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New Member

Cisco Router 1941 Interface IP Change

Hi Cisco Family,


I have a question about Cisco Router/Switch Interface IP changes. This router is used exclusivly for our VoIP network only. Keep in mind i tried to find specific documentation on the results/effects of this action but couldnt find nothing in particular. I have a Cisco router 1941 (as you can tell), more like 3 of them but this one in particular I'm going to be changing an Interfaces ip address. The root question is what exactly happens or defaults once and IP address is changes on an interface? I know it depend on wether the interface is used for LAN or WAN purposes but ill get more specific and post a screenshot. I'm working with 3 interfaces. Serial 0/0/0, GE 0/0 and GE 0/1. Serial 0/0/0 is used for our primary PTP connection with our phone server at our Colo datacenter where it resides. GE 0/0 is the LAN ofcourse where the IP Phones reside. GE 0/1 is used solely as a fail over / backup connection in the event the PTP fails. The serial 0/0/0 uses a T1 DSU/CSU HWIC card while the others are integrated. GE 0/1 uses from my knowledge a VPN connection if Serial 0/0/0 fails. The device this Cisco 1941 router connects too is a another 1941 at our datacenter. So i believe reconfiguring the VPN settings might have to be done as well as applying the access-list back to the new ip address on the same interface. I apologize for the lengthly discussion. The screenshot of each interface is attached in order Serial 0/0/0, GE 0/1, GE 0/0. Thank you for your highly valued time guys and ladies.


Hello.Not clear what IP


Not clear what IP-address (interface) you are going to change.

The best practice regarding IP-address change is:

  1. establish management session over backup interface (path);
  2. make manual switchover (traffic to secondary);
  3. reconfigure interface;
  4. make manual swithover back to primary;
  5. compare routing with baseline.
New Member

Thank you Vasilii, i was

Thank you Vasilii, i was swept up in the details so sorry for leaving that out. Im changing interface ge 0/1. Since its the backup interface which always stays active i was wondering if you'd recommended turning the interfaqce off before programming. Also i was thinking exactly what you mentioned about comparing the changes that occur after chaing the ip with a show ip interface and going step by step through the screen print out.

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