The use of RIPng

Jeff McAdams jeffm at
Tue Jun 1 21:58:03 CEST 2010

On 6/1/10 2:42 PM, bmanning at wrote:
> 	here we must part ways... sort of by definition, if there is
> 	a routing protocol running, its a router - granted (as you
> 	point out below) it may not forward packets (dependent on
> 	configuration options) but -understanding- the network topology
> 	past next-hop is a key attribute of routing.

> 	so other than defintional terms, i'm almost with you. :)

Huh, I tend to think of a router as a system that, you know, routes. 
Call me crazy.  That may, or may not, involve a routing protocol.  And a 
routing protocol, which is used to share topology and routing 
information, need not be used by a system to make decisions about 
routing.  Sure, that's by far and away the most common use of routing 
protocol information, but I think going from the premise of a system 
running a routing protocol software to that system necessarily being a 
router is fraught with semantic peril.

There are any of a number of reasons that a system could run routing 
protocol software and never forward a single packet, nor even have the 
capability of forwarding a packet.  I think calling those systems 
routers will lead to no end of confusion and you'll please pardon me if 
I think your definition of "router" leaves more than a little bit to be 

> --bill
>> If you run a routing protocol on an end-station - you've given that
>> end-station a mechanism that it might learn what the network topology is
>> in the overall network, beyond just its default next-hop.  You *might*
>> let it be a router, depending on how that routing protocol is set up and
>> other configuration issues within the OS.  ( echo 0>
>> /proc/sys/net/ipv4/ip_forward    pretty much makes a Linux box *not* be
>> an IPv4 router, regardless of what software is running on it (yeah,
>> yeah, unless you start getting into user-space routing and such))  You
>> might also give that end-station the ability to inject routes into that
>> network topology, which could, indeed, cause problems.
>> So, there are use cases where it could be beneficial for end-stations to
>> have knowledge of the overall network topology by running a routing
>> protocol.  There are also, almost certainly drawbacks.  I think it is
>> possible for reasonable people to disagree (including based on their
>> individual scenarios for use-case) on which is bigger, the benefits or
>> the drawbacks.
>> --
>> Jeff McAdams
>> jeffm at

Jeff McAdams
jeffm at

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