[dhcwg] Question re. interpretation of option 33 destination addr

Richard Johnson <raj@cisco.com> Sat, 10 July 2004 03:53 UTC

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To: dhcwg@ietf.org
From: Richard Johnson <raj@cisco.com>
Date: Fri, 9 Jul 2004 18:24:46 -0700
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Subject: [dhcwg] Question re. interpretation of option 33 destination addr
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I have a question about the interpretation of the destination address 
in option 33.  Looking at RFC2132, it's not really clear how this 
address should be interpreted.

Since we now have a "classless static route" option, it seems clear 
that option 33 was a "classfull static route" option.  That being the 
case, it seems clear that given a destination address of "10.1.1.0", 
the subnet mask which should go along with this would be the classfull 
mask of 255.0.0.0.  Fine.  But given a destination address of 
"10.1.1.0" (and an assumed mask of 255.0.0.0), is this a host route?  
It would seem so.  But is that what was intended?  Or, instead, should 
the client system AND the destination address with the classfull mask 
in order to produce a subnet route (in this case "10.0.0.0/8")?

My first thoughts would be that in order to keep as much flexibility as 
possible, the destination address should NOT be AND'ed with the 
classfull mask and if the destination address happens to have bits set 
in the "host" portion of the address, then it should assumed that this 
is a "host route".  If a "subnet route" were intended, then bits would 
not have been set in the "host" portion of the address.

The real question, however, is how is this currently handled and what 
is the expectation?

/raj


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