Craig A. Huegen c-huegen at
Fri Aug 2 18:57:07 UTC 1996

On Fri, 2 Aug 1996, Avi Freedman wrote:

==>We usually use unnumbered interfaces, though, for singly-connected customers
==>(unless their routers can't support unnumbered interfaces).  The only
==>major gotcha with that is that if they're using a Real Router (that deleted
==>routes associated with interfaces that aren't available), you can't
==>get to their router if their ethernet is down...

Actually, with release 11.0(x) on 1000-series (can't confirm on other
routers), unnumbered will still work with downed ethernet.

We use ip unnumbered on all remote ISDN and frame routers for cisco's
employees.  Even if the remote Ethernet interface is up/down or
admin-down/down, we can still reach the router over the BRI interface or
serial interface.

I know that older IOS releases wouldn't let you, though.

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