EIGRP IPv6 - Passive Interface
Passive Interface
EIGRP (Enhanced Interior Gateway Routing Protocol) IPv6 Passive Interface is a configuration feature that allows network administrators to control the participation of a router's interface in EIGRP routing updates for IPv6. When an interface is marked as passive, the router refrains from actively sending EIGRP routing updates out of that specific interface, though it continues to listen for incoming updates. This functionality is particularly useful in scenarios where certain interfaces should not contribute to EIGRP IPv6 routing, such as interfaces connected to non-EIGRP networks or those leading to less critical segments of the network. By configuring IPv6 interfaces as passive, administrators can reduce unnecessary EIGRP traffic on specific links, optimizing network resources and improving overall network efficiency. EIGRP IPv6 Passive Interface provides a means to customize the EIGRP routing behavior based on the specific requirements and topology of an IPv6-enabled network.
Lab:
Disclaimer
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Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.2(4)M1, DEVELOPMENT TEST SOFTWARE
Task 1: Configure IPv6 EIGRP process with Passive interface
Step 1: In the configuration mode of router configure IPv6 EIGRP process on interfaces to send EIGRP updates by following command:
R2:
ipv6 unicast-routing
ipv6 router eigrp 100
interface serial 2/0
ipv6 eigrp 100
exit
interface ethernet 2/0
ipv6 eigrp 100
exit
interface loopback 1
ipv6 eigrp 100
interface loopback 2
ipv6 eigrp 100
interface loopback 3
ipv6 eigrp 100
exit
Step 2: Suppress IPv6 EIGRP updates using “passive-interface” command and “passive-interface default” command
R2:
ipv6 router eigrp 100
passive-interface loopback 3
exit
After suppressing IPv6 EIGRP updates by using passive-interface loopback 3 command, loopback 3 interface is suppressed and not been seen.
R2#show ipv6 eigrp interface
EIGRP-IPv6 Interfaces for AS(100)
Xmit Queue PeerQ Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable Un/Reliable SRTT Un/Reliable Flow Timer Routes
Se2/0 1 0/0 0/0 10 0/16 52 0
Et0/0 1 0/0 0/0 9 0/2 50 0
Lo1 0 0/0 0/0 0 0/0 0 0
Lo2 0 0/0 0/0 0 0/0 0 0
R2:
ipv6 router eigrp 100
passive-interface default
exit
After suppressing IPv6 EIGRP updates by using passive-interface default command, all interface is suppressed and not been seen.
R2#show ipv6 eigrp interfaces
EIGRP-IPv6 Interfaces for AS(100)
Xmit Queue PeerQ Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable Un/Reliable SRTT Un/Reliable Flow Timer Routes
Step 3: Un-suppress IPv6 EIGRP updates using “no passive-interface” command
R2:
ipv6 router eigrp 100
no passive-interface default
exit
After un-suppressing IPv6 EIGRP updates using no passive-interface default command, all interfaces are un-suppress and are seen in IPv6 EIGRP interface table.
R2#show ipv6 eigrp interfaces
EIGRP-IPv6 Interfaces for AS(100)
Xmit Queue PeerQ Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable Un/Reliable SRTT Un/Reliable Flow Timer Routes
Se2/0 1 0/0 0/0 12 0/16 68 0
Et0/0 1 0/0 0/0 5 0/2 50 0
Lo1 0 0/0 0/0 0 0/0 0 0
Lo2 0 0/0 0/0 0 0/0 0 0
Lo3 0 0/0 0/0 0 0/0 0 0
Task 2: Verification:
Step 1: Verify IPv6 EIGRP neighborship by following command:
R2#show ipv6 eigrp neighbors
EIGRP-IPv6 Neighbors for AS(100)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
1 Link-local address: Se2/0 12 00:03:13 16 100 0 9
FE80::A8BB:CCFF:FE00:100
0 Link-local address: Et0/0 13 00:03:13 9 100 0 13
FE80::A8BB:CCFF:FE00:300
Step 2: Verify routing table and IPv6 EIGRP routes by following command:
R2#show ipv6 route
IPv6 Routing Table - default - 21 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, HA - Home Agent, MR - Mobile Router, R - RIP
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, l - LISP
D 11:0:1::/64 [90/2297856]
via FE80::A8BB:CCFF:FE00:100, Serial2/0
D 11:0:2::/64 [90/2297856]
via FE80::A8BB:CCFF:FE00:100, Serial2/0
D 11:0:3::/64 [90/2297856]
via FE80::A8BB:CCFF:FE00:100, Serial2/0
C 12::/64 [0/0]
via Serial2/0, directly connected
L 12::A8BB:CCFF:FE00:200/128 [0/0]
via Serial2/0, receive
C 22:0:1::/64 [0/0]
via Loopback1, directly connected
L 22:0:1::2/128 [0/0]
via Loopback1, receive
C 22:0:2::/64 [0/0]
via Loopback2, directly connected
L 22:0:2::2/128 [0/0]
via Loopback2, receive
C 22:0:3::/64 [0/0]
via Loopback3, directly connected
L 22:0:3::2/128 [0/0]
via Loopback3, receive
C 23::/64 [0/0]
via Ethernet0/0, directly connected
L 23::A8BB:CCFF:FE00:200/128 [0/0]
via Ethernet0/0, receive
D 33:0:1::/64 [90/409600]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 33:0:2::/64 [90/409600]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 33:0:3::/64 [90/409600]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 34::/64 [90/2195456]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 44:0:1::/64 [90/2323456]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 44:0:2::/64 [90/2323456]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
D 44:0:3::/64 [90/2323456]
via FE80::A8BB:CCFF:FE00:300, Ethernet0/0
L FF00::/8 [0/0]
via Null0, receive