& Switching v5 Workbook -
Advanced Technology Labs - IP
CCIE Routing
CCIE R&S v5
Routing
Floating Static Routes
You must load the initial configuration files for the section, Basic IP
Addressing, which can be found in
. Reference the Advanced Technology Labs
With Addressing Diagram to complete this task.
Task
Configure R4 and R5 with identical IPv4 static routes for each other’s Loopback0
prefixes through both the directly connected Ethernet segment and the DMVPN
cloud.
Use administrative distance to ensure that traffic is primarily routed over the Ethernet
segment, but is rerouted through the DMVPN cloud if the Ethernet link is down.
Configuration
R4:
ip route 150.1.5.5 255.255.255.255 GigabitEthernet1.45 10
ip route 150.1.5.5 255.255.255.255 155.1.0.5 20
R5:
ip route 150.1.4.4 255.255.255.255 GigabitEthernet1.45 10
ip route 150.1.4.4 255.255.255.255 155.1.0.4 20
Verification
When a router receives identical routes (prefix and prefix-length) through multiple
routing protocols (static or dynamic), the decision regarding which one gets installed
in the routing table is based on the lowest administrative distance; lower AD values
have higher preference. With static routing, this principle can be used for simple
redundancy by configuring a backup route with a higher administrative distance than
the primary route. In this example, R5 installs the route to 150.1.4.4/32 via
GigabitEthernet1.45 with an administrative distance of 10. When the link
GigabitEthernet1.45 is down, the route with the next-lowest administrative distance,
150.1.4.4/32 via 155.1.0.4 with a distance of 20, is installed. The result is that traffic
is routed out Ethernet link unless it is down, in which case traffic is rerouted out the
DMVPN cloud.
Verify the active route in the routing table, as well as the RIB entries.
R5#show ip route 150.1.4.4
Routing entry for150.1.4.4/32
Known via "static",distance 10
, metric 0 (connected)
Routing Descriptor Blocks: * directly connected,via GigabitEthernet1.45
Route metric is 0, traffic share count is 1
!R5#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 150.1.4.4/32 [10/0] via GigabitEthernet1.45 [A]
M[20/0] via 155.1.0.4 [N]
Use traceroute to verify the active path of the traffic, before and after disabling the
Ethernet link.
R5#traceroute 150.1.4.4
Type escape sequence to abort.
Tracing the route to 150.1.4.4
VRF info: (vrf in name/id, vrf out name/id)1 155.1.45.4 3 msec * 3 msec
!R5#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.R5(config)#interface GigabitEthernet1.45
R5(config-if)#shutdown
!R5#show ip route 150.1.4.4
Routing entry for150.1.4.4/24
Known via "static",distance 20
, metric 0
Routing Descriptor Blocks: *155.1.0.4
Route metric is 0, traffic share count is 1
!R5#traceroute 150.1.4.4
Type escape sequence to abort.
Tracing the route to 150.1.4.4
VRF info: (vrf in name/id, vrf out name/id)1 155.1.0.4 4 msec * 3 msec