Hi CSC,
I was running a debug on my DR during some OSPF labs.
The setup was very basic, all area 0, LSA1 and 2 only. No redistribution or multiple areas.
I added a loopback on one of the routers and advertised it in Area 0 directly under the interface. I noticed the following from the debugs on my DR and was wondering why there was mention of Type 7 external routes and what the "sync for area dummy" was? Is this just part of the SPF calculations that will try and happen regardless of whether there is actually anything to calculate?
Oct 15 14:43:15.395: OSPF-1 INTER: Entered inter-area route sync for area 0
*Oct 15 14:43:15.395: OSPF-1 EXTER: Started Building Type 7 External Routes
*Oct 15 14:43:15.395: OSPF-1 EXTER: Entered External route sync for area dummy a
*Oct 15 14:43:15.395: OSPF-1 EXTER: Entered External route sync for area dummy a
rea
*Oct 15 14:43:15.395: OSPF-1 EXTER: Entered NSSA route sync for area 0
*Oct 15 14:43:15.395: OSPF-1 EXTER: Entered NSSA route sync for area 0
Some other output showing nothing but LSA1/2.
Router_5#sh ip ospf data
OSPF Router with ID (10.0.0.5) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 2014 0x80000003 0x007C74 2
2.2.2.2 2.2.2.2 1483 0x80000004 0x00E098 3
3.3.3.3 3.3.3.3 1190 0x80000004 0x0066D9 3
4.4.4.4 4.4.4.4 1926 0x80000003 0x004C7D 2
10.0.0.5 10.0.0.5 1929 0x80000003 0x008A61 1
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
10.0.0.5 10.0.0.5 1929 0x80000003 0x0036A0
Router_5#
Router_5#
Router_5#sh ip route
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override
Gateway of last resort is not set
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/11] via 10.0.0.1, 01:05:18, Ethernet0/0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/11] via 10.0.0.2, 01:05:18, Ethernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/11] via 10.0.0.3, 01:05:18, Ethernet0/0
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/11] via 10.0.0.4, 01:04:47, Ethernet0/0
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.0.0.0/24 is directly connected, Ethernet0/0
L 10.0.0.5/32 is directly connected, Ethernet0/0
22.0.0.0/32 is subnetted, 1 subnets
O 22.22.22.22 [110/11] via 10.0.0.2, 00:58:23, Ethernet0/0
33.0.0.0/32 is subnetted, 1 subnets
O 33.33.33.33 [110/11] via 10.0.0.3, 00:53:34, Ethernet0/0
Router_5#
