces   : 1 
Spf Runs            : 7                  Num ABRs            : 1 
Num ASBRs           : 0                  Num DC-Bit LSAs     : 0 
Num Indication LSAs : 0                  Num of DoNotAge LSAs: 0 
Num LSAs            : 8                  LSA Chksum          : 0x4d0f7 
Num ASBRs           : 1                  Num LSAs            : 2 
Num Rtr LSAs        : 1                  Num Net LSAs        : 0 
Num Inter-pref LSAs : 0                  Num Inter-rtr LSAs  : 0 
Num Intra-pref LSAs : 1                  Num NSSA LSAs       : 0 
LSA Chksum          : 0xbe09 
Num of Nbrs         : 1                  Num of Virtual Nbrs : 1 
Interfaces: 
Interface Name                  Ospf State    DR ID           BDR ID 
vlan101                         E    BDR      3.0.0.0         2.0.0.0 
Inter-Area route Filter: none 
External route Filter  : none 
Configured Address Ranges: 
Area: 0.0.0.1 Addr: 3100::/64 Type: 3 Advt: Yes 
Addr: 3100::/64 Type: inter-prefix Advt: Yes 
Addr: 3200::/64 Type: nssa         Advt: No

show ospfv3 area detail 

Area Identifier     : 2.0.0.0            Type                : NSSA 
Summary             : Yes                Default Metric      : 10 
Translate           : Candidate (Elected) 
Router ID           : 10.1.4.1           Num of Interfaces   : 1 
Spf Runs            : 14                 Num ABRs            : 1 
Num ASBRs           : 2                  Num LSAs            : 10 
Num Rtr LSAs        : 2                  Num Net LSAs        : 1 
Num Inter-pref LSAs : 4                  Num Inter-rtr LSAs  : 0 
Num Intra-pref LSAs : 1                  Num NSSA LSAs       : 2 
LSA Chksum          : 0x3b142 
Num of Nbrs         : 1                  Num of Virtual Nbrs : 0 
Interfaces: 
Interface Name                  Ospf State    DR ID           BDR ID 
vlan400                         E    BDR      0.0.0.4         0.0.0.3 
Inter-Area route Filter: none 
External route Filter  : none

show ospfv3 lsdb area 0.0.0.2 
                Router LSA for Area 0.0.0.2 
Link State ID    ADV Router       Seq#        Age   Checksum  #Links 
-------------------------------------------------------------------- 
0.0.0.0          0.0.0.3          0x80000004  835   0x9b19    1 
0.0.0.0          0.0.0.4          0x80000004  837   0x8431    1 

                Network LSA for Area 0.0.0.2 

Link State ID    ADV Router       Seq#        Age   Checksum 
------------------------------------------------------------ 
0.15.66.70       0.0.0.4          0x80000003  837   0x423c 

                Inter Area Prefix LSA for Area 0.0.0.2 

Link State ID    ADV Router       Seq#        Age   Checksum 
----------------------------------------------------------- 
0.0.0.2          0.0.0.3          0x80000003  829   0x734d 
0.0.0.3          0.0.0.3          0x80000003  829   0x5521 
0.0.0.4          0.0.0.3          0x80000003  829   0x543 
0.0.0.5          0.0.0.3          0x80000003  808   0x4560 

                NSSA LSA for Area 0.0.0.2 

Link State ID    ADV Router       Seq#        Age   Checksum  MetricType 
------------------------------------------------------------------------ 
0.0.0.2          0.0.0.3          0x80000003  839   0x728f    type-1 
0.0.0.8          0.0.0.4          0x80000003  898   0x5d7f    type-1 

                Intra Area Prefix LSA for Area 0.0.0.2 

Link State ID    ADV Router       Seq#        Age   Checksum  #Prefix  Reference 
---------------------------------------------------------------------------------- 
0.1.0.0          0.0.0.4          0x80000005  838   0x6c9d    1        Network-LSA

show ospfv3 lsdb stats 
Interface vlan100 
------------------------ 
LSA Type           Count 
------------------------ 
Link               2 
Unknown            0 

Interface v1 
------------------------ 
LSA Type           Count 
------------------------ 
Link               0 
Unknown            0 

Area ID 0.0.0.0 
------------------------ 
LSA Type           Count 
------------------------ 
Router             3 
Network            1 
Inter-Area-Prefix  7 
Inter-Area-Router  1 
NSSA               0 
Intra-Area-Prefix  1 
Unknown            0 

Global 
------------------------ 
LSA Type           Count 
------------------------ 
AS External        1 
Unknown            0

show ospfv3 lsdb stats lstype router 

Area ID 0.0.0.0 
------------------------ 
LSA Type           Count 
------------------------ 
Router             3 
Network            0 
Inter-Area-Prefix  0 
Inter-Area-Router  0 
Intra-Area-Prefix  0 
Unknown            0

Deleted CLI Commands

show ospfv3 memory {detail | memoryType}