Understanding Administrative Distance
Administrative Distance (AD) is a ranking of believability or trustworthiness of a routing information source. A router uses the routing information base (RIB) also, known as routing table, to determine the path to route traffic to destination networks. Routing information sources inform the router about paths to various networks. These routing information sources include: static routes, connected routes, routing protocols such as RIP, OSPF, BGP, EIGRP. Administrative distance is the first criterion that a router uses when making a path selection decision if two or more routing information sources provide route information for the same destination. It is important to note that before considering the AD in path selection criteria, a router always selects the most specific path to forward traffic regardless of the routing information source.
If a router learns about the path to a prefix from more than one source such as: OSPF, EIGRP, BGP, static routes, routers use AD assigned to each of those sources to to rank the routes and decide which routes should be installed into the routing table and therefore used for routing traffic. The AD is a value that ranges from 0 to 255. The lower the AD of a route source, the more believable its routing information and more likely that its offered routes will be installed into the routing table. Routes with an AD of 255 are not installed in the routing table as they are considered unbelievable. The router will install into the routing table the route from the source with the lowest AD. Each path installed in the routing table has an Administrative Distance. The AD of a route in the RIB indicates that the route was installed from a given source.
In many networks, only one routing protocol is operational. Some scenarios exist where two or more dynamic routing protocols are operational in a network simultaneously such as during a routing protocol migration where one routing protocol is being replaced by another. This results in routing devices in the network receiving routing information from various sources.
AD is a locally significant value. A router does not advertise the AD of its sources to its peers.
Default Administrative Distance
Cisco IOS assigns different ADs to all supported routing information sources. The default AD of the various routing information sources is shown in the following table:
| Route Source | Default Administrative Distance |
| Connected interface | 0 |
| Static route | 1 |
| Enhanced Interior Gateway Routing Protocol (EIGRP) summary route | 5 |
| External Border Gateway Protocol (eBGP) | 20 |
| Internal EIGRP | 90 |
| IGRP | 100 |
| OSPF | 110 |
| Intermediate System-to-Intermediate System (IS-IS) | 115 |
| Routing Information Protocol (RIP) | 120 |
| Exterior Gateway Protocol (EGP) | 140 |
| On Demand Routing (ODR) | 160 |
| External EIGRP | 170 |
| Internal BGP (iBGP) | 200 |
| Unknown* | 255 |
* A route with an administrative distance of 255 will not be installed in the routing table.
The default AD can be modified to implement traffic shaping where traffic follows specific routes according to the design of the network.
Note: AD is used in path selection only if the destination prefix is the same for routes from various routing information sources. In situations where the subnet mask is different, the routing information source with the more specific path will always be used regardless of the AD.
Floating Static Route
A floating static route is a static route whose administrative distance is greater than one (1). Usually, the AD of a floating static is higher than the administrative distance of a similar route that is currently installed in the RIB. The source of the route in the RIB could be a routing protocol such as RIP, EIGRP or another static route. By default, static routes have an administrative distance of 1. In the case of a floating static route, its administrative distance is configured to be higher than the AD of the source of the route to the same destination network in the RIB. This results in the floating static route acting as a backup route to the already existing route in the RIB. The floating static route is not installed in the routing table because its AD is higher than the AD of the current route. It only gets installed in the routing table only when the current route is not present in the routing table.
To configure a floating static route, use the global configuration mode command:
ip route <network-address> <subnet-mask> <next-hop-ip> <1-255>
where <network-address> is the destination network and
<1-255> is the desired AD of the floating
static route.
The following topology is used in the configuration of floating static routes.
Given the following EIGRP sourced route in the routing table with an AD of 90:
R2#show ip route 192.168.118.0
Routing entry for 192.168.118.0/24
Known via "eigrp 1", distance 90, metric 2816, type internal
Redistributing via eigrp 1
Last update from 192.168.12.1 on GigabitEthernet0/0, 01:35:10 ago
Routing Descriptor Blocks:
* 192.168.12.1, from 192.168.12.1, 01:35:10 ago, via GigabitEthernet0/0
Route metric is 2816, traffic share count is 1
Total delay is 12 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1
R2#
To configure a floating static route to the destination network 192.168.118.0/24:
R2(config)#ip route 192.168.118.0 255.255.255.0 192.168.24.2 91
After configuring the following floating static route with an AD of 91,
it will be installed in the routing table only if the EIGRP route fails,
is removed from the routing table and no alternative EIGRP path to the
destination network 192.168.118.0/24 is found with a lower administrative distance.
This can be confirmed by viewing the status of static routes using the command:
show ip static route
R2#show ip static route
Codes: M - Manual static, A - AAA download, N - IP NAT, D - DHCP,
G - GPRS, V - Crypto VPN, C - CASA, P - Channel interface processor,
B - BootP, S - Service selection gateway
DN - Default Network, T - Tracking object
L - TL1, E - OER, I - iEdge
D1 - Dot1x Vlan Network, K - MWAM Route
PP - PPP default route, MR - MRIPv6, SS - SSLVPN
H - IPe Host, ID - IPe Domain Broadcast
U - User GPRS, TE - MPLS Traffic-eng, LI - LIIN
IR - ICMP Redirect
Codes in []: A - active, N - non-active, B - BFD-tracked, D - Not Tracked, P - permanent
Static local RIB for default
M 192.168.118.0/24 [91/0] via 192.168.24.2 [N]
R2#
The floating static route is displayed as being non-active with the code N
If an interface fails, say gigabitherethernet0/0 on device R2, then the floating
static route is added to the routing table. This can be observed from the output
of the debug ip routing
.....
*Feb 20 23:24:57.431: RT: add 192.168.115.0/24 via 192.168.24.2, eigrp metric [170/5376]
*Feb 20 23:24:57.431: RT: delete route to 192.168.118.0 via 192.168.12.1, eigrp metric [90/2816]
*Feb 20 23:24:57.431: RT: no routes to 192.168.118.0, delayed flush
*Feb 20 23:24:57.431: RT: delete network route to 192.168.118.0/24
*Feb 20 23:24:57.431: RT: updating eigrp 192.168.118.0/24 (0x0):
via 192.168.24.2 Gi1/0 1048578
*Feb 20 23:24:57.431: RT: add 192.168.118.0/24 via 192.168.24.2, eigrp metric [170/5376]
R2(config-if)#
*Feb 20 23:24:57.431: RT: delete route to 192.168.112.0 via 192.168.12.1, eigrp metric [90/2816]
*Feb 20 23:24:57.431: RT: no routes to 192.168.112.0, delayed flush
*Feb 20 23:24:57.431: RT: delete network route to 192.168.112.0/24
*Feb 20 23:24:57.431: RT: updating eigrp 192.168.112.0/24 (0x0):
via 192.168.24.2 Gi1/0 1048578
*Feb 20 23:24:57.431: RT: add 192.168.112.0/24 via 192.168.24.2, eigrp metric [170/5376]
*Feb 20 23:24:57.431: RT: delete route to 192.168.111.0 via 192.168.12.1, eigrp metric [90/2816]
*Feb 20 23:24:57.431: RT: no routes to 192.168.111.0, delayed flush
*Feb 20 23:24:57.431: RT: delete network route to 192.168.111.0/24
*Feb 20 23:24:57.431: RT: updating eigrp 192.168.111.0/24 (0x0):
via 192.168.24.2 Gi1/0 1048578
*Feb 20 23:24:57.435: RT: add 192.168.111.0/24 via 192.168.24.2, eigrp metric [170/5376]
*Feb 20 23:24:57.435: RT: updating eigrp 192.168.118.0/24 (0x0):
via 192.168.24.2 Gi1/0 1048578
*Feb 20 23:24:57.443: RT: updating static 192.168.118.0/24 (0x0):
via 192.168.24.2 1048578
*Feb 20 23:24:57.447: RT: closer admin distance for 192.168.118.0, flushing 1 routes
*Feb 20 23:24:57.447: RT: add 192.168.118.0/24 via 192.168.24.2, static metric [91/0]
*Feb 20 23:24:57.519: RT: updating eigrp 192.168.118.0/24 (0x0):
via 192.168.24.2 Gi1/0 1048578
*Feb 20 23:24:57.523: RT: rib update return code: 17
*Feb 20 23:24:59.115: %LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to administratively down
*Feb 20 23:24:59.119: is-up: GigabitEthernet0/0 0 state: 6 sub state: 1 line: 1
*Feb 20 23:25:00.115: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to down
*Feb 20 23:25:00.123: is-up: GigabitEthernet0/0 0 state: 6 sub state: 1 line: 1
R2(config-if)#
.....
From the output of the command debug ip route, initially, the
alternate external EIGRP route with an administrative distance of
170 is installed for the lost path to the destination network 192.168.118.0/24.
However, this path is deleted and replaced with the path from the floating
static route because of its lower administrative distance of 91.
The floating static route can be confirmed to have been installed in the routing
table using the commands: show ip static route and
show ip route 192.168.118.0 as shown below:
R2#show ip static route
Codes: M - Manual static, A - AAA download, N - IP NAT, D - DHCP,
G - GPRS, V - Crypto VPN, C - CASA, P - Channel interface processor,
B - BootP, S - Service selection gateway
DN - Default Network, T - Tracking object
L - TL1, E - OER, I - iEdge
D1 - Dot1x Vlan Network, K - MWAM Route
PP - PPP default route, MR - MRIPv6, SS - SSLVPN
H - IPe Host, ID - IPe Domain Broadcast
U - User GPRS, TE - MPLS Traffic-eng, LI - LIIN
IR - ICMP Redirect
Codes in []: A - active, N - non-active, B - BFD-tracked, D - Not Tracked, P - permanent
Static local RIB for default
M 192.168.118.0/24 [91/0] via 192.168.24.2 [A]
R2#show ip route 192.168.118.0
Routing entry for 192.168.118.0/24
Known via "static", distance 91, metric 0
Routing Descriptor Blocks:
* 192.168.24.2
Route metric is 0, traffic share count is 1
Modification of Administrative Distance
Modification of the administrative distance of a routing protocol is usually not recommended when optimizing network traffic flows. Scenarios, however, exist that require the modification of the default AD of one routing source resulting in the paths advertised by that routing source being installed in the routing table such as complex redistribution particularly in large networks.
Usually modification of the AD of a routing information source results in the instantaneous ranking of the paths from the different sources. However, this depends of the speed of convergence of the routing information sources. With IGPs this takes place almost instantly. However, BGP is slow to converge and therefore if the AD of BGP is the lowest, the BGP learned route will take a while before it is installed into the RIB.
BGP
By default, iBGP has an AD of 200 and eBGP has an AD of 20.
In many networks running BGP, an IGP is usually configured to support routing in the internal network. BGP is usually used to share prefixes between external networks. The low AD of eBGP reflects this preference for eBGP routes to be preferred to IGP routes for external prefixes and IGP paths to be preferred for internal prefixes.
AD of eBGP and iBGP Routes
The AD of iBGP routes can be modified using the BGP address-family command:
distance <ebgp-distance> <ibgp-distance>. In the
following configuration, the eBGP AD is set to 15 and iBGP AD is set to 121.
R1(config)#router bgp 65000
R1(config-router)#address-family ipv4 unicast
R1(config-router-af)#distance ?
<1-255> Administrative distance
bgp BGP distance
mbgp MBGP distance
R1(config-router-af)#distance bgp 15 121
AD of Specific BGP Routes
The AD of specific BGP routes can be modified using the command:
distance <1-255> <network-address> <wildcard-mask>. In the
following configuration, the AD for the route 192.168.1.0 with a subnet mask of
255.255.255.0 is set to 89.
R1(config)#router bgp 65000
R1(config-router)#address-family ipv4 unicast
R1(config-router-af)#distance 89 192.168.1.0 0.0.0.255
NOTE: After modifying the AD of BGP, take note that BGP is a little slow to converge so the configurations will take a while to take effect.
EIGRP
By default, the Administrative Distance for EIGRP internal routes is 90, external routes (routes redistributed into EIGRP) is 170 and EIGRP summary routes is 5. The default administrative distance in EIGRP can be modified for routes that are internal, external or per route. If the AD of a route is modified, EIGRP's Diffusing Update ALgorith (DUAL) is run due to the route configuration.
Modifying the AD of Internal and External Routes
The EIGRP default administrative distance for internal and external routes
can be modified using the distance <internal> <external> command:
For EIGRP classic mode, the AD for internal routes is modified to 70 and external routes to 105.
R4(config)#router eigrp 1
R4(config-router)#distance eigrp 70 105
For EIGRP named mode, the AD modifications are implemented under address-family topology configuration mode:
R1(config)#router eigrp EIGRP-NAMED
R1(config-router)#address-family ipv4 unicast autonomous-system 1
R1(config-router-af)#topology base
R1(config-router-af-topology)#distance eigrp 70 105
Modifying AD for Individual Routes
The AD for individual routes can be modified using the command:
distance <1-255> <network-address> <wildcard-mask>
R1(config)#router eigrp EIGRP-NAMED
R1(config-router)#address-family ipv4 unicast autonomous-system 1
R1(config-router-af)#topology base
R1(config-router-af-topology)#distance 60 192.168.12.0 0.0.0.3
Floating Summary Route
A floating summary route is created by configuring a default route and an administrative
distance at the interface level or address family interface level. It is configured using the
classical EIGRP interface command ip summary-address eigrp or
EIGRP named mode af-interface command summary-address.
The configuration of a default summary route on an upstream router blocks the advertisement of more specific routes to downstream routers by intermediate routers. This problem can be resolved by configration of a floating summary route. On the upstream router that advertised the default summary route, an AD greater than the default EIGRP AD is added to the floating summary route.
R4(config)#interface g1/0
R4(config-if)#ip summary-address eigrp 1 0.0.0.0 0.0.0.0 252
On some IOS versions, adding the AD to a ip summary-address eigrp
command is deprecated. The EIGRP router-mode command
summary-metric is instead used:
R4(config)#interface g1/0
R4(config-if)#ip summary-address eigrp 1 0.0.0.0 0.0.0.0 252
%EIGRP: summary-address accepted but distance option deprecated; use summary-metric command for distance.
R4(config-if)#router eigrp 1
R4(config-router)#summary-metric 0.0.0.0 0.0.0.0 distance 252
OSPF
Given a routing table, EIGRP topology table and OSPF database table below, the modification of the OSPF AD affects what routes get populated in the RIB.
R1#show ip route | ex Connected
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
+ - replicated route, % - next hop override
Gateway of last resort is not set
192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.12.0/30 is directly connected, GigabitEthernet0/0
L 192.168.12.1/32 is directly connected, GigabitEthernet0/0
192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.13.0/30 is directly connected, GigabitEthernet1/0
L 192.168.13.1/32 is directly connected, GigabitEthernet1/0
192.168.24.0/30 is subnetted, 1 subnets
D 192.168.24.0
[90/15360] via 192.168.12.2, 01:09:44, GigabitEthernet0/0
192.168.34.0/30 is subnetted, 1 subnets
D 192.168.34.0
[90/20480] via 192.168.12.2, 01:09:44, GigabitEthernet0/0
D 192.168.41.0/24
[90/2575360] via 192.168.12.2, 00:14:37, GigabitEthernet0/0
D 192.168.42.0/24
[90/2575360] via 192.168.12.2, 00:14:23, GigabitEthernet0/0
D 192.168.43.0/24
[90/2575360] via 192.168.12.2, 00:14:08, GigabitEthernet0/0
D 192.168.44.0/24
[90/2575360] via 192.168.12.2, 00:13:58, GigabitEthernet0/0
192.168.45.0/30 is subnetted, 1 subnets
D 192.168.45.0
[90/20480] via 192.168.12.2, 01:09:44, GigabitEthernet0/0
O IA 192.168.46.0/24 [110/3] via 192.168.13.2, 00:00:46, GigabitEthernet1/0
O IA 192.168.47.0/24 [110/3] via 192.168.13.2, 00:00:56, GigabitEthernet1/0
O IA 192.168.48.0/24 [110/3] via 192.168.13.2, 00:00:56, GigabitEthernet1/0
O IA 192.168.49.0/24 [110/3] via 192.168.13.2, 00:01:35, GigabitEthernet1/0
R1#show ip eigrp topology
EIGRP-IPv4 VR(EIGRP-NAMED) Topology Table for AS(1)/ID(192.168.13.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 192.168.24.0/30, 1 successors, FD is 1966080
via 192.168.12.2 (1966080/1310720), GigabitEthernet0/0
P 192.168.34.0/30, 1 successors, FD is 2621440
via 192.168.12.2 (2621440/1966080), GigabitEthernet0/0
P 192.168.12.0/30, 1 successors, FD is 1310720
via Connected, GigabitEthernet0/0
P 192.168.45.0/30, 1 successors, FD is 2621440
via 192.168.12.2 (2621440/1966080), GigabitEthernet0/0
P 192.168.13.0/30, 1 successors, FD is 1310720
via Connected, GigabitEthernet1/0
P 192.168.41.0/24, 1 successors, FD is 329646080
via 192.168.12.2 (329646080/328990720), GigabitEthernet0/0
P 192.168.42.0/24, 1 successors, FD is 329646080
via 192.168.12.2 (329646080/328990720), GigabitEthernet0/0
P 192.168.44.0/24, 1 successors, FD is 329646080
via 192.168.12.2 (329646080/328990720), GigabitEthernet0/0
P 192.168.43.0/24, 1 successors, FD is 329646080
via 192.168.12.2 (329646080/328990720), GigabitEthernet0/0
R1#show ip ospf database
OSPF Router with ID (192.168.13.1) (Process ID 1)
Router Link States (Area 0)
Link ID ADV Router Age Seq# Checksum Link count
192.168.13.1 192.168.13.1 313 0x80000004 0x00E0EC 2
192.168.34.1 192.168.34.1 2347 0x80000004 0x0045B6 2
192.168.45.1 192.168.45.1 194 0x8000000B 0x002C78 6
Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.13.2 192.168.34.1 2347 0x80000002 0x00E44E
192.168.34.2 192.168.45.1 314 0x80000003 0x0023CE
Summary Net Link States (Area 0)
Link ID ADV Router Age Seq# Checksum
192.168.46.0 192.168.45.1 230 0x80000001 0x009775
192.168.47.0 192.168.45.1 240 0x80000001 0x008C7F
192.168.48.0 192.168.45.1 240 0x80000001 0x008189
192.168.49.0 192.168.45.1 278 0x80000001 0x007693
R1#
R1#show ip ospf database router 192.168.45.1
OSPF Router with ID (192.168.13.1) (Process ID 1)
Router Link States (Area 0)
Routing Bit Set on this LSA in topology Base with MTID 0
LS age: 231
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 192.168.45.1
Advertising Router: 192.168.45.1
LS Seq Number: 8000000B
Checksum: 0x2C78
Length: 96
Area Border Router
Number of Links: 6
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.41.0
(Link Data) Network Mask: 255.255.255.0
Number of MTID metrics: 0
TOS 0 Metrics: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.42.0
(Link Data) Network Mask: 255.255.255.0
Number of MTID metrics: 0
TOS 0 Metrics: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.43.0
(Link Data) Network Mask: 255.255.255.0
Number of MTID metrics: 0
TOS 0 Metrics: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.44.0
(Link Data) Network Mask: 255.255.255.0
Number of MTID metrics: 0
TOS 0 Metrics: 1
Link connected to: a Stub Network
(Link ID) Network/subnet number: 192.168.45.0
(Link Data) Network Mask: 255.255.255.252
Number of MTID metrics: 0
TOS 0 Metrics: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 192.168.34.2
(Link Data) Router Interface address: 192.168.34.2
Number of MTID metrics: 0
TOS 0 Metrics: 1
OSPF has a default AD of 110 for all OSPF routes: intra-area, inter-area and external (routes redistributed into OSPF). OSPF offers a variety of options for modifying the default administrative distance. The AD of OSPF can be modified for intra-area, inter-area and external routes. Additionally, the AD can be modified for a single route, group of routes, or all routes.
Intra-Area Routes
The OSPF AD of only intra-area routes can be modified using the OSPF router mode command
distance ospf intra-area <1-255>:
R1(config)#router ospf 1
R1(config-router)#distance ospf intra-area 89
The routing table installs the OSPF intra-area routes instead of the EIGRP sourced routes because OSPF intra-area routes have an AD of 89 which is lower than the EIGRP AD of 90. Notice that the inter-area routes still have their AD at the default of 110.
Inter-area Routes
The AD of only OSPF inter-area routes can be modified using the OSPF router mode command:
distance ospf inter-area <1-255> where distance is the desired AD.
R1(config)#router ospf 1
R1(config-router)#distance ospf inter-area 50
External Routes
The AD of routes redistributed into OSPF (external) can be modified using the
router OSPF mode command distance ospf external 150.
R1(config)#router ospf 1
R1(config-router)#distance ospf external 150
The following output shows the effect of the previous modifications of the OSPF AD for intra-area, inter-area and external routes:
R1(config-router)#do show 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
+ - replicated route, % - next hop override
Gateway of last resort is not set
192.168.5.0/29 is subnetted, 1 subnets
O E2 192.168.5.8 [150/20] via 192.168.13.2, 00:00:10, GigabitEthernet1/0
192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.12.0/30 is directly connected, GigabitEthernet0/0
L 192.168.12.1/32 is directly connected, GigabitEthernet0/0
192.168.13.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.13.0/30 is directly connected, GigabitEthernet1/0
L 192.168.13.1/32 is directly connected, GigabitEthernet1/0
192.168.24.0/30 is subnetted, 1 subnets
D 192.168.24.0
[90/15360] via 192.168.12.2, 02:13:45, GigabitEthernet0/0
192.168.34.0/30 is subnetted, 1 subnets
O 192.168.34.0 [89/2] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O 192.168.41.0/24 [89/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O 192.168.42.0/24 [89/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O 192.168.43.0/24 [89/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O 192.168.44.0/24 [89/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
192.168.45.0/30 is subnetted, 1 subnets
O 192.168.45.0 [89/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O IA 192.168.46.0/24 [50/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O IA 192.168.47.0/24 [50/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O IA 192.168.48.0/24 [50/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
O IA 192.168.49.0/24 [50/3] via 192.168.13.2, 00:06:05, GigabitEthernet1/0
R1(config-router)#
OSPF Changing AD of Specific Route
OSPF provides the capability for the AD of a specific route to be modified using the
OSPF router mode command: distance <1-255> <network-adress> <wildcard>
R1(config)#router ospf 1
R1(config-router)#distance 21 192.168.44.0 0.0.0.255
OSPF AD for All Routes
To modify the AD for all OSPF routes, use the OSPF route mode command:
distance <1-255>
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