- Redistribute between RIPv2 and OSPF on R4, it should have 2 summary routes with cost of 50 into OSPF.
- Redistribute between EIGRP and OSPF on R6, it should have 1 summary route and includes the cost needed to reach R6.
Commands:
R4:
router ospf 1
summary-address 30.0.0.0 255.252.0.0
summary-address 31.0.0.0 255.252.0.0
redistribute rip metric 50 subnets
!
router rip
redistribute ospf 1 metric 1
summary-address 30.0.0.0 255.252.0.0
summary-address 31.0.0.0 255.252.0.0
redistribute rip metric 50 subnets
!
router rip
redistribute ospf 1 metric 1
R6:
router eigrp 10
redistribute ospf 1 metric 10000 1000 255 1 1500
!
router ospf 1
summary-address 200.0.0.0 255.255.252.0
redistribute eigrp 10 metric 100 metric-type 1 subnets
verification:
Rack1SW4#show ip route ospf | include E1|E2
O E2 51.51.51.51 [110/20] via 155.1.108.8, 00:01:54, Port-channel1
O E2 204.12.1.0/24 [110/50] via 155.1.108.8, 00:01:54, Port-channel1
O E1 200.0.0.0/24 [110/59173] via 155.1.108.8, 00:01:54, Port-channel1
O E1 54.1.1.0 [110/59173] via 155.1.108.8, 00:01:54, Port-channel1
O E1 200.0.1.0/24 [110/59173] via 155.1.108.8, 00:01:54, Port-channel1
O E1 200.0.2.0/24 [110/59173] via 155.1.108.8, 00:01:54, Port-channel1
O E1 200.0.3.0/24 [110/59173] via 155.1.108.8, 00:01:54, Port-channel1
O E2 31.3.0.0 [110/50] via 155.1.108.8, 00:00:09, Port-channel1
O E2 31.2.0.0 [110/50] via 155.1.108.8, 00:00:10, Port-channel1
O E2 31.1.0.0 [110/50] via 155.1.108.8, 00:00:10, Port-channel1
O E2 31.0.0.0 [110/50] via 155.1.108.8, 00:00:05, Port-channel1
O E2 30.2.0.0 [110/50] via 155.1.108.8, 00:00:20, Port-channel1
O E2 30.3.0.0 [110/50] via 155.1.108.8, 00:00:20, Port-channel1
O E2 30.0.0.0 [110/50] via 155.1.108.8, 00:00:15, Port-channel1
O E2 30.1.0.0 [110/50] via 155.1.108.8, 00:00:20, Port-channel1
OSPF summarization is configured at the ASBR between 2 or more routing domains that does the redistribution by using the summary-address command. These summaries inherit their attributes from the subnets that make them up.
2 types of external routes.
type1 - calculation of external type1 OSPF routes does not distinguish in the routing table between the metric reported by the ASBR, and the metric to the ASBR via the forward metric. Instead Extenal type1 routes represents the metric as cumulative value of the reported metric and the metric to the ASBR.
type 2 - which is the default, do not install the end-to-end metric in the routing table, instead the metric that was reported via the ASBR is installed. The actual routing path is determined by the addition of the reported metric and the metric towards the ASBR, which is called the forward metric.
verification of E2 routes from R4
@ R4 the type2 metric 50 is reflected below.
Rack1SW4#show ip ospf database external 30.0.0.0
OSPF Router with ID (150.1.10.10) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 3 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 30.0.0.0 (External Network Number )
Advertising Router: 150.1.4.4
LS Seq Number: 80000004
Checksum: 0xF3D0
Length: 36
Network Mask: /14
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 50
Forward Address: 0.0.0.0
External Route Tag: 0
OSPF Router with ID (150.1.10.10) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 3 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 30.0.0.0 (External Network Number )
Advertising Router: 150.1.4.4
LS Seq Number: 80000004
Checksum: 0xF3D0
Length: 36
Network Mask: /14
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 50
Forward Address: 0.0.0.0
External Route Tag: 0
we need to verify the metrics from SW4 to SW2, SW2 to R5 and R5 to R4.
for SW4 to SW2 = 150
Rack1SW4#show ip ospf database router 150.1.10.10 self-originate
OSPF Router with ID (150.1.10.10) (Process ID 1)
Router Link States (Area 3)
LS age: 933
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.10.10
Advertising Router: 150.1.10.10
LS Seq Number: 80000001
Checksum: 0x1981
Length: 60
Number of Links: 3
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.108.8
(Link Data) Router Interface address: 155.1.108.10
Number of TOS metrics: 0
TOS 0 Metrics: 150
OSPF Router with ID (150.1.10.10) (Process ID 1)
Router Link States (Area 3)
LS age: 933
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.10.10
Advertising Router: 150.1.10.10
LS Seq Number: 80000001
Checksum: 0x1981
Length: 60
Number of Links: 3
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.108.8
(Link Data) Router Interface address: 155.1.108.10
Number of TOS metrics: 0
TOS 0 Metrics: 150
SW2 to R5 = 30
Rack1SW4#show ip ospf database router 150.1.8.8
OSPF Router with ID (150.1.10.10) (Process ID 1)
Router Link States (Area 3)
LS age: 1 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.8.8
Advertising Router: 150.1.8.8
LS Seq Number: 80000009
Checksum: 0x4078
Length: 72
Number of Links: 4
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.58.5
(Link Data) Router Interface address: 155.1.58.8
Number of TOS metrics: 0
TOS 0 Metrics: 30
R5 to R4 = 10000
Rack1R5#sho ip ospf database router 150.1.5.5 self-originate
OSPF Router with ID (150.1.5.5) (Process ID 1)
Router Link States (Area 0)
LS age: 1004
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.5.5
Advertising Router: 150.1.5.5
LS Seq Number: 8000000C
Checksum: 0x2CC5
Length: 108
Area Border Router
Number of Links: 7
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 150.1.4.4
(Link Data) Router Interface address: 155.1.45.5
Number of TOS metrics: 0
TOS 0 Metrics: 10000
total= 150+30+150 = 10180
Rack1SW4#show ip route 30.0.0.1
Routing entry for 30.0.0.0/14
Known via "ospf 1", distance 110, metric 50, type extern 2, forward metric 10180
Last update from 155.1.108.8 on Port-channel1, 00:16:09 ago
Routing Descriptor Blocks:
* 155.1.108.8, from 150.1.4.4, 00:16:09 ago, via Port-channel1
Route metric is 50, traffic share count is 1
Routing entry for 30.0.0.0/14
Known via "ospf 1", distance 110, metric 50, type extern 2, forward metric 10180
Last update from 155.1.108.8 on Port-channel1, 00:16:09 ago
Routing Descriptor Blocks:
* 155.1.108.8, from 150.1.4.4, 00:16:09 ago, via Port-channel1
Route metric is 50, traffic share count is 1
traceroute:
Rack1SW4#traceroute 30.0.0.1
Type escape sequence to abort.
Tracing the route to 30.0.0.1
1 155.1.108.8 4 msec 4 msec 4 msec
2 155.1.58.5 24 msec 12 msec 16 msec
3 155.1.45.4 20 msec 28 msec 16 msec
4 204.12.1.254 64 msec * 44 msec
Type escape sequence to abort.
Tracing the route to 30.0.0.1
1 155.1.108.8 4 msec 4 msec 4 msec
2 155.1.58.5 24 msec 12 msec 16 msec
3 155.1.45.4 20 msec 28 msec 16 msec
4 204.12.1.254 64 msec * 44 msec
for the calculation of Type1 OSPF External routes. with total metric of 59173
Rack1SW4#show ip route 200.0.0.1
Routing entry for 200.0.0.0/24
Known via "ospf 1", distance 110, metric 59173, type extern 1
Last update from 155.1.108.8 on Port-channel1, 00:26:40 ago
Routing Descriptor Blocks:
* 155.1.108.8, from 150.1.6.6, 00:26:40 ago, via Port-channel1
Route metric is 59173, traffic share count is 1
to verify the total metric composition.
SW4 to SW2, SW2 to R5 and R5 to R6
Rack1SW4#show ip ospf database external 200.0.0.0
OSPF Router with ID (150.1.10.10) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 4 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 200.0.0.0 (External Network Number )
Advertising Router: 150.1.6.6
LS Seq Number: 80000003
Checksum: 0xA0C4
Length: 36
Network Mask: /22
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 100
Forward Address: 0.0.0.0
External Route Tag: 0
OSPF Router with ID (150.1.10.10) (Process ID 1)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 4 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 200.0.0.0 (External Network Number )
Advertising Router: 150.1.6.6
LS Seq Number: 80000003
Checksum: 0xA0C4
Length: 36
Network Mask: /22
Metric Type: 1 (Comparable directly to link state metric)
TOS: 0
Metric: 100
Forward Address: 0.0.0.0
External Route Tag: 0
since ASBR 150.1.6.6 is not in the same area as SW4, we must find the ABR for Area 3 in order to reach R6. in this case it is R5
Rack1SW4#show ip ospf database asbr-summary 150.1.6.6
OSPF Router with ID (150.1.10.10) (Process ID 1)
Summary ASB Link States (Area 3)
Routing Bit Set on this LSA
LS age: 2 (DoNotAge)
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 150.1.6.6 (AS Boundary Router address)
Advertising Router: 150.1.5.5
LS Seq Number: 80000001
Checksum: 0x57AB
Length: 28
Network Mask: /0
TOS: 0 Metric: 58893
OSPF Router with ID (150.1.10.10) (Process ID 1)
Summary ASB Link States (Area 3)
Routing Bit Set on this LSA
LS age: 2 (DoNotAge)
Options: (No TOS-capability, DC, Upward)
LS Type: Summary Links(AS Boundary Router)
Link State ID: 150.1.6.6 (AS Boundary Router address)
Advertising Router: 150.1.5.5
LS Seq Number: 80000001
Checksum: 0x57AB
Length: 28
Network Mask: /0
TOS: 0 Metric: 58893
the above output verifies that R5 is the advertising router-id and is having a metric of 58893 to reach R6. R5 to R6
SW4 to SW2 = 150
Rack1SW4#show ip ospf database external 150.1.10.10 self-originate
OSPF Router with ID (150.1.10.10) (Process ID 1)
Rack1SW4#show ip ospf database router 150.1.10.10 self-originate
OSPF Router with ID (150.1.10.10) (Process ID 1)
Router Link States (Area 3)
LS age: 1817
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.10.10
Advertising Router: 150.1.10.10
LS Seq Number: 80000001
Checksum: 0x1981
Length: 60
Number of Links: 3
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.108.8
(Link Data) Router Interface address: 155.1.108.10
Number of TOS metrics: 0
TOS 0 Metrics: 150
SW2 to R5 = 30
OSPF Router with ID (150.1.10.10) (Process ID 1)
Router Link States (Area 3)
LS age: 1 (DoNotAge)
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 150.1.8.8
Advertising Router: 150.1.8.8
LS Seq Number: 80000009
Checksum: 0x4078
Length: 72
Number of Links: 4
Link connected to: a Stub Network
(Link ID) Network/subnet number: 150.1.8.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.108.8
(Link Data) Router Interface address: 155.1.108.8
Number of TOS metrics: 0
TOS 0 Metrics: 150
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.58.5
(Link Data) Router Interface address: 155.1.58.8
Number of TOS metrics: 0
TOS 0 Metrics: 30
Link connected to: a Stub Network
(Link ID) Network/subnet number: 155.1.8.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 30
total metric is
= SW4 to SW2 + SW2 to R5 + R5 to R6 + R6's metric to external domain
= 150 + 30 + 58893 + 100
= 59173
Rack1SW4#show ip route 200.0.0.1
Routing entry for 200.0.0.0/22, supernet
Known via "ospf 1", distance 110, metric 59173, type extern 1
Last update from 155.1.108.8 on Port-channel1, 00:12:27 ago
Routing Descriptor Blocks:
* 155.1.108.8, from 150.1.6.6, 00:12:27 ago, via Port-channel1
Route metric is 59173, traffic share count is 1
Rack1SW4#traceroute 200.0.0.1
Type escape sequence to abort.
Tracing the route to 200.0.0.1
1 155.1.108.8 0 msec 4 msec 4 msec
2 155.1.58.5 20 msec 16 msec 16 msec
3 155.1.0.1 28 msec 16 msec 16 msec
4 155.1.146.6 48 msec 48 msec 44 msec
5 54.1.1.254 64 msec * 48 msec
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