Subinterface with PPP

Unanswered Question
Jun 9th, 2009
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I having two routers connectin HO & Branch office. encapsulation configured in PPP. For some routing decision, I tried to configure subinterface like ser 0/0.1 & ser 0/0.2

interface serial 0/0

no ip address


interface serial 0/0.1

ip address

no shutdown

interface serial 0/0.2

ip address

no shutdown

After doing this I am not able to ping the serial interface IP address from each other routers.

Is this the practise. Whether it will workout? I am aware that in Frame-relay encapsulation is will work. How about PPP/HDLC

with thanks


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Overall Rating: 5 (1 ratings)
Giuseppe Larosa Tue, 06/09/2009 - 09:15
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Hello R.B. Kumar,

HDLC doesn't support subinterfaces and this explains what you have seen (it is the default encapsulation)

PPP might support subinterfaces with different addressing this means two different IPCP sessions running on the link.

But the support is not complete at least it wasn't when I tested it some years ago.

I would go with FR to be sure of subinterfaces support.

Hope to help



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