Voice gateway have same IP address to 2 GigabitEthernet port

[nagaraj789]

Guys,

I came across strange issue wherein one of voice gateway was having same IP addresss assigned to 2 GigabitEthernet ports, One showing up while other is standby mode. But don't see any resilience configuration on both ports. Now questions are: 

1. Is it possible to have same ip address on 2  GigabitEthernet ports in same router.

2. Whats meant standby mode here?

+++++++++++++++++++++++++++++++++++++

VG#sh ip int bri
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 10.10.10.11 YES NVRAM up up
GigabitEthernet0/0/1 10.10.10.11 YES NVRAM standby mode down

[Vaijanath Sonvane]

Yes, you can configure two interfaces with same IP address with backup interface command. In your case, GigabitEthernet0/0/1 interface must be defined as backup interface. When the router receives an indication that the primary interface is down, the backup interface is enabled. After the primary connection is restored for a specified period, the backup interface is disabled

Check below post for more details:

https://community.cisco.com/t5/other-network-architecture/router-backup-interface/td-p/200000 

[nagaraj789]

Thanks Vijnath for quick response! Much Appreciated.

Indeed,GigabitEthernet0/0/0 interface has been configured as backup interface but i don't see other resilience related configuration.

Is it enough to have resilience by configuring GigabitEthernet0/0/0 interface as backup interface?

Will GigabitEthernet0/0/1 be up & active when GigabitEthernet0/0/0 port goes down?

VG#sh ip int bri
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 10.10.10.11 YES NVRAM up up
GigabitEthernet0/0/1 10.10.10.11 YES NVRAM standby mode down

interface GigabitEthernet0/0/0
backup interface GigabitEthernet0/0/1
ip address 10.10.10.11 255.255.255.0
media-type rj45
speed 100
no negotiation auto
!
interface GigabitEthernet0/0/1
ip address 10.10.10.11 255.255.255.0
media-type rj45
speed 100
no negotiation auto

[Nithin Eluvathingal]

Your configuration is correct. Go through the below guide if you need to learn more about "Configuring Backup Interfaces"

https://www.cisco.com/c/en/us/td/docs/routers/access/1900/software/configuration/guide/Software_Configuration/backup.html

[Vaijanath Sonvane]

Only backup interface GigabitEthernet0/0/1 command is required for interface resiliency.

Yes, GigabitEthernet0/0/1 be up & active when GigabitEthernet0/0/0 port goes down.

The posted configuration is correct.