Serial Port IP Address

[anand]

My question might be silly, but i need to know, what is the purpose of having IP address on Serial Port, instead we can use the IP address of Ethernet Port by entering "ip unnumbered ethernet 0" on serial port isn't?

[valeriy_k]

Hi

There is at least one significant disadvantage.

When you use routing protocols, such as OSPF/EIGRP/etc,

if you put Ethernet interface in dynamic routing,

serial interface will put automatically,

disallowing to have separate parameters

(such as OSPF area / etc)

Regards

[anand]

i am using EIGRP & the serial port has "ip unnumbered ethernet 0"

router eigrp 4444

network 172.17.0.0

interface ethernet 0

ip address 172.17.21.1 255.255.252.0

but still it workz, but still i am not getting any clearly picture why on a serial port IP address has to me mentioned.can me tell me more clearly? thankz in advance.

[valeriy_k]

Yes, when you building simple network, it's not important.

In case you build medium/large scale network, divided on OSPF area,

you need to assign different interface to different area

on router which is using as ABR (Area Boder Router).

This not possible, if interface has ip unnumbered.