[Bulk] [Xorp-users] Question about ospf protocol implementation on XORP

Mike Horn caddisconsulting@yahoo.com
Sat, 12 Nov 2005 17:44:16 -0700


Hi Riccardo,

Very good questions, I think you are mixing a few terms.  The fact that OSPF
uses the hello process to discover neighbors does not make it a link-state
routing protocol (RIP also uses hellos for neighbor discovery, but it is a
distance vector routing protocol).  In OSPF once a neighbor is discovered
there is a database exchange, this is how information about the network
topology is initially propogated, not by the hello messages themselves.
What makes OSPF a link-state routing protocol is that each router
contributes to the link-state database and routing updates are event driven
(change in link state) rather than being announce at a fixed interval like
RIP.

You are correct that you should be able to configure 2 XORP routers on a
broadcast network, like Ethernet, and have them automatically discover each
other.  Right now the OSPF code is pretty new, so it's not too surprising if
you are experiencing some issues.  I'll send you some working lab configs
next week.

-mike

-----Original Message-----
From: xorp-users-admin@xorp.org [mailto:xorp-users-admin@xorp.org] On Behalf
Of riccardo.sciaccaluga@tin.it
Sent: Saturday, November 12, 2005 8:39 AM
To: xorp-users@xorp.org
Subject: [Bulk] [Xorp-users] Question about ospf protocol implementation on
XORP

Hi
I have been reading all the exchanged mail about establishing ospf
adiacences but i have a question.
Ospf is supposed to be a link state
packet routing protocol; this means the protocol is able to build up its
knowledge about the network topology by itself with hello packets exchange
so the questiopn is:
Why in the config file sample exchanged inside the mail i have been looking
at, there is the declaration of the neighbours id(adress) for each interface
of the router?
Moreover how
could it be a simple config file just to run ospf protocol on routers placed
in a simple network topology A<-->B<-->C....i mean how could it be a simple
config file that let the router exchanging hello packets and building up the
network topology by themselves?
Thank in advance

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