this thread is cracking me up! but you're tossing up some good questions, and
hopefully, you're learning how the OSPF router ID is assigned.
The statement from p.1 is multiple *loopback* interfaces, not multiple
*addresses* on a loopback interface; using the following scenario as an
example
interface loopback 0
ip address 172.16.1.1 255.255.248.0
interface loopback 1
ip address 172.16.200.1 255.255.248.0
interface ethernet 0
ip address 192.168.5.1 255.255.255.0
interface serial 0
ip address 192.168.10.1 255.255.255.252
(No mention of secondaries, although your point is likely correct and well
taken)
thus in this scenario, the loopback 1 address would become the OSPF router ID
because its IP address is higher than loopback 0, even though the physical
interfaces have higher IP addresses, because OSPF prefers the *highest
numbered loopback address*
if loopback 1 did not exist, loopback 0 address would become the OSPF router
ID because OSPF prefers *loopback over physical* interfaces for router ID,
even though the physical interfaces have higher addresses
if neither loopback existed, serial 0 address would become the OSPF router ID
because it has the highest IP address
capiche?
LOL... dazed, amazed and amused on a Friday vacation-day
-e-
----- Original Message -----
From: "Oleg Mazurov" <[EMAIL PROTECTED]>
Newsgroups: groupstudy.cisco
To: <[EMAIL PROTECTED]>
Sent: Friday, April 06, 2001 9:20 AM
Subject: Re: OSPF Router ID
> "Howard C. Berkowitz" wrote:
> >
> > > > The latter is wrong. The order of selection is:
> > >>
> > >> 1. Numerically highest IP addresss on a loopback interface, when
> > >> there are multiple loopback addresses.
> > >>
> > >> 2. IP address on the loopback address when only a single loopback
> > >>is defined.
> > >>
> > >> 3. Numerically highest IP address on an active physical (or
> > >>logical other than
> > >> loopback address)--active as in no shutdown
> > >
> > >I have a strong feeling that p.2 doesn't make any sense.
> >
> > Point 2 should read "on the loopback interface" Is that your concern?
> >
>
> When only a single loopback interface is defined, it's address is the
> highest of available loopback addresses, right?
>
> BTW, p.1 is wrong for ciscos. When multiple IP addresses are defined on
> a loopback interface, OSPF takes only primary address of it and ignores
> the secondaries.
>
> /felis
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